parallel

#!/usr/bin/env perl

# Copyright (C) 2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017
# Ole Tange and Free Software Foundation, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>
# or write to the Free Software Foundation, Inc., 51 Franklin St,
# Fifth Floor, Boston, MA 02110-1301 USA

# open3 used in Job::start
use IPC::Open3;
# &WNOHANG used in reaper
use POSIX qw(:sys_wait_h setsid ceil :errno_h);
# gensym used in Job::start
use Symbol qw(gensym);
# tempfile used in Job::start
use File::Temp qw(tempfile tempdir);
# mkpath used in openresultsfile
use File::Path;
# GetOptions used in get_options_from_array
use Getopt::Long;
# Used to ensure code quality
use strict;
use File::Basename;

save_stdin_stdout_stderr();
save_original_signal_handler();
parse_options();
::debug("init", "Open file descriptors: ", join(" ",keys %Global::fd), "\n");
my $number_of_args;
if($Global::max_number_of_args) {
    $number_of_args = $Global::max_number_of_args;
} elsif ($opt::X or $opt::m or $opt::xargs) {
    $number_of_args = undef;
} else {
    $number_of_args = 1;
}

my @command = @ARGV;

my @input_source_fh;
if($opt::pipepart) {
    if($opt::tee) {
	@input_source_fh = map { open_or_exit($_) } @opt::a;
	# Remove the first: It will be the file piped.
	shift @input_source_fh;
	if(not @input_source_fh and not $opt::pipe) {
	    @input_source_fh = (*STDIN);
	}
    } else {
	# -a is used for data - not for command line args
	@input_source_fh = map { open_or_exit($_) } "/dev/null";
    }
} else {
    @input_source_fh = map { open_or_exit($_) } @opt::a;
    if(not @input_source_fh and not $opt::pipe) {
	@input_source_fh = (*STDIN);
    }
}
if($opt::sqlmaster) {
    # Create SQL table to hold joblog + output
    $Global::sql->create_table($#input_source_fh+1);
    if($opt::sqlworker) {
	# Start a real --sqlworker in the background later
	$Global::start_sqlworker = 1;
	$opt::sqlworker = undef;
    }
}

if($opt::skip_first_line) {
    # Skip the first line for the first file handle
    my $fh = $input_source_fh[0];
    <$fh>;
}

set_input_source_header();

if($opt::filter_hosts and (@opt::sshlogin or @opt::sshloginfile)) {
    # Parallel check all hosts are up. Remove hosts that are down
    filter_hosts();
}

if($opt::nonall or $opt::onall) {
    onall(\@input_source_fh,@command);
    wait_and_exit(min(undef_as_zero($Global::exitstatus),254));
}

# TODO --transfer foo/./bar --cleanup
# multiple --transfer and --basefile with different /./

$Global::JobQueue = JobQueue->new(
    \@command,\@input_source_fh,$Global::ContextReplace,
    $number_of_args,\@Global::transfer_files,\@Global::ret_files);

if($opt::pipepart) {
    pipepart_setup();
} elsif($opt::pipe and $opt::tee) {
    pipe_tee_setup();
}

if($opt::eta or $opt::bar or $opt::shuf or $Global::halt_pct) {
    # Count the number of jobs or shuffle all jobs
    # before starting any.
    # Must be done after ungetting any --pipepart jobs.
    $Global::JobQueue->total_jobs();
}
# Compute $Global::max_jobs_running
# Must be done after ungetting any --pipepart jobs.
max_jobs_running();

init_run_jobs();
my $sem;
if($Global::semaphore) {
    $sem = acquire_semaphore();
}
$SIG{TERM} = \&start_no_new_jobs;
start_more_jobs();
if($opt::tee) {
    # All jobs must be running in parallel for --tee
    $Global::start_no_new_jobs = 1;
} elsif($opt::pipe and not $opt::pipepart) {
    spreadstdin();
}
::debug("init", "Start draining\n");
drain_job_queue();
::debug("init", "Done draining\n");
reaper();
::debug("init", "Done reaping\n");
::debug("init", "Cleaning\n");
if($Global::semaphore) {
    $sem->release();
}
cleanup();
::debug("init", "Halt\n");
halt();

sub set_input_source_header {
    if($opt::header and not $opt::pipe) {
	# split with colsep or \t
	# $header force $colsep = \t if undef?
	my $delimiter = defined $opt::colsep ? $opt::colsep : "\t";
	# regexp for {=
	my $left = "\Q$Global::parensleft\E";
	my $l = $Global::parensleft;
	# regexp for =}
	my $right = "\Q$Global::parensright\E";
	my $r = $Global::parensright;
	my $id = 1;
	for my $fh (@input_source_fh) {
	    my $line = <$fh>;
	    chomp($line);
	    ::debug("init", "Delimiter: '$delimiter'");
	    for my $s (split /$delimiter/o, $line) {
		::debug("init", "Colname: '$s'");
		# Replace {colname} with {2}
		for(@command,@Global::ret_files,@Global::transfer_files,
		    $opt::tagstring, $opt::workdir, $opt::results, $opt::retries) {
		    # Skip if undefined
		    $_ or next;
		  s:\{$s(|/|//|\.|/\.)\}:\{$id$1\}:g;
		    # {=header1 ... =}  =>  {=1 ... =}
		  s:$left $s (.*?) $right:$l$id$1$r:gx;
		}
		$Global::input_source_header{$id} = $s;
		$id++;
	    }
	}
    } else {
	my $id = 1;
	for my $fh (@input_source_fh) {
	    $Global::input_source_header{$id} = $id;
	    $id++;
	}
    }
}

sub max_jobs_running {
    if(not $Global::max_jobs_running) {
	# Compute $Global::max_jobs_running
	for my $sshlogin (values %Global::host) {
	    $sshlogin->max_jobs_running();
	}
    }
    return $Global::max_jobs_running;
}

sub halt {
    if($opt::halt and $Global::halt_when ne "never") {
	if(not defined $Global::halt_exitstatus) {
	    if($Global::halt_pct) {
		$Global::halt_exitstatus =
		    ::ceil($Global::total_failed / $Global::total_started * 100);
	    } elsif($Global::halt_count) {
		$Global::halt_exitstatus =
		    ::min(undef_as_zero($Global::total_failed),101);
	    }
	}
	wait_and_exit($Global::halt_exitstatus);
    } else {
	wait_and_exit(min(undef_as_zero($Global::exitstatus),101));
    }
}

sub __PIPE_MODE__ {}

sub pipepart_setup {
    if($opt::tee) {
	# Prepend each command with
	#   cat file
	my $cat_string = "cat ".::shell_quote_scalar($opt::a[0]);
	for(1..$Global::JobQueue->total_jobs()) {
	    push @Global::cat_prepends, $cat_string;
	}
    } else {
	if(not $opt::blocksize) {
	    # --blocksize with 10 jobs per jobslot
	    $opt::blocksize = -10;
	}
	if($opt::roundrobin) {
	    # --blocksize with 1 job per jobslot
	    $opt::blocksize = -1;
	}
	if($opt::blocksize < 0) {
	    my $size = 0;
	    # Compute size of -a
	    for(@opt::a) {
		if(-f $_) {
		    $size += -s $_;
		} elsif(-b $_) {
		    $size += size_of_block_dev($_);
		} else {
		    ::error("$_ is neither a file nor a block device");
		    wait_and_exit(255);
		}
	    }
	    # Run in total $job_slots*(- $blocksize) jobs
	    # Set --blocksize = size / no of proc / (- $blocksize)
	    $Global::dummy_jobs = 1;
	    $Global::blocksize = 1 +
		int($size / max_jobs_running() / -$opt::blocksize);
	}
	@Global::cat_prepends = map { pipe_part_files($_) } @opt::a;
	# Unget the empty arg as many times as there are parts
	$Global::JobQueue->{'commandlinequeue'}{'arg_queue'}->unget(
	    map { [Arg->new("\0")] } @Global::cat_prepends
	    );
    }
}

sub pipe_tee_setup {
    # mkfifo t1..5
    my @fifos;
    for(1..$Global::JobQueue->total_jobs()) {
	push @fifos, tmpfifo();
    }
    # cat foo | tee t1 t2 t3 t4 t5 > /dev/null
    if(not fork()){
	# Let tee inherit our stdin
	# and redirect stdout to null
	open STDOUT, ">","/dev/null";
	exec "tee",@fifos;
    }

    # Make cats for each fifo
    #   cat t1 | grep 1
    #   cat t2 | grep 2
    #   cat t3 | grep 3
    #   cat t4 | grep 4
    #   cat t5 | grep 5
    # Remove the tmpfifo as soon as it is open
    # 'exec' saves a process
    @Global::cat_prepends = map { "(rm $_; exec cat) < $_" } @fifos;
}

sub pipe_part_files {
    # Input:
    #   $file = the file to read
    # Returns:
    #   @commands that will cat_partial each part
    my ($file) = @_;
    my $buf = "";
    if(not -f $file and not -b $file) {
	::error("$file is not a seekable file.");
	::wait_and_exit(255);
    }
    my $header = find_header(\$buf,open_or_exit($file));
    # find positions
    my @pos = find_split_positions($file,$Global::blocksize,length $header);
    # Make @cat_prepends
    my @cat_prepends = ();
    for(my $i=0; $i<$#pos; $i++) {
	push(@cat_prepends,
	     cat_partial($file, 0, length($header), $pos[$i], $pos[$i+1]));
    }
    return @cat_prepends;
}

sub find_header {
    # Input:
    #   $buf_ref = reference to read-in buffer
    #   $fh = filehandle to read from
    # Uses:
    #   $opt::header
    #   $Global::blocksize
    # Returns:
    #   $header string
    my ($buf_ref, $fh) = @_;
    my $header = "";
    if($opt::header) {
	if($opt::header eq ":") { $opt::header = "(.*\n)"; }
	# Number = number of lines
	$opt::header =~ s/^(\d+)$/"(.*\n)"x$1/e;
	while(read($fh,substr($$buf_ref,length $$buf_ref,0),$Global::blocksize)) {
	    if($$buf_ref=~s/^($opt::header)//) {
		$header = $1;
		last;
	    }
	}
    }
    return $header;
}

sub find_split_positions {
    # Input:
    #   $file = the file to read
    #   $block = (minimal) --block-size of each chunk
    #   $headerlen = length of header to be skipped
    # Uses:
    #   $opt::recstart
    #   $opt::recend
    # Returns:
    #   @positions of block start/end
    my($file, $block, $headerlen) = @_;
    my $size = -s $file;
    if(-b $file) {
	# $file is a blockdevice
	$size = size_of_block_dev($file);
    }
    $block = int $block;
    # The optimal dd blocksize for mint, redhat, solaris, openbsd = 2^17..2^20
    # The optimal dd blocksize for freebsd = 2^15..2^17
    my $dd_block_size = 131072; # 2^17
    my @pos;
    my ($recstart,$recend) = recstartrecend();
    my $recendrecstart = $recend.$recstart;
    my $fh = ::open_or_exit($file);
    push(@pos,$headerlen);
    for(my $pos = $block+$headerlen; $pos < $size; $pos += $block) {
	my $buf;
	if($recendrecstart eq "") {
	    push(@pos,$pos);
	} else {
	    seek($fh, $pos, 0) || die;
	    while(read($fh,substr($buf,length $buf,0),$dd_block_size)) {
		if($opt::regexp) {
		    # If match /$recend$recstart/ => Record position
		    if($buf =~ /^(.*$recend)$recstart/os) {
			# Start looking for next record _after_ this match
			$pos += length($1);
			push(@pos,$pos);
			last;
		    }
		} else {
		    # If match $recend$recstart => Record position
		    # TODO optimize to only look at the appended $dd_block_size + len $recendrecstart
		    # TODO increase $dd_block_size to optimize for longer records
		    my $i = index64(\$buf,$recendrecstart);
		    if($i != -1) {
			# Start looking for next record _after_ this match
			$pos += $i + length($recend);
			push(@pos,$pos);
			last;
		    }
		}
	    }
	}
    }
    push(@pos,$size);
    close $fh;
    return @pos;
}

sub cat_partial {
    # Input:
    #   $file = the file to read
    #   ($start, $end, [$start2, $end2, ...]) = start byte, end byte
    # Returns:
    #   Efficient command to copy $start..$end, $start2..$end2, ... to stdout
    my($file, @start_end) = @_;
    my($start, $i);
    # Convert start_end to start_len
    my @start_len = map {
	if(++$i % 2) { $start = $_; } else { $_-$start }
    } @start_end;
    # This can read 7 GB/s using a single core
    my $script = spacefree
	(0,
	 q{
	     while(@ARGV) {
		 sysseek(STDIN,shift,0) || die;
		 $left = shift;
		 while($read =
		       sysread(STDIN,$buf, $left > 131072 ? 131072 : $left)){
		     $left -= $read;
		     syswrite(STDOUT,$buf);
		 }
	     }
	 });
    return "<". shell_quote_scalar($file) .
	" perl -e '$script' @start_len";
}

sub spreadstdin {
    # read a record
    # Spawn a job and print the record to it.
    # Uses:
    #   $Global::blocksize
    #   STDIN
    #   $opt::r
    #   $Global::max_lines
    #   $Global::max_number_of_args
    #   $opt::regexp
    #   $Global::start_no_new_jobs
    #   $opt::roundrobin
    #   %Global::running
    # Returns: N/A

    if($opt::tee) {
	# Spawn all jobs
	# read a record
	# Write record to all jobs
	if(not $Global::JobQueue->empty()) {
	    ::error("--tee requres --jobs to be higher. Try --jobs 0.");
	}
    }

    my $buf = "";
    my ($recstart,$recend) = recstartrecend();
    my $recendrecstart = $recend.$recstart;
    my $chunk_number = 1;
    my $one_time_through;
    my $two_gb = 2**31-1;
    my $blocksize = $Global::blocksize;
    my $in = *STDIN;
    my $header = find_header(\$buf,$in);
    while(1) {
      my $anything_written = 0;
      my $buflen = length $buf;
      my $readsize = ($buflen < $blocksize) ? $blocksize-$buflen : $blocksize;
      # If $buf < $blocksize, append so it is $blocksize long after reading.
      # Otherwise append a full $blocksize
      if(not read($in,substr($buf,$buflen,0),$readsize)) {
	  # End-of-file
	  $chunk_number != 1 and last;
	  # Force the while-loop once if everything was read by header reading
	  $one_time_through++ and last;
      }
      if($opt::r) {
	  # Remove empty lines
	  $buf =~ s/^\s*\n//gm;
	  if(length $buf == 0) {
	      next;
	  }
      }
      if($Global::max_lines and not $Global::max_number_of_args) {
	  # Read n-line records
	  my $n_lines = $buf =~ tr/\n/\n/;
	  my $last_newline_pos = rindex64(\$buf,"\n");
	  while($n_lines % $Global::max_lines) {
	      $n_lines--;
	      $last_newline_pos = rindex64(\$buf,"\n",$last_newline_pos-1);
	  }
	  # Chop at $last_newline_pos as that is where n-line record ends
	  $anything_written +=
	      write_record_to_pipe($chunk_number++,\$header,\$buf,
				   $recstart,$recend,$last_newline_pos+1);
	  shorten(\$buf,$last_newline_pos+1);
      } elsif($opt::regexp) {
	  if($Global::max_number_of_args) {
	      # -N => (start..*?end){n}
	      # -L -N => (start..*?end){n*l}
	      my $read_n_lines =
		  $Global::max_number_of_args * ($Global::max_lines || 1);
	      while($buf =~ s/((?:$recstart.*?$recend){$read_n_lines})($recstart.*)$/$2/os) {
		  # Copy to modifiable variable
		  my $b = $1;
		  $anything_written +=
		      write_record_to_pipe($chunk_number++,\$header,\$b,
					   $recstart,$recend,length $1);
	      }
	  } else {
	      eof($in) and last;
	      # Find the last recend-recstart in $buf
	      if($buf =~ s/(.*$recend)($recstart.*?)$/$2/os) {
		  # Copy to modifiable variable
		  my $b = $1;
		  $anything_written +=
		      write_record_to_pipe($chunk_number++,\$header,\$b,
					   $recstart,$recend,length $1);
	      }
	  }
      } else {
	  if($Global::max_number_of_args) {
	      # -N => (start..*?end){n}
	      my $i = 0;
	      my $read_n_lines =
		  $Global::max_number_of_args * ($Global::max_lines || 1);
	      while(($i = nindex(\$buf,$recendrecstart,$read_n_lines)) != -1) {
		  $i += length $recend; # find the actual splitting location
		  $anything_written +=
		      write_record_to_pipe($chunk_number++,\$header,\$buf,
					   $recstart,$recend,$i);
		  shorten(\$buf,$i);
	      }
	  } else {
	      eof($in) and last;
	      # Find the last recend+recstart in $buf
	      my $i = rindex64(\$buf,$recendrecstart);
	      if($i != -1) {
		  $i += length $recend; # find the actual splitting location
		  $anything_written +=
		      write_record_to_pipe($chunk_number++,\$header,\$buf,
					   $recstart,$recend,$i);
		  shorten(\$buf,$i);
	      }
	  }
      }
      if(not $anything_written
	 and not eof($in)
	 and not $Global::no_autoexpand_block) {
	  # Nothing was written - maybe the block size < record size?
	  # Increase blocksize exponentially up to 2GB-1 (2GB causes problems)
	  if($blocksize < $two_gb) {
	      my $old_blocksize = $blocksize;
	      $blocksize = ::min(ceil($blocksize * 1.3 + 1), $two_gb);
	      ::warning("A record was longer than $old_blocksize. " .
			"Increasing to --blocksize $blocksize.");
	  }
      }
    }
    ::debug("init", "Done reading input\n");

    # If there is anything left in the buffer write it
    write_record_to_pipe($chunk_number++, \$header, \$buf, $recstart,
			 $recend, length $buf);

    if($opt::retries) {
	$Global::no_more_input = 1;
	# We need to start no more jobs: At most we need to retry some
	# of the already running.
	my @running = values %Global::running;
	# Stop any virgins.
	for my $job (@running) {
	    if(defined $job and $job->virgin()) {
		close $job->fh(0,"w");
	    }
	}
	# Wait for running jobs to be done
	my $sleep =1;
	while($Global::total_running > 0) {
	    $sleep = ::reap_usleep($sleep);
	}
    }
    $Global::start_no_new_jobs ||= 1;
    if($opt::roundrobin) {
	# Flush blocks to roundrobin procs
	my $sleep = 1;
	while(%Global::running) {
	    my $something_written = 0;
	    for my $job (values %Global::running) {
		if($job->block_length()) {
		    $something_written += $job->non_blocking_write();
		} else {
		    close $job->fh(0,"w");
		}
	    }
	    if($something_written) {
		$sleep = $sleep/2+0.001;
	    }
	    $sleep = ::reap_usleep($sleep);
	}
    }
}

sub recstartrecend {
    # Uses:
    #   $opt::recstart
    #   $opt::recend
    # Returns:
    #   $recstart,$recend with default values and regexp conversion
    my($recstart,$recend);
    if(defined($opt::recstart) and defined($opt::recend)) {
	# If both --recstart and --recend is given then both must match
	$recstart = $opt::recstart;
	$recend = $opt::recend;
    } elsif(defined($opt::recstart)) {
	# If --recstart is given it must match start of record
	$recstart = $opt::recstart;
	$recend = "";
    } elsif(defined($opt::recend)) {
	# If --recend is given then it must match end of record
	$recstart = "";
	$recend = $opt::recend;
    }

    if($opt::regexp) {
	# If $recstart/$recend contains '|' this should only apply to the regexp
	$recstart = "(?:".$recstart.")";
	$recend = "(?:".$recend.")";
    } else {
	# $recstart/$recend = printf strings (\n)
	$recstart =~ s/\\([0rnt\'\"\\])/"qq|\\$1|"/gee;
	$recend =~ s/\\([0rnt\'\"\\])/"qq|\\$1|"/gee;
    }
    return ($recstart,$recend);
}

sub nindex {
    # See if string is in buffer N times
    # Returns:
    #   the position where the Nth copy is found
    my ($buf_ref, $str, $n) = @_;
    my $i = 0;
    for(1..$n) {
	$i = index64($buf_ref,$str,$i+1);
	if($i == -1) { last }
    }
    return $i;
}

{
    my @robin_queue;
    my $sleep = 1;

    sub round_robin_write {
	# Input:
	#   $header_ref = ref to $header string
	#   $block_ref = ref to $block to be written
	#   $recstart = record start string
	#   $recend = record end string
	#   $endpos = end position of $block
	# Uses:
	#   %Global::running
	# Returns:
	#   $something_written = amount of bytes written
	my ($header_ref,$buffer_ref,$recstart,$recend,$endpos) = @_;
	my $written = 0;
	my $block_passed = 0;
	while(not $block_passed) {
	    # Continue flushing existing buffers
	    # until one is empty and a new block is passed
	    if(@robin_queue) {
		# Rotate queue once so new blocks get a fair chance
		# to be given to another block
		push @robin_queue, shift @robin_queue;
	    } else {
		# Make a queue to spread the blocks evenly
		push @robin_queue, (sort { $a->seq() <=> $b->seq() }
				    values %Global::running);
	    }
	    if($opt::keeporder) {
		for my $job (@robin_queue) {
		    if($job->block_length() > 0) {
			$written += $job->non_blocking_write();
		    } else {
			$job->set_block($header_ref,$buffer_ref,$endpos,$recstart,$recend);
			$block_passed = 1;
			$job->set_virgin(0);
			$written += $job->non_blocking_write();
			last;
		    }
		}
	    } else {
		do {
		    $written = 0;
		    for my $job (@robin_queue) {
			if($job->block_length() > 0) {
			    $written += $job->non_blocking_write();
			} else {
			    $job->set_block($header_ref,$buffer_ref,
					    $endpos,$recstart,$recend);
			    $block_passed = 1;
			    $job->set_virgin(0);
			    $written += $job->non_blocking_write();
			    last;
			}
		    }
		    if($written) {
			$sleep = $sleep/1.5+0.001;
		    }
		} while($written and not $block_passed);
	    }
	    $sleep = ::reap_usleep($sleep);
	}
	return $written;
    }
}

sub index64 {
    # Do index on strings > 2GB.
    # index in Perl < v5.22 does not work for > 2GB
    # Input:
    #   as index except STR which must be passed as a reference
    # Output:
    #   as index
    my $ref = shift;
    my $match = shift;
    my $pos = shift || 0;
    my $block_size = 2**31-1;
    my $strlen   = length($$ref);
    # No point in doing extra work if we don't need to.
    if($strlen < $block_size or $] > 5.022) {
	return index($$ref, $match, $pos);
    }

    my $matchlen = length($match);
    my $ret;
    my $offset = $pos;
    while($offset < $strlen) {
	$ret = index(
	    substr($$ref, $offset, $block_size),
	    $match, $pos-$offset);
	if($ret != -1) {
	    return $ret + $offset;
	}
	$offset += ($block_size - $matchlen - 1);
    }
    return -1;
}

sub rindex64 {
    # Do rindex on strings > 2GB.
    # rindex in Perl < v5.22 does not work for > 2GB
    # Input:
    #   as rindex except STR which must be passed as a reference
    # Output:
    #   as rindex
    my $ref = shift;
    my $match = shift;
    my $pos = shift;
    my $block_size = 2**31-1;
    my $strlen = length($$ref);
    # Default: search from end
    $pos = defined $pos ? $pos : $strlen;
    # No point in doing extra work if we don't need to.
    if($strlen < $block_size) {
	return rindex($$ref, $match, $pos);
    }

    my $matchlen = length($match);
    my $ret;
    my $offset = $pos - $block_size + $matchlen;
    if($offset < 0) {
	# The offset is less than a $block_size
	# Set the $offset to 0 and
	# Adjust block_size accordingly
	$block_size = $block_size + $offset;
	$offset = 0;
    }
    while($offset >= 0) {
	$ret = rindex(
	    substr($$ref, $offset, $block_size),
	    $match);
	if($ret != -1) {
	    return $ret + $offset;
	}
	$offset -= ($block_size - $matchlen - 1);
    }
    return -1;
}

sub shorten {
    # Do: substr($buf,0,$i) = "";
    # Some Perl versions do not support $i > 2GB, so do this in 2GB chunks
    # Input:
    #   $buf_ref = \$buf
    #   $i = position to shorten to
    # Returns: N/A
    my ($buf_ref, $i) = @_;
    my $two_gb = 2**31-1;
    while($i > $two_gb) {
        substr($$buf_ref,0,$two_gb) = "";
        $i -= $two_gb;
    }
    substr($$buf_ref,0,$i) = "";
}

sub write_record_to_pipe {
    # Fork then
    # Write record from pos 0 .. $endpos to pipe
    # Input:
    #   $chunk_number = sequence number - to see if already run
    #   $header_ref = reference to header string to prepend
    #   $buffer_ref = reference to record to write
    #   $recstart = start string of record
    #   $recend = end string of record
    #   $endpos = position in $buffer_ref where record ends
    # Uses:
    #   $Global::job_already_run
    #   $opt::roundrobin
    #   @Global::virgin_jobs
    # Returns:
    #   Number of chunks written (0 or 1)
    my ($chunk_number,$header_ref,$buffer_ref,$recstart,$recend,$endpos) = @_;
    if($endpos == 0) { return 0; }
    if(vec($Global::job_already_run,$chunk_number,1)) { return 1; }
    if($opt::roundrobin) {
	# Write the block to one of the already running jobs
	return round_robin_write($header_ref,$buffer_ref,$recstart,$recend,$endpos);
    }
    # If no virgin found, backoff
    my $sleep = 0.0001; # 0.01 ms - better performance on highend
    while(not @Global::virgin_jobs) {
	::debug("pipe", "No virgin jobs");
	$sleep = ::reap_usleep($sleep);
	# Jobs may not be started because of loadavg
	# or too little time between each ssh login
	# or retrying failed jobs.
	start_more_jobs();
    }
    my $job = shift @Global::virgin_jobs;
    # Job is no longer virgin
    $job->set_virgin(0);

    if($opt::retries) {
	# Copy $buffer[0..$endpos] to $job->{'block'}
	# Remove rec_sep
	# Run $job->add_transfersize
	$job->set_block($header_ref,$buffer_ref,$endpos,$recstart,$recend);
	if(fork()) {
	    # Skip
	} else {
	    $job->write($job->block_ref());
	    close $job->fh(0,"w");
	    exit(0);
	}
    } else {
	# We ignore the removed rec_sep which is technically wrong.
	$job->add_transfersize($endpos + length $$header_ref);
	if(fork()) {
	    # Skip
	} else {
	    # Chop of at $endpos as we do not know how many rec_sep will
	    # be removed.
	    substr($$buffer_ref,$endpos,length $$buffer_ref) = "";
	    # Remove rec_sep
	    if($opt::remove_rec_sep) {
		Job::remove_rec_sep($buffer_ref,$recstart,$recend);
	    }
	    $job->write($header_ref);
	    $job->write($buffer_ref);
	    close $job->fh(0,"w");
	    exit(0);
	}
    }
    close $job->fh(0,"w");
    return 1;
}


sub __SEM_MODE__ {}


sub acquire_semaphore {
    # Acquires semaphore. If needed: spawns to the background
    # Uses:
    #   @Global::host
    # Returns:
    #   The semaphore to be released when jobs is complete
    $Global::host{':'} = SSHLogin->new(":");
    my $sem = Semaphore->new($Semaphore::name,$Global::host{':'}->max_jobs_running());
    $sem->acquire();
    if($Semaphore::fg) {
	# skip
    } else {
	if(fork()) {
	    exit(0);
	} else {
	    # If run in the background, the PID will change
	    $sem->pid_change();
	}
    }
    return $sem;
}


sub __PARSE_OPTIONS__ {}


sub options_hash {
    # Returns:
    #   %hash = the GetOptions config
    return
	("debug|D=s" => \$opt::D,
	 "xargs" => \$opt::xargs,
	 "m" => \$opt::m,
	 "X" => \$opt::X,
	 "v" => \@opt::v,
	 "sql=s" => \$opt::retired,
	 "sqlmaster=s" => \$opt::sqlmaster,
	 "sqlworker=s" => \$opt::sqlworker,
	 "sqlandworker=s" => \$opt::sqlandworker,
	 "joblog|jl=s" => \$opt::joblog,
	 "results|result|res=s" => \$opt::results,
	 "resume" => \$opt::resume,
	 "resume-failed|resumefailed" => \$opt::resume_failed,
	 "retry-failed|retryfailed" => \$opt::retry_failed,
	 "silent" => \$opt::silent,
	 "keep-order|keeporder|k" => \$opt::keeporder,
	 "no-keep-order|nokeeporder|nok|no-k" => \$opt::nokeeporder,
	 "group" => \$opt::group,
	 "g" => \$opt::retired,
	 "ungroup|u" => \$opt::ungroup,
	 "linebuffer|linebuffered|line-buffer|line-buffered|lb" => \$opt::linebuffer,
	 "tmux" => \$opt::tmux,
	 "tmuxpane" => \$opt::tmuxpane,
	 "null|0" => \$opt::null,
	 "quote|q" => \$opt::q,
	 # Replacement strings
	 "parens=s" => \$opt::parens,
	 "rpl=s" => \@opt::rpl,
	 "plus" => \$opt::plus,
	 "I=s" => \$opt::I,
	 "extensionreplace|er=s" => \$opt::U,
	 "U=s" => \$opt::retired,
	 "basenamereplace|bnr=s" => \$opt::basenamereplace,
	 "dirnamereplace|dnr=s" => \$opt::dirnamereplace,
	 "basenameextensionreplace|bner=s" => \$opt::basenameextensionreplace,
	 "seqreplace=s" => \$opt::seqreplace,
	 "slotreplace=s" => \$opt::slotreplace,
	 "jobs|j=s" => \$opt::jobs,
	 "delay=f" => \$opt::delay,
	 "sshdelay=f" => \$opt::sshdelay,
	 "load=s" => \$opt::load,
	 "noswap" => \$opt::noswap,
	 "max-line-length-allowed" => \$opt::max_line_length_allowed,
	 "number-of-cpus" => \$opt::number_of_cpus,
	 "number-of-cores" => \$opt::number_of_cores,
	 "use-cpus-instead-of-cores" => \$opt::use_cpus_instead_of_cores,
	 "shellquote|shell_quote|shell-quote" => \$opt::shellquote,
	 "nice=i" => \$opt::nice,
	 "tag" => \$opt::tag,
	 "tagstring|tag-string=s" => \$opt::tagstring,
	 "onall" => \$opt::onall,
	 "nonall" => \$opt::nonall,
	 "filter-hosts|filterhosts|filter-host" => \$opt::filter_hosts,
	 "sshlogin|S=s" => \@opt::sshlogin,
	 "sshloginfile|slf=s" => \@opt::sshloginfile,
	 "controlmaster|M" => \$opt::controlmaster,
	 "ssh=s" => \$opt::ssh,
	 "transfer-file|transferfile|transfer-files|transferfiles|tf=s"
	 => \@opt::transfer_files,
	 "return=s" => \@opt::return,
	 "trc=s" => \@opt::trc,
	 "transfer" => \$opt::transfer,
	 "cleanup" => \$opt::cleanup,
	 "basefile|bf=s" => \@opt::basefile,
	 "B=s" => \$opt::retired,
	 "ctrlc|ctrl-c" => \$opt::retired,
	 "noctrlc|no-ctrlc|no-ctrl-c" => \$opt::retired,
	 "workdir|work-dir|wd=s" => \$opt::workdir,
	 "W=s" => \$opt::retired,
	 "rsync-opts|rsyncopts=s" => \$opt::rsync_opts,
	 "tmpdir|tempdir=s" => \$opt::tmpdir,
	 "use-compress-program|compress-program=s" => \$opt::compress_program,
	 "use-decompress-program|decompress-program=s" => \$opt::decompress_program,
	 "compress" => \$opt::compress,
	 "tty" => \$opt::tty,
	 "T" => \$opt::retired,
	 "H=i" => \$opt::retired,
	 "dry-run|dryrun|dr" => \$opt::dryrun,
	 "progress" => \$opt::progress,
	 "eta" => \$opt::eta,
	 "bar" => \$opt::bar,
	 "shuf" => \$opt::shuf,
	 "arg-sep|argsep=s" => \$opt::arg_sep,
	 "arg-file-sep|argfilesep=s" => \$opt::arg_file_sep,
	 "trim=s" => \$opt::trim,
	 "env=s" => \@opt::env,
	 "recordenv|record-env" => \$opt::record_env,
	 "plain" => \$opt::plain,
	 "profile|J=s" => \@opt::profile,
	 "pipe|spreadstdin" => \$opt::pipe,
	 "robin|round-robin|roundrobin" => \$opt::roundrobin,
	 "recstart=s" => \$opt::recstart,
	 "recend=s" => \$opt::recend,
	 "regexp|regex" => \$opt::regexp,
	 "remove-rec-sep|removerecsep|rrs" => \$opt::remove_rec_sep,
	 "files|output-as-files|outputasfiles" => \$opt::files,
	 "block|block-size|blocksize=s" => \$opt::blocksize,
	 "tollef" => \$opt::tollef,
	 "gnu" => \$opt::gnu,
	 "link|xapply" => \$opt::link,
	 "linkinputsource|xapplyinputsource=i" => \@opt::linkinputsource,
	 "bibtex|citation" => \$opt::citation,
	 "wc|willcite|will-cite|nn|nonotice|no-notice" => \$opt::willcite,
	 # Termination and retries
	 "halt-on-error|halt=s" => \$opt::halt,
	 "limit=s" => \$opt::limit,
	 "memfree=s" => \$opt::memfree,
	 "retries=s" => \$opt::retries,
	 "timeout=s" => \$opt::timeout,
	 "termseq|term-seq=s" => \$opt::termseq,
	 # xargs-compatibility - implemented, man, testsuite
	 "max-procs|P=s" => \$opt::jobs,
	 "delimiter|d=s" => \$opt::d,
	 "max-chars|s=i" => \$opt::max_chars,
	 "arg-file|a=s" => \@opt::a,
	 "no-run-if-empty|r" => \$opt::r,
	 "replace|i:s" => \$opt::i,
	 "E=s" => \$opt::eof,
	 "eof|e:s" => \$opt::eof,
	 "max-args|n=i" => \$opt::max_args,
	 "max-replace-args|N=i" => \$opt::max_replace_args,
	 "colsep|col-sep|C=s" => \$opt::colsep,
	 "help|h" => \$opt::help,
	 "L=f" => \$opt::L,
	 "max-lines|l:f" => \$opt::max_lines,
	 "interactive|p" => \$opt::interactive,
	 "verbose|t" => \$opt::verbose,
	 "version|V" => \$opt::version,
	 "minversion|min-version=i" => \$opt::minversion,
	 "show-limits|showlimits" => \$opt::show_limits,
	 "exit|x" => \$opt::x,
	 # Semaphore
	 "semaphore" => \$opt::semaphore,
	 "semaphoretimeout|st=i" => \$opt::semaphoretimeout,
	 "semaphorename|id=s" => \$opt::semaphorename,
	 "fg" => \$opt::fg,
	 "bg" => \$opt::bg,
	 "wait" => \$opt::wait,
	 # Shebang #!/usr/bin/parallel --shebang
	 "shebang|hashbang" => \$opt::shebang,
	 "internal-pipe-means-argfiles" => \$opt::internal_pipe_means_argfiles,
	 "Y" => \$opt::retired,
         "skip-first-line" => \$opt::skip_first_line,
	 "bug" => \$opt::bug,
	 "header=s" => \$opt::header,
	 "cat" => \$opt::cat,
	 "fifo" => \$opt::fifo,
	 "pipepart|pipe-part" => \$opt::pipepart,
	 "tee" => \$opt::tee,
	 "hgrp|hostgrp|hostgroup|hostgroups" => \$opt::hostgroups,
	);
}

sub get_options_from_array {
    # Run GetOptions on @array
    # Input:
    #   $array_ref = ref to @ARGV to parse
    #   @keep_only = Keep only these options
    # Uses:
    #   @ARGV
    # Returns:
    #   true if parsing worked
    #   false if parsing failed
    #   @$array_ref is changed
    my ($array_ref, @keep_only) = @_;
    if(not @$array_ref) {
	# Empty array: No need to look more at that
	return 1;
    }
    # A bit of shuffling of @ARGV needed as GetOptionsFromArray is not
    # supported everywhere
    my @save_argv;
    my $this_is_ARGV = (\@::ARGV == $array_ref);
    if(not $this_is_ARGV) {
	@save_argv = @::ARGV;
	@::ARGV = @{$array_ref};
    }
    # If @keep_only set: Ignore all values except @keep_only
    my %options = options_hash();
    if(@keep_only) {
	my (%keep,@dummy);
	@keep{@keep_only} = @keep_only;
	for my $k (grep { not $keep{$_} } keys %options) {
	    # Store the value of the option in @dummy
	    $options{$k} = \@dummy;
	}
    }
    my $retval = GetOptions(%options);
    if(not $this_is_ARGV) {
	@{$array_ref} = @::ARGV;
	@::ARGV = @save_argv;
    }
    return $retval;
}

sub parse_options {
    # Returns: N/A
    init_globals();
    @ARGV = read_options();

    # no-* overrides *
    if($opt::nokeeporder) { $opt::keeporder = undef; }

    if(@opt::v) { $Global::verbose = $#opt::v+1; } # Convert -v -v to v=2
    if($opt::bug) { ::die_bug("test-bug"); }
    $Global::debug = $opt::D;
    $Global::shell = $ENV{'PARALLEL_SHELL'} || parent_shell($$)
	|| $ENV{'SHELL'} || "/bin/sh";
    $Global::cshell = $Global::shell =~ m:/csh:;
    if(defined $opt::X) { $Global::ContextReplace = 1; }
    if(defined $opt::silent) { $Global::verbose = 0; }
    if(defined $opt::null) { $/ = "\0"; }
    if(defined $opt::d) { $/ = unquote_printf($opt::d) }
    if(defined $opt::tagstring) {
	$opt::tagstring = unquote_printf($opt::tagstring);
    }
    if(defined $opt::interactive) { $Global::interactive = $opt::interactive; }
    if(defined $opt::q) { $Global::quoting = 1; }
    if(defined $opt::r) { $Global::ignore_empty = 1; }
    if(defined $opt::verbose) { $Global::stderr_verbose = 1; }
    parse_replacement_string_options();
    if(defined $opt::eof) { $Global::end_of_file_string = $opt::eof; }
    if(defined $opt::max_args) {
	$Global::max_number_of_args = $opt::max_args;
    }
    if(defined $opt::timeout) {
	$Global::timeoutq = TimeoutQueue->new($opt::timeout);
    }
    if(defined $opt::tmpdir) { $ENV{'TMPDIR'} = $opt::tmpdir; }
    $ENV{'PARALLEL_RSYNC_OPTS'} = $opt::rsync_opts ||
	$ENV{'PARALLEL_RSYNC_OPTS'} || '-rlDzR';
    $opt::nice ||= 0;
    if(defined $opt::help) { usage(); exit(0); }
    if(defined $opt::sqlandworker) {
	$opt::sqlmaster = $opt::sqlworker = $opt::sqlandworker;
    }
    if(defined $opt::tmuxpane) { $opt::tmux = $opt::tmuxpane; }
    if(defined $opt::colsep) { $Global::trim = 'lr'; }
    if(defined $opt::header) {
	$opt::colsep = defined $opt::colsep ? $opt::colsep : "\t";
    }
    if(defined $opt::trim) { $Global::trim = $opt::trim; }
    if(defined $opt::arg_sep) { $Global::arg_sep = $opt::arg_sep; }
    if(defined $opt::arg_file_sep) {
	$Global::arg_file_sep = $opt::arg_file_sep;
    }
    if(defined $opt::number_of_cpus) {
	print SSHLogin::no_of_cpus(),"\n"; wait_and_exit(0);
    }
    if(defined $opt::number_of_cores) {
        print SSHLogin::no_of_cores(),"\n"; wait_and_exit(0);
    }
    if(defined $opt::max_line_length_allowed) {
        print Limits::Command::real_max_length(),"\n"; wait_and_exit(0);
    }
    if(defined $opt::version) { version(); wait_and_exit(0); }
    if(defined $opt::citation) { citation(); wait_and_exit(0); }
    if(defined $opt::record_env) { record_env(); wait_and_exit(0); }
    if(defined $opt::show_limits) { show_limits(); }
    if(@opt::sshlogin) { @Global::sshlogin = @opt::sshlogin; }
    if(@opt::sshloginfile) { read_sshloginfiles(@opt::sshloginfile); }
    if(@opt::return) { push @Global::ret_files, @opt::return; }
    if($opt::transfer) {
	push @Global::transfer_files, $opt::i || $opt::I || "{}";
    }
    push @Global::transfer_files, @opt::transfer_files;
    if(not defined $opt::recstart and
       not defined $opt::recend) { $opt::recend = "\n"; }
    $Global::blocksize = multiply_binary_prefix($opt::blocksize || "1M");
    if($Global::blocksize > 2**31-1 and not $opt::pipepart) {
	warning("--blocksize >= 2G causes problems. Using 2G-1.");
	$Global::blocksize = 2**31-1;
    }
    if($^O eq "cygwin" and
       ($opt::pipe or $opt::pipepart or $opt::roundrobin)
       and $Global::blocksize > 65535) {
	warning("--blocksize >= 64K causes problems on Cygwin.");
    }
    $opt::memfree = multiply_binary_prefix($opt::memfree);
    check_invalid_option_combinations();
    if((defined $opt::fifo or defined $opt::cat)
       and not $opt::pipepart) {
	$opt::pipe = 1;
    }
    if(defined $opt::minversion) {
	print $Global::version,"\n";
	if($Global::version < $opt::minversion) {
	    wait_and_exit(255);
	} else {
	    wait_and_exit(0);
	}
    }
    if(not defined $opt::delay) {
	# Set --delay to --sshdelay if not set
	$opt::delay = $opt::sshdelay;
    }
    if($opt::compress_program) {
	$opt::compress = 1;
	$opt::decompress_program ||= $opt::compress_program." -dc";
    }

    if(defined $opt::results) {
	# Is the output a dir or CSV-file?
	if($opt::results =~ /\.csv$/i) {
	    # CSV with , as separator
	    $Global::csv = ",";
	    $Global::membuffer ||= 1;
	} elsif($opt::results =~ /\.tsv$/i) {
	    # CSV with TAB as separator
	    $Global::csv = "\t";
	    $Global::membuffer ||= 1;
	}
    }
    if($opt::compress) {
	my ($compress, $decompress) = find_compression_program();
	$opt::compress_program ||= $compress;
	$opt::decompress_program ||= $decompress;
	if(($opt::results and not $Global::csv) or $opt::files) {
	    # No need for decompressing
	    $opt::decompress_program = "cat >/dev/null";
	}
    }
    if(defined $opt::dryrun) {
	# Force grouping due to bug #51039: --dry-run --timeout 3600 -u breaks
	$opt::ungroup = 0;
	$opt::group = 1;
    }
    if(defined $opt::nonall) {
	# Append a dummy empty argument if there are no arguments
	# on the command line to avoid reading from STDIN.
	# arg_sep = random 50 char
	# \0 => nothing (not the empty string)
	$Global::arg_sep = join "",
	map { (0..9,"a".."z","A".."Z")[rand(62)] } (1..50);
	push @ARGV, $Global::arg_sep, "\0";
    }
    if(defined $opt::tee) {
	if(not defined $opt::jobs) {
	    $opt::jobs = 0;
	}
    }
    if(defined $opt::tty) {
        # Defaults for --tty: -j1 -u
        # Can be overridden with -jXXX -g
        if(not defined $opt::jobs) {
            $opt::jobs = 1;
        }
        if(not defined $opt::group) {
            $opt::ungroup = 1;
        }
    }
    if(@opt::trc) {
        push @Global::ret_files, @opt::trc;
	if(not @Global::transfer_files) {
	    # Defaults to --transferfile {}
	    push @Global::transfer_files, $opt::i || $opt::I || "{}";
	}
        $opt::cleanup = 1;
    }
    if(defined $opt::max_lines) {
	if($opt::max_lines eq "-0") {
	    # -l -0 (swallowed -0)
	    $opt::max_lines = 1;
	    $opt::null = 1;
	    $/ = "\0";
	} elsif ($opt::max_lines == 0) {
	    # If not given (or if 0 is given) => 1
	    $opt::max_lines = 1;
	}
	$Global::max_lines = $opt::max_lines;
	if(not $opt::pipe) {
	    # --pipe -L means length of record - not max_number_of_args
	    $Global::max_number_of_args ||= $Global::max_lines;
	}
    }

    # Read more than one arg at a time (-L, -N)
    if(defined $opt::L) {
	$Global::max_lines = $opt::L;
	if(not $opt::pipe) {
	    # --pipe -L means length of record - not max_number_of_args
	    $Global::max_number_of_args ||= $Global::max_lines;
	}
    }
    if(defined $opt::max_replace_args) {
	$Global::max_number_of_args = $opt::max_replace_args;
	$Global::ContextReplace = 1;
    }
    if((defined $opt::L or defined $opt::max_replace_args)
       and
       not ($opt::xargs or $opt::m)) {
	$Global::ContextReplace = 1;
    }
    if(defined $opt::tag and not defined $opt::tagstring) {
	# Default = {}
	$opt::tagstring = $Global::parensleft.$Global::parensright;
    }
    if(grep /^$Global::arg_sep\+?$|^$Global::arg_file_sep\+?$/o, @ARGV) {
        # Deal with ::: :::+ :::: and ::::+
        @ARGV = read_args_from_command_line();
    }
    parse_semaphore();

    if(defined $opt::eta) { $opt::progress = $opt::eta; }
    if(defined $opt::bar) { $opt::progress = $opt::bar; }
    citation_notice();

    parse_halt();
    parse_sshlogin();

    if(remote_hosts() and ($opt::X or $opt::m or $opt::xargs)) {
        # As we do not know the max line length on the remote machine
        # long commands generated by xargs may fail
        # If $opt::max_replace_args is set, it is probably safe
        ::warning("Using -X or -m with --sshlogin may fail.");
    }

    if(not defined $opt::jobs) { $opt::jobs = "100%"; }
    open_joblog();
    open_csv();
    if($opt::sqlmaster or $opt::sqlworker) {
	$Global::sql = SQL->new($opt::sqlmaster || $opt::sqlworker);
    }
    if($opt::sqlworker) { $Global::membuffer ||= 1; }
}

sub check_invalid_option_combinations {
    if(defined $opt::timeout and
       $opt::timeout !~ /^\d+(\.\d+)?%?$|^(\d+(\.\d+)?[dhms])+$/i) {
	::error("--timeout must be seconds or percentage.");
	wait_and_exit(255);
    }
    if(defined $opt::fifo and defined $opt::cat) {
	::error("--fifo cannot be combined with --cat.");
	::wait_and_exit(255);
    }
    if(defined $opt::retries and defined $opt::roundrobin) {
	::error("--retries cannot be combined with --roundrobin.");
	::wait_and_exit(255);
    }
    if(defined $opt::pipepart and
       (defined $opt::L or defined $opt::max_lines
	or defined $opt::max_replace_args)) {
	::error("--pipepart is incompatible with --max-replace-args, ".
		"--max-lines, and -L.");
	wait_and_exit(255);
    }
    if(defined $opt::group and $opt::ungroup) {
	::error("--group cannot be combined with --ungroup.");
	::wait_and_exit(255);
    }
    if(defined $opt::group and $opt::linebuffer) {
	::error("--group cannot be combined with --line-buffer.");
	::wait_and_exit(255);
    }
    if(defined $opt::ungroup and $opt::linebuffer) {
	::error("--ungroup cannot be combined with --line-buffer.");
	::wait_and_exit(255);
    }
    if(defined $opt::tollef and not $opt::gnu) {
       ::error("--tollef has been retired.",
	       "Remove --tollef or use --gnu to override --tollef.");
       ::wait_and_exit(255);
    }
    if(defined $opt::retired) {
	    ::error("-g has been retired. Use --group.",
		    "-B has been retired. Use --bf.",
		    "-T has been retired. Use --tty.",
		    "-U has been retired. Use --er.",
		    "-W has been retired. Use --wd.",
		    "-Y has been retired. Use --shebang.",
		    "-H has been retired. Use --halt.",
		    "--sql has been retired. Use --sqlmaster.",
		    "--ctrlc has been retired.",
		    "--noctrlc has been retired.");
            ::wait_and_exit(255);
    }
}

sub init_globals {
    # Defaults:
    $Global::version = 20171122;
    $Global::progname = 'parallel';
    $Global::infinity = 2**31;
    $Global::debug = 0;
    $Global::verbose = 0;
    $Global::quoting = 0;
    $Global::total_completed = 0;
    # Read only table with default --rpl values
    %Global::replace =
	(
	 '{}'   => '',
	 '{#}'  => '1 $_=$job->seq()',
	 '{%}'  => '1 $_=$job->slot()',
	 '{/}'  => 's:.*/::',
	 '{//}' =>
	 ('$Global::use{"File::Basename"} ||= eval "use File::Basename; 1;"; '.
	  '$_ = dirname($_);'),
	 '{/.}' => 's:.*/::; s:\.[^/.]+$::;',
	 '{.}'  => 's:\.[^/.]+$::',
	);
    %Global::plus =
	(
	 # {} = {+/}/{/}
	 #    = {.}.{+.}     = {+/}/{/.}.{+.}
	 #    = {..}.{+..}   = {+/}/{/..}.{+..}
	 #    = {...}.{+...} = {+/}/{/...}.{+...}
	 '{+/}' => 's:/[^/]*$::',
	 '{+.}' => 's:.*\.::',
	 '{+..}' => 's:.*\.([^.]*\.):$1:',
	 '{+...}' => 's:.*\.([^.]*\.[^.]*\.):$1:',
	 '{..}' => 's:\.[^/.]+$::; s:\.[^/.]+$::',
	 '{...}' => 's:\.[^/.]+$::; s:\.[^/.]+$::; s:\.[^/.]+$::',
	 '{/..}' => 's:.*/::; s:\.[^/.]+$::; s:\.[^/.]+$::',
	 '{/...}' => 's:.*/::; s:\.[^/.]+$::; s:\.[^/.]+$::; s:\.[^/.]+$::',
	 '{choose_k}' => 'for $t (2..$#arg){ if($arg[$t-1] ge $arg[$t]) { skip() } }',
	 # {##} = number of jobs
	 '{##}' => '$_=total_jobs()',
	 # Bash ${a:-myval}
	 '{:-([^}]+?)}' => '$_ ||= $$1',
	 # Bash ${a:2}
	 '{:(\d+?)}' => 'substr($_,0,$$1) = ""',
	 # Bash ${a:2:3}
	 '{:(\d+?):(\d+?)}' => '$_ = substr($_,$$1,$$2);',
	 # Bash ${a#bc}
	 '{#([^#}][^}]*?)}' => 's/^$$1//;',
	 # Bash ${a%def}
	 '{%([^}]+?)}' => 's/$$1$//;',
	 # Bash ${a/def/ghi} ${a/def/}
	 '{/([^}]+?)/([^}]*?)}' => 's/$$1/$$2/;',
	 # Bash ${a^a}
	 '{^([^}]+?)}' => 's/^($$1)/uc($1)/e;',
	 # Bash ${a^^a}
	 '{^^([^}]+?)}' => 's/($$1)/uc($1)/eg;',
	 # Bash ${a,A}
	 '{,([^}]+?)}' => 's/^($$1)/lc($1)/e;',
	 # Bash ${a,,A}
	 '{,,([^}]+?)}' => 's/($$1)/lc($1)/eg;',
	);
    # Modifiable copy of %Global::replace
    %Global::rpl = %Global::replace;
    $/ = "\n";
    $Global::ignore_empty = 0;
    $Global::interactive = 0;
    $Global::stderr_verbose = 0;
    $Global::default_simultaneous_sshlogins = 9;
    $Global::exitstatus = 0;
    $Global::arg_sep = ":::";
    $Global::arg_file_sep = "::::";
    $Global::trim = 'n';
    $Global::max_jobs_running = 0;
    $Global::job_already_run = '';
    $ENV{'TMPDIR'} ||= "/tmp";
    if(not $ENV{HOME}) {
	# $ENV{HOME} is sometimes not set if called from PHP
	::warning("\$HOME not set. Using /tmp.");
	$ENV{HOME} = "/tmp";
    }
    # no warnings to allow for undefined $XDG_*
    no warnings 'uninitialized';
    # $xdg_config_home is needed to make env_parallel.fish stop complaining
    my $xdg_config_home = $ENV{'XDG_CONFIG_HOME'};
    # config_dirs = $PARALLEL_HOME, $XDG_CONFIG_HOME/parallel,
    #   $(each XDG_CONFIG_DIRS)/parallel, $HOME/.parallel
    # Keep only dirs that exist
    @Global::config_dirs =
	(grep { -d $_ }
	 $ENV{'PARALLEL_HOME'},
	 (map { "$_/parallel" }
	  $xdg_config_home,
	  split /:/, $ENV{'XDG_CONFIG_DIRS'}),
	 $ENV{'HOME'} . "/.parallel");
    # Use first dir as config dir
    $Global::config_dir = $Global::config_dirs[0] ||
	$ENV{'HOME'} . "/.parallel";
    # cache_dirs = $PARALLEL_HOME, $XDG_CACHE_HOME/parallel,
    # Keep only dirs that exist
    @Global::cache_dirs =
	(grep { -d $_ }
	 $ENV{'PARALLEL_HOME'}, $ENV{'XDG_CACHE_HOME'}."/parallel");
    $Global::cache_dir = $Global::cache_dirs[0] ||
	$ENV{'HOME'} . "/.parallel";
}

sub parse_halt {
    # $opt::halt flavours
    # Uses:
    #   $opt::halt
    #   $Global::halt_when
    #   $Global::halt_fail
    #   $Global::halt_success
    #   $Global::halt_pct
    #   $Global::halt_count
    if(defined $opt::halt) {
	my %halt_expansion = (
	    "0" => "never",
	    "1" => "soon,fail=1",
	    "2" => "now,fail=1",
	    "-1" => "soon,success=1",
	    "-2" => "now,success=1",
	);
	# Expand -2,-1,0,1,2 into long form
	$opt::halt = $halt_expansion{$opt::halt} || $opt::halt;
	# --halt 5% == --halt soon,fail=5%
	$opt::halt =~ s/^(\d+)%$/soon,fail=$1%/;
	# Split: soon,fail=5%
	my ($when,$fail_success,$pct_count) = split /[,=]/, $opt::halt;
	if(not grep { $when eq $_ } qw(never soon now)) {
	    ::error("--halt must have 'never', 'soon', or 'now'.");
	    ::wait_and_exit(255);
	}
	$Global::halt_when = $when;
	if($when ne "never") {
	    if($fail_success eq "fail") {
		$Global::halt_fail = 1;
	    } elsif($fail_success eq "success") {
		$Global::halt_success = 1;
	    } elsif($fail_success eq "done") {
		$Global::halt_done = 1;
	    } else {
		::error("--halt $when must be followed by ,success or ,fail.");
		::wait_and_exit(255);
	    }
	    if($pct_count =~ /^(\d+)%$/) {
		$Global::halt_pct = $1/100;
	    } elsif($pct_count =~ /^(\d+)$/) {
		$Global::halt_count = $1;
	    } else {
		::error("--halt $when,$fail_success ".
			"must be followed by ,number or ,percent%.");
		::wait_and_exit(255);
	    }
	}
    }
}

sub parse_replacement_string_options {
    # Deal with --rpl
    # Uses:
    #   %Global::rpl
    #   $Global::parensleft
    #   $Global::parensright
    #   $opt::parens
    #   $Global::parensleft
    #   $Global::parensright
    #   $opt::plus
    #   %Global::plus
    #   $opt::I
    #   $opt::U
    #   $opt::i
    #   $opt::basenamereplace
    #   $opt::dirnamereplace
    #   $opt::seqreplace
    #   $opt::slotreplace
    #   $opt::basenameextensionreplace

    sub rpl {
	# Modify %Global::rpl
	# Replace $old with $new
	my ($old,$new) =  @_;
	if($old ne $new) {
	    $Global::rpl{$new} = $Global::rpl{$old};
	    delete $Global::rpl{$old};
	}
    }
    my $parens = "{==}";
    if(defined $opt::parens) { $parens = $opt::parens; }
    my $parenslen = 0.5*length $parens;
    $Global::parensleft = substr($parens,0,$parenslen);
    $Global::parensright = substr($parens,$parenslen);
    if(defined $opt::plus) { %Global::rpl = (%Global::plus,%Global::rpl); }
    if(defined $opt::I) { rpl('{}',$opt::I); }
    if(defined $opt::i and $opt::i) { rpl('{}',$opt::i); }
    if(defined $opt::U) { rpl('{.}',$opt::U); }
    if(defined $opt::basenamereplace) { rpl('{/}',$opt::basenamereplace); }
    if(defined $opt::dirnamereplace) { rpl('{//}',$opt::dirnamereplace); }
    if(defined $opt::seqreplace) { rpl('{#}',$opt::seqreplace); }
    if(defined $opt::slotreplace) { rpl('{%}',$opt::slotreplace); }
    if(defined $opt::basenameextensionreplace) {
       rpl('{/.}',$opt::basenameextensionreplace);
    }
    for(@opt::rpl) {
	# Create $Global::rpl entries for --rpl options
	# E.g: "{..} s:\.[^.]+$:;s:\.[^.]+$:;"
	my ($shorthand,$long) = split/ /,$_,2;
	$Global::rpl{$shorthand} = $long;
    }
}

sub parse_semaphore {
    # Semaphore defaults
    # Must be done before computing number of processes and max_line_length
    # because when running as a semaphore GNU Parallel does not read args
    # Uses:
    #   $opt::semaphore
    #   $Global::semaphore
    #   $opt::semaphoretimeout
    #   $Semaphore::timeout
    #   $opt::semaphorename
    #   $Semaphore::name
    #   $opt::fg
    #   $Semaphore::fg
    #   $opt::wait
    #   $Semaphore::wait
    #   $opt::bg
    #   @opt::a
    #   @Global::unget_argv
    #   $Global::default_simultaneous_sshlogins
    #   $opt::jobs
    #   $Global::interactive
    $Global::semaphore ||= ($0 =~ m:(^|/)sem$:); # called as 'sem'
    if(defined $opt::semaphore) { $Global::semaphore = 1; }
    if(defined $opt::semaphoretimeout) { $Global::semaphore = 1; }
    if(defined $opt::semaphorename) { $Global::semaphore = 1; }
    if(defined $opt::fg and not $opt::tmux and not $opt::tmuxpane) {
	$Global::semaphore = 1;
    }
    if(defined $opt::bg) { $Global::semaphore = 1; }
    if(defined $opt::wait and not $opt::sqlmaster) {
	$Global::semaphore = 1; @ARGV = "true";
    }
    if($Global::semaphore) {
	if(@opt::a) {
	    # A semaphore does not take input from neither stdin nor file
	    ::error("A semaphore does not take input from neither stdin nor a file\n");
	    ::wait_and_exit(255);
	}
	@opt::a = ("/dev/null");
	# Append a dummy empty argument
	# \0 => nothing (not the empty string)
        push(@Global::unget_argv, [Arg->new("\0")]);
        $Semaphore::timeout = $opt::semaphoretimeout || 0;
        if(defined $opt::semaphorename) {
            $Semaphore::name = $opt::semaphorename;
        } else {
            local $/ = "\n";
            $Semaphore::name = `tty`;
            chomp $Semaphore::name;
        }
        $Semaphore::fg = $opt::fg;
        $Semaphore::wait = $opt::wait;
        $Global::default_simultaneous_sshlogins = 1;
        if(not defined $opt::jobs) {
            $opt::jobs = 1;
        }
	if($Global::interactive and $opt::bg) {
	    ::error("Jobs running in the ".
		    "background cannot be interactive.");
            ::wait_and_exit(255);
	}
    }
}

sub record_env {
    # Record current %ENV-keys in $PARALLEL_HOME/ignored_vars
    # Returns: N/A
    my $ignore_filename = $Global::config_dir . "/ignored_vars";
    if(open(my $vars_fh, ">", $ignore_filename)) {
	print $vars_fh map { $_,"\n" } keys %ENV;
    } else {
	::error("Cannot write to $ignore_filename.");
	::wait_and_exit(255);
    }
}

sub open_joblog {
    # Open joblog as specified by --joblog
    # Uses:
    #   $opt::resume
    #   $opt::resume_failed
    #   $opt::joblog
    #   $opt::results
    #   $Global::job_already_run
    #   %Global::fd
    my $append = 0;
    if(($opt::resume or $opt::resume_failed)
       and
       not ($opt::joblog or $opt::results)) {
        ::error("--resume and --resume-failed require --joblog or --results.");
	::wait_and_exit(255);
    }
    if(defined $opt::joblog and $opt::joblog =~ s/^\+//) {
	$append = 1;
    }
    if($opt::joblog
       and
       ($opt::sqlmaster
	or
	not $opt::sqlworker)) {
	if($opt::resume || $opt::resume_failed || $opt::retry_failed) {
	    if(open(my $joblog_fh, "<", $opt::joblog)) {
		# Read the joblog
		# If there is a header: Open as append later
		$append = <$joblog_fh>;
		my $joblog_regexp;
		if($opt::retry_failed) {
		    # Make a regexp that only matches commands with exit+signal=0
		    # 4 host 1360490623.067 3.445 1023 1222 0 0 command
		    $joblog_regexp='^(\d+)(?:\t[^\t]+){5}\t0\t0\t';
		    my @group;
		    {
			local $/ = "\n";
			while(<$joblog_fh>) {
			    if(/$joblog_regexp/o) {
				# This is 30% faster than set_job_already_run($1);
				vec($Global::job_already_run,($1||0),1) = 1;
				$Global::total_completed++;
				$group[$1-1] = "true";
			    } elsif(/(\d+)\s+\S+(\s+[-0-9.]+){6}\s+(.*)$/) {
				# Grab out the command
				$group[$1-1] = $3;
			    } else {
				chomp;
				::error("Format of '$opt::joblog' is wrong: $_");
				::wait_and_exit(255);
			    }
			}
		    }
		    if(@group) {
			my ($outfh,$name) = ::tmpfile(SUFFIX => ".arg");
			unlink($name);
			# Put args into argfile
			if(grep /\0/, @group) {
			    # force --null to deal with \n in commandlines
			    ::warning("Command lines contain newline. Forcing --null.");
			    $opt::null = 1;
			    $/ = "\0";
			}
			# Replace \0 with '\n' as used in print_joblog()
			print $outfh map { s/\0/\n/g; $_,$/ } @group;
			seek $outfh, 0, 0;
			exit_if_disk_full();
			# Set filehandle to -a
			@opt::a = ($outfh);
		    }
		    # Remove $command (so -a is run)
		    @ARGV = ();
		}
		if($opt::resume || $opt::resume_failed) {
		    if($opt::resume_failed) {
			# Make a regexp that only matches commands with exit+signal=0
			# 4 host 1360490623.067 3.445 1023 1222 0 0 command
			$joblog_regexp='^(\d+)(?:\t[^\t]+){5}\t0\t0\t';
		    } else {
			# Just match the job number
			$joblog_regexp='^(\d+)';
		    }
		    while(<$joblog_fh>) {
			if(/$joblog_regexp/o) {
			    # This is 30% faster than set_job_already_run($1);
			    vec($Global::job_already_run,($1||0),1) = 1;
			    $Global::total_completed++;
			} elsif(not /\d+\s+[^\s]+\s+([-0-9.]+\s+){6}/) {
			    ::error("Format of '$opt::joblog' is wrong: $_");
			    ::wait_and_exit(255);
			}
		    }
		}
		close $joblog_fh;
	    }
	}
	if($append) {
	    # Append to joblog
	    if(not open($Global::joblog, ">>", $opt::joblog)) {
		::error("Cannot append to --joblog $opt::joblog.");
		::wait_and_exit(255);
	    }
	} else {
	    if($opt::dryrun) {
		# Do not write to joblog in a dry-run
		if(not open($Global::joblog, ">", "/dev/null")) {
		    ::error("Cannot write to --joblog $opt::joblog.");
		    ::wait_and_exit(255);
		}
	    } elsif($opt::joblog eq "-") {
		# Use STDOUT as joblog
		$Global::joblog = $Global::fd{1};
	    } elsif(not open($Global::joblog, ">", $opt::joblog)) {
		# Overwrite the joblog
		::error("Cannot write to --joblog $opt::joblog.");
		::wait_and_exit(255);
	    }
	    print $Global::joblog
		join("\t", "Seq", "Host", "Starttime", "JobRuntime",
		     "Send", "Receive", "Exitval", "Signal", "Command"
		). "\n";
	}
    }
}

sub open_csv {
    if($opt::results) {
	# Output as CSV/TSV
	if($opt::results eq "-.csv"
	   or
	   $opt::results eq "-.tsv") {
	    # Output as CSV/TSV on stdout
	    open $Global::csv_fh, ">&", "STDOUT" or
		::die_bug("Can't dup STDOUT in csv: $!");
	    # Do not print any other output to STDOUT
	    # by forcing all other output to /dev/null
	    open my $fd, ">", "/dev/null" or
		::die_bug("Can't >/dev/null in csv: $!");
	    $Global::fd{1} = $fd;
	    $Global::fd{2} = $fd;
	} elsif($Global::csv) {
	    if(not open($Global::csv_fh,">",$opt::results)) {
		::error("Cannot open results file `$opt::results': ".
			"$!.");
		wait_and_exit(255);
	    }
	}
    }
}

sub find_compression_program {
    # Find a fast compression program
    # Returns:
    #   $compress_program = compress program with options
    #   $decompress_program = decompress program with options

    # Search for these. Sorted by speed on 128 core

    # seq 120000000|shuf > 1gb &
    # apt-get update
    # apt install make g++ htop
    # wget -O - pi.dk/3 | bash
    # apt install zstd clzip liblz4-tool lzop pigz pxz gzip plzip pbzip2 lzma xz-utils lzip bzip2 lbzip2 lrzip pixz
    # git clone https://github.com/facebook/zstd.git
    # (cd zstd/contrib/pzstd; make -j; cp pzstd /usr/local/bin)
    # echo 'lrzip -L $((-$1))'  >/usr/local/bin/lrz
    # chmod +x /usr/local/bin/lrz
    # wait
    # onethread="zstd clzip lz4 lzop gzip lzma xz bzip2"
    # multithread="pzstd pigz pxz plzip pbzip2 lzip lbzip2 lrz pixz"
    # parallel --shuf -j1  --joblog jl-m --arg-sep ,  parallel --compress-program \'{3}" "-{2}\' cat ::: 1gb '>'/dev/null , 1 2 3 ,  {1..3} , $multithread
    # parallel --shuf -j50% --delay 1  --joblog jl-s --arg-sep ,  parallel --compress-program \'{3}" "-{2}\' cat ::: 1gb '>'/dev/null , 1 2 3 ,  {1..3} , $onethread
    # sort -nk4 jl-?

    # 1-core:
    # 2-cores: pzstd zstd lz4 lzop pigz gzip lbzip2 pbzip2 lrz bzip2 lzma pxz plzip xz lzip clzip
    # 4-cores:
    # 8-cores: pzstd lz4 zstd pigz lzop lbzip2 pbzip2 gzip lzip lrz plzip pxz bzip2 lzma xz clzip
    # 16-cores: pzstd lz4 pigz lzop lbzip2 pbzip2 plzip lzip lrz pxz gzip lzma xz bzip2
    # 32-cores: pzstd lbzip2 pbzip2 zstd pigz lz4 lzop plzip lzip lrz gzip pxz lzma bzip2 xz clzip
    # 64-cores: pzstd lbzip2 pbzip2 pigz zstd pixz lz4 plzip lzop lzip lrz gzip pxz lzma bzip2 xz clzip
    # 128-core: pzstd lbzip2 pbzip2 zstd pixz lz4 pigz lzop plzip lzip gzip lrz pxz bzip2 lzma xz clzip

    my @prg = qw(pzstd lbzip2 pbzip2 zstd pixz lz4 pigz lzop plzip lzip gzip
                 lrz pxz bzip2 lzma xz clzip);
    for my $p (@prg) {
	if(which($p)) {
	    return ("$p -c -1","$p -dc");
	}
    }
    # Fall back to cat
    return ("cat","cat");
}

sub read_options {
    # Read options from command line, profile and $PARALLEL
    # Uses:
    #   $opt::shebang_wrap
    #   $opt::shebang
    #   @ARGV
    #   $opt::plain
    #   @opt::profile
    #   $ENV{'HOME'}
    #   $ENV{'PARALLEL'}
    # Returns:
    #   @ARGV_no_opt = @ARGV without --options

    # This must be done first as this may exec myself
    if(defined $ARGV[0] and ($ARGV[0] =~ /^--shebang/ or
			     $ARGV[0] =~ /^--shebang-?wrap/ or
			     $ARGV[0] =~ /^--hashbang/)) {
        # Program is called from #! line in script
	# remove --shebang-wrap if it is set
        $opt::shebang_wrap = ($ARGV[0] =~ s/^--shebang-?wrap *//);
	# remove --shebang if it is set
	$opt::shebang = ($ARGV[0] =~ s/^--shebang *//);
	# remove --hashbang if it is set
        $opt::shebang .= ($ARGV[0] =~ s/^--hashbang *//);
	if($opt::shebang) {
	    my $argfile = shell_quote_scalar(pop @ARGV);
	    # exec myself to split $ARGV[0] into separate fields
	    exec "$0 --skip-first-line -a $argfile @ARGV";
	}
	if($opt::shebang_wrap) {
            my @options;
	    my @parser;
	    if ($^O eq 'freebsd') {
		# FreeBSD's #! puts different values in @ARGV than Linux' does.
		my @nooptions = @ARGV;
		get_options_from_array(\@nooptions);
		while($#ARGV > $#nooptions) {
		    push @options, shift @ARGV;
		}
		while(@ARGV and $ARGV[0] ne ":::") {
		    push @parser, shift @ARGV;
		}
		if(@ARGV and $ARGV[0] eq ":::") {
		    shift @ARGV;
		}
	    } else {
		@options = shift @ARGV;
	    }
	    my $script = shell_quote_scalar(shift @ARGV);
	    # exec myself to split $ARGV[0] into separate fields
	    exec "$0 --internal-pipe-means-argfiles @options @parser $script ".
		"::: @ARGV";
	}
    }
    if($ARGV[0] =~ / --shebang(-?wrap)? /) {
	::warning("--shebang and --shebang-wrap must be the first argument.\n");
    }

    Getopt::Long::Configure("bundling","require_order");
    my @ARGV_copy = @ARGV;
    my @ARGV_orig = @ARGV;
    # Check if there is a --profile to set @opt::profile
    get_options_from_array(\@ARGV_copy,"profile|J=s","plain") || die_usage();
    my @ARGV_profile = ();
    my @ARGV_env = ();
    if(not $opt::plain) {
	# Add options from $PARALLEL_HOME/config and other profiles
	my @config_profiles = (
	    "/etc/parallel/config",
	    (map { "$_/config" } @Global::config_dirs),
	    $ENV{'HOME'}."/.parallelrc");
	my @profiles = @config_profiles;
	if(@opt::profile) {
	    # --profile overrides default profiles
	    @profiles = ();
	    for my $profile (@opt::profile) {
		# Look for the $profile in . and @Global::config_dirs
		push @profiles, grep { -r $_ }
		    map { "$_/$profile" } ".", @Global::config_dirs;
	    }
	}
	for my $profile (@profiles) {
	    if(-r $profile) {
                local $/ = "\n";
		open (my $in_fh, "<", $profile) ||
		    ::die_bug("read-profile: $profile");
		while(<$in_fh>) {
		    /^\s*\#/ and next;
		    chomp;
		    push @ARGV_profile, shell_words($_);
		}
		close $in_fh;
	    } else {
		if(grep /^$profile$/, @config_profiles) {
		    # config file is not required to exist
		} else {
		    ::error("$profile not readable.");
		    wait_and_exit(255);
		}
	    }
	}
	# Add options from shell variable $PARALLEL
	if($ENV{'PARALLEL'}) {
	    @ARGV_env = shell_words($ENV{'PARALLEL'});
	}
    }
    Getopt::Long::Configure("bundling","require_order");
    get_options_from_array(\@ARGV_profile) || die_usage();
    get_options_from_array(\@ARGV_env) || die_usage();
    get_options_from_array(\@ARGV) || die_usage();
    # What were the options given on the command line?
    # Used to start --sqlworker
    my $ai = arrayindex(\@ARGV_orig, \@ARGV);
    @Global::options_in_argv = @ARGV_orig[0..$ai-1];
    # Prepend non-options to @ARGV (such as commands like 'nice')
    unshift @ARGV, @ARGV_profile, @ARGV_env;
    return @ARGV;
}

sub arrayindex {
    # Similar to Perl's index function, but for arrays
    # Input:
    #   $arr_ref1 = ref to @array1 to search in
    #   $arr_ref2 = ref to @array2 to search for
    my ($arr_ref1,$arr_ref2) = @_;
    my $array1_as_string = join "", map { "\0".$_ } @$arr_ref1;
    my $array2_as_string = join "", map { "\0".$_ } @$arr_ref2;
    my $i = index($array1_as_string,$array2_as_string,0);
    if($i == -1) { return -1 }
    my @before = split /\0/, substr($array1_as_string,0,$i);
    return $#before;
}

sub read_args_from_command_line {
    # Arguments given on the command line after:
    #   ::: ($Global::arg_sep)
    #   :::: ($Global::arg_file_sep)
    #   :::+ ($Global::arg_sep with --link)
    #   ::::+ ($Global::arg_file_sep with --link)
    # Removes the arguments from @ARGV and:
    # - puts filenames into -a
    # - puts arguments into files and add the files to -a
    # - adds --linkinputsource with 0/1 for each -a depending on :::+/::::+
    # Input:
    #   @::ARGV = command option ::: arg arg arg :::: argfiles
    # Uses:
    #   $Global::arg_sep
    #   $Global::arg_file_sep
    #   $opt::internal_pipe_means_argfiles
    #   $opt::pipe
    #   @opt::a
    # Returns:
    #   @argv_no_argsep = @::ARGV without ::: and :::: and following args
    my @new_argv = ();
    for(my $arg = shift @ARGV; @ARGV; $arg = shift @ARGV) {
        if($arg eq $Global::arg_sep
	   or
	   $arg eq $Global::arg_sep."+"
	   or
	   $arg eq $Global::arg_file_sep
	   or
	   $arg eq $Global::arg_file_sep."+") {
	    my $group_sep = $arg; # This group of arguments is args or argfiles
	    my @group;
	    while(defined ($arg = shift @ARGV)) {
		if($arg eq $Global::arg_sep
		   or
		   $arg eq $Global::arg_sep."+"
		   or
		   $arg eq $Global::arg_file_sep
		   or
		   $arg eq $Global::arg_file_sep."+") {
		    # exit while loop if finding new separator
		    last;
		} else {
		    # If not hitting ::: :::+ :::: or ::::+
		    # Append it to the group
		    push @group, $arg;
		}
	    }
	    my $is_linked = ($group_sep =~ /\+$/) ? 1 : 0;
	    my $is_file = ($group_sep eq $Global::arg_file_sep
			   or
			   $group_sep eq $Global::arg_file_sep."+");
	    if($is_file) {
		# :::: / ::::+
		push @opt::linkinputsource, map { $is_linked } @group;
	    } else {
		# ::: / :::+
		push @opt::linkinputsource, $is_linked;
	    }
	    if($is_file
	       or ($opt::internal_pipe_means_argfiles and $opt::pipe)
		) {
		# Group of file names on the command line.
		# Append args into -a
		push @opt::a, @group;
	    } else {
		# Group of arguments on the command line.
		# Put them into a file.
		# Create argfile
		my ($outfh,$name) = ::tmpfile(SUFFIX => ".arg");
		unlink($name);
		# Put args into argfile
		print $outfh map { $_,$/ } @group;
		seek $outfh, 0, 0;
		exit_if_disk_full();
		# Append filehandle to -a
		push @opt::a, $outfh;
	    }
	    if(defined($arg)) {
		# $arg is ::: :::+ :::: or ::::+
		# so there is another group
		redo;
	    } else {
		# $arg is undef -> @ARGV empty
		last;
	    }
	}
	push @new_argv, $arg;
    }
    # Output: @ARGV = command to run with options
    return @new_argv;
}

sub cleanup {
    # Returns: N/A
    unlink keys %Global::unlink;
    map { rmdir $_ } keys %Global::unlink;
    if(@opt::basefile and $opt::cleanup) { cleanup_basefile(); }
    for(keys %Global::sshmaster) {
	# If 'ssh -M's are running: kill them
	kill "TERM", $_;
    }
}


sub __QUOTING_ARGUMENTS_FOR_SHELL__ {}


sub shell_quote {
    # Input:
    #   @strings = strings to be quoted
    # Output:
    #   @shell_quoted_strings = string quoted with \ as needed by the shell
    return wantarray ?
	(map { shell_quote_scalar($_) } @_)
	: (join" ",map { shell_quote_scalar($_) } @_);
}

sub shell_quote_scalar_rc {
    # Quote for the rc-shell
    my $a = $_[0];
    if(defined $a) {
	if(($a =~ s/'/''/g)
	   +
	   ($a =~ s/[\n\002-\011\013-\032\\\#\?\`\(\)\{\}\[\]\^\*\<\=\>\~\|\; \"\!\$\&\'\202-\377]+/'$&'/go)) {
	    # A string was replaced
	    # No need to test for "" or \0
	} elsif($a eq "") {
	    $a = "''";
	} elsif($a eq "\0") {
	    $a = "";
	}
    }
    return $a;
}

sub shell_quote_scalar_csh {
    # Quote for (t)csh
    my $a = $_[0];
    if(defined $a) {
	# $a =~ s/([\002-\011\013-\032\\\#\?\`\(\)\{\}\[\]\^\*\>\<\~\|\; \"\!\$\&\'\202-\377])/\\$1/g;
	# This is 1% faster than the above
	if(($a =~ s/[\002-\011\013-\032\\\#\?\`\(\)\{\}\[\]\^\*\<\=\>\~\|\; \"\!\$\&\'\202-\377]/\\$&/go)
	   +
	   # quote newline in csh as \\\n
	   ($a =~ s/[\n]/"\\\n"/go)) {
	    # A string was replaced
	    # No need to test for "" or \0
	} elsif($a eq "") {
	    $a = "''";
	} elsif($a eq "\0") {
	    $a = "";
	}
    }
    return $a;
}

sub shell_quote_scalar_default {
    # Quote for other shells
    my $a = $_[0];
    if(defined $a) {
	# zsh wants '=' quoted
	# Solaris sh wants ^ quoted.
	# $a =~ s/([\002-\011\013-\032\\\#\?\`\(\)\{\}\[\]\^\*\>\<\~\|\; \"\!\$\&\'\202-\377])/\\$1/g;
	# This is 1% faster than the above
	if(($a =~ s/[\002-\011\013-\032\\\#\?\`\(\)\{\}\[\]\^\*\<\=\>\~\|\; \"\!\$\&\'\202-\377]/\\$&/go)
	   +
	   # quote newline as '\n'
	   ($a =~ s/[\n]/'\n'/go)) {
	    # A string was replaced
	    # No need to test for "" or \0
	} elsif($a eq "") {
	    $a = "''";
	} elsif($a eq "\0") {
	    $a = "";
	}
    }
    return $a;
}

sub shell_quote_scalar {
    # Quote the string so the shell will not expand any special chars
    # Inputs:
    #   $string = string to be quoted
    # Returns:
    #   $shell_quoted = string quoted as needed by the shell

    # Speed optimization: Choose the correct shell_quote_scalar_*
    # and call that directly from now on
    no warnings 'redefine';
    if($Global::shell =~ m:(^|/)t?csh$:) {
	# (t)csh
	*shell_quote_scalar = \&shell_quote_scalar_csh;
    } elsif($Global::shell =~ m:(^|/)rc$:) {
	# rc-shell
	*shell_quote_scalar = \&shell_quote_scalar_rc;
    } else {
	# other shells
	*shell_quote_scalar = \&shell_quote_scalar_default;
    }
    # The sub is now redefined. Call it
    return shell_quote_scalar(@_);
}

sub shell_quote_file {
    # Quote the string so shell will not expand any special chars
    # and prepend ./ if needed
    # Input:
    #   $filename = filename to be shell quoted
    # Returns:
    #   $quoted_filename = filename quoted with \ and ./ if needed
    my $a = shell_quote_scalar(shift);
    if(defined $a) {
	if($a =~ m:^/: or $a =~ m:^\./:) {
	    # /abs/path or ./rel/path => skip
	} else {
	    # rel/path => ./rel/path
	    $a = "./".$a;
	}
    }
    return $a;
}

sub shell_words {
    # Input:
    #   $string = shell line
    # Returns:
    #   @shell_words = $string split into words as shell would do
    $Global::use{"Text::ParseWords"} ||= eval "use Text::ParseWords; 1;";
    return Text::ParseWords::shellwords(@_);
}

sub perl_quote_scalar {
    # Quote the string so perl's eval will not expand any special chars
    # Inputs:
    #   $string = string to be quoted
    # Returns:
    #   $shell_quoted = string quoted with \ as needed by perl's eval
    my $a = $_[0];
    if(defined $a) {
	$a =~ s/[\\\"\$\@]/\\$&/go;
    }
    return $a;
}

sub unquote_printf {
    # Convert \t \n \r \000 \0
    $_ = shift;
    s/\\t/\t/g;
    s/\\n/\n/g;
    s/\\r/\r/g;
    s/\\(\d\d\d)/eval 'sprintf "\\'.$1.'"'/ge;
    s/\\(\d)/eval 'sprintf "\\'.$1.'"'/ge;
    return $_;
}


sub __FILEHANDLES__ {}


sub save_stdin_stdout_stderr {
    # Remember the original STDIN, STDOUT and STDERR
    # and file descriptors opened by the shell (e.g. 3>/tmp/foo)
    # Uses:
    #   %Global::fd
    #   $Global::original_stderr
    #   $Global::original_stdin
    # Returns: N/A

    # TODO Disabled until we have an open3 that will take n filehandles
    # for my $fdno (1..61) {
    # # /dev/fd/62 and above are used by bash for <(cmd)
    # # Find file descriptors that are already opened (by the shell)
    # Only focus on stdout+stderr for now
    for my $fdno (1..2) {
     	my $fh;
     	# 2-argument-open is used to be compatible with old perl 5.8.0
     	# bug #43570: Perl 5.8.0 creates 61 files
     	if(open($fh,">&=$fdno")) {
     	    $Global::fd{$fdno}=$fh;
     	}
    }
    open $Global::original_stderr, ">&", "STDERR" or
	::die_bug("Can't dup STDERR: $!");
    open $Global::status_fd, ">&", "STDERR" or
	::die_bug("Can't dup STDERR: $!");
    open $Global::original_stdin, "<&", "STDIN" or
	::die_bug("Can't dup STDIN: $!");
}

sub enough_file_handles {
    # Check that we have enough filehandles available for starting
    # another job
    # Uses:
    #   $opt::ungroup
    #   %Global::fd
    # Returns:
    #   1 if ungrouped (thus not needing extra filehandles)
    #   0 if too few filehandles
    #   1 if enough filehandles
    if(not $opt::ungroup) {
        my %fh;
        my $enough_filehandles = 1;
  	# perl uses 7 filehandles for something?
        # open3 uses 2 extra filehandles temporarily
        # We need a filehandle for each redirected file descriptor
	# (normally just STDOUT and STDERR)
	for my $i (1..(7+2+keys %Global::fd)) {
            $enough_filehandles &&= open($fh{$i}, "<", "/dev/null");
        }
        for (values %fh) { close $_; }
        return $enough_filehandles;
    } else {
	# Ungrouped does not need extra file handles
	return 1;
    }
}

sub open_or_exit {
    # Open a file name or exit if the file cannot be opened
    # Inputs:
    #   $file = filehandle or filename to open
    # Uses:
    #   $Global::original_stdin
    # Returns:
    #   $fh = file handle to read-opened file
    my $file = shift;
    if($file eq "-") {
	return ($Global::original_stdin || *STDIN);
    }
    if(ref $file eq "GLOB") {
	# This is an open filehandle
	return $file;
    }
    my $fh = gensym;
    if(not open($fh, "<", $file)) {
        ::error("Cannot open input file `$file': No such file or directory.");
        wait_and_exit(255);
    }
    return $fh;
}

sub set_fh_blocking {
    # Set filehandle as blocking
    # Inputs:
    #   $fh = filehandle to be blocking
    # Returns:
    #   N/A
    my $fh = shift;
    $Global::use{"Fcntl"} ||= eval "use Fcntl qw(:DEFAULT :flock); 1;";
    my $flags;
    # Get the current flags on the filehandle
    fcntl($fh, &F_GETFL, $flags) || die $!;
    # Remove non-blocking from the flags
    $flags &= ~&O_NONBLOCK;
    # Set the flags on the filehandle
    fcntl($fh, &F_SETFL, $flags) || die $!;
}

sub set_fh_non_blocking {
    # Set filehandle as non-blocking
    # Inputs:
    #   $fh = filehandle to be blocking
    # Returns:
    #   N/A
    my $fh = shift;
    $Global::use{"Fcntl"} ||= eval "use Fcntl qw(:DEFAULT :flock); 1;";
    my $flags;
    # Get the current flags on the filehandle
    fcntl($fh, &F_GETFL, $flags) || die $!;
    # Add non-blocking to the flags
    $flags |= &O_NONBLOCK;
    # Set the flags on the filehandle
    fcntl($fh, &F_SETFL, $flags) || die $!;
}


sub __RUNNING_THE_JOBS_AND_PRINTING_PROGRESS__ {}


# Variable structure:
#
#    $Global::running{$pid} = Pointer to Job-object
#    @Global::virgin_jobs = Pointer to Job-object that have received no input
#    $Global::host{$sshlogin} = Pointer to SSHLogin-object
#    $Global::total_running = total number of running jobs
#    $Global::total_started = total jobs started
#    $Global::tty_taken = is the tty in use by a running job?
#    $Global::max_procs_file = filename if --jobs is given a filename
#    $Global::JobQueue = JobQueue object for the queue of jobs
#    $Global::timeoutq = queue of times where jobs timeout
#    $Global::newest_job = Job object of the most recent job started
#    $Global::newest_starttime = timestamp of $Global::newest_job
#    @Global::sshlogin
#    $Global::minimal_command_line_length = minimum length supported by all sshlogins
#    $Global::start_no_new_jobs = should more jobs be started?
#    $Global::original_stderr = file handle for STDERR when the program started
#    $Global::total_started = total number of jobs started
#    $Global::joblog = filehandle of joblog
#    $Global::debug = Is debugging on?
#    $Global::exitstatus = status code of GNU Parallel
#    $Global::quoting = quote the command to run

sub init_run_jobs {
    # Set Global variables and progress signal handlers
    # Do the copying of basefiles
    # Returns: N/A
    $Global::total_running = 0;
    $Global::total_started = 0;
    $Global::tty_taken = 0;
    $SIG{USR1} = \&list_running_jobs;
    $SIG{USR2} = \&toggle_progress;
    if(@opt::basefile) { setup_basefile(); }
}

{
    my $last_time;
    my %last_mtime;
    my $max_procs_file_last_mod;

    sub changed_procs_file {
	# If --jobs is a file and it is modfied:
	# Force recomputing of max_jobs_running for each $sshlogin
	# Uses:
	#   $Global::max_procs_file
	#   %Global::host
	# Returns: N/A
	if($Global::max_procs_file) {
	    # --jobs filename
	    my $mtime = (stat($Global::max_procs_file))[9];
	    $max_procs_file_last_mod ||= 0;
	    if($mtime > $max_procs_file_last_mod) {
		# file changed: Force re-computing max_jobs_running
		$max_procs_file_last_mod = $mtime;
		for my $sshlogin (values %Global::host) {
		    $sshlogin->set_max_jobs_running(undef);
		}
	    }
	}
    }

    sub changed_sshloginfile {
	# If --slf is changed:
	#   reload --slf
	#   filter_hosts
	#   setup_basefile
	# Uses:
	#   @opt::sshloginfile
	#   @Global::sshlogin
	#   %Global::host
	#   $opt::filter_hosts
	# Returns: N/A
	if(@opt::sshloginfile) {
	    # Is --sshloginfile changed?
	    for my $slf (@opt::sshloginfile) {
		my $actual_file = expand_slf_shorthand($slf);
		my $mtime = (stat($actual_file))[9];
		$last_mtime{$actual_file} ||= $mtime;
		if($mtime - $last_mtime{$actual_file} > 1) {
		    ::debug("run","--sshloginfile $actual_file changed. reload\n");
		    $last_mtime{$actual_file} = $mtime;
		    # Reload $slf
		    # Empty sshlogins
		    @Global::sshlogin = ();
		    for (values %Global::host) {
			# Don't start new jobs on any host
			# except the ones added back later
			$_->set_max_jobs_running(0);
		    }
		    # This will set max_jobs_running on the SSHlogins
		    read_sshloginfile($actual_file);
		    parse_sshlogin();
		    $opt::filter_hosts and filter_hosts();
		    setup_basefile();
		}
	    }
	}
    }

    sub start_more_jobs {
	# Run start_another_job() but only if:
	#   * not $Global::start_no_new_jobs set
	#   * not JobQueue is empty
	#   * not load on server is too high
	#   * not server swapping
	#   * not too short time since last remote login
	# Uses:
	#   %Global::host
	#   $Global::start_no_new_jobs
	#   $Global::JobQueue
	#   $opt::pipe
	#   $opt::load
	#   $opt::noswap
	#   $opt::delay
	#   $Global::newest_starttime
	# Returns:
	#   $jobs_started = number of jobs started
	my $jobs_started = 0;
	my $jobs_started_this_round = 0;
	if($Global::start_no_new_jobs) {
	    return $jobs_started;
	}
	if(time - ($last_time||0) > 1) {
	    # At most do this every second
	    $last_time = time;
	    changed_procs_file();
	    changed_sshloginfile();
	}
	do {
	    $jobs_started_this_round = 0;
	    # This will start 1 job on each --sshlogin (if possible)
	    # thus distribute the jobs on the --sshlogins round robin
	    for my $sshlogin (values %Global::host) {
		if($Global::JobQueue->empty() and not $opt::pipe) {
		    # No more jobs in the queue
		    last;
		}
		debug("run", "Running jobs before on ", $sshlogin->string(), ": ",
		      $sshlogin->jobs_running(), "\n");
		if ($sshlogin->jobs_running() < $sshlogin->max_jobs_running()) {
		    if($opt::delay
		       and
		       $opt::delay > ::now() - $Global::newest_starttime) {
			# It has been too short since last start
			next;
		    }
		    if($opt::load and $sshlogin->loadavg_too_high()) {
			# The load is too high or unknown
			next;
		    }
		    if($opt::noswap and $sshlogin->swapping()) {
			# The server is swapping
			next;
		    }
		    if($opt::limit and $sshlogin->limit()) {
			# Over limit
			next;
		    }
		    if($opt::memfree and $sshlogin->memfree() < $opt::memfree) {
			# The server has not enough mem free
			::debug("mem", "Not starting job: not enough mem\n");
			next;
		    }
		    if($sshlogin->too_fast_remote_login()) {
			# It has been too short since
			next;
		    }
		    debug("run", $sshlogin->string(),
			  " has ", $sshlogin->jobs_running(),
			  " out of ", $sshlogin->max_jobs_running(),
			  " jobs running. Start another.\n");
		    if(start_another_job($sshlogin) == 0) {
			# No more jobs to start on this $sshlogin
			debug("run","No jobs started on ",
			      $sshlogin->string(), "\n");
			next;
		    }
		    $sshlogin->inc_jobs_running();
		    $sshlogin->set_last_login_at(::now());
		    $jobs_started++;
		    $jobs_started_this_round++;
		}
		debug("run","Running jobs after on ", $sshlogin->string(), ": ",
		      $sshlogin->jobs_running(), " of ",
		      $sshlogin->max_jobs_running(), "\n");
	    }
	} while($jobs_started_this_round);

	return $jobs_started;
    }
}

{
    my $no_more_file_handles_warned;

    sub start_another_job {
	# If there are enough filehandles
	#   and JobQueue not empty
	#   and not $job is in joblog
	# Then grab a job from Global::JobQueue,
	#   start it at sshlogin
	#   mark it as virgin_job
	# Inputs:
	#   $sshlogin = the SSHLogin to start the job on
	# Uses:
	#   $Global::JobQueue
	#   $opt::pipe
	#   $opt::results
	#   $opt::resume
	#   @Global::virgin_jobs
	# Returns:
	#   1 if another jobs was started
	#   0 otherwise
	my $sshlogin = shift;
	# Do we have enough file handles to start another job?
	if(enough_file_handles()) {
	    if($Global::JobQueue->empty() and not $opt::pipe) {
		# No more commands to run
		debug("start", "Not starting: JobQueue empty\n");
		return 0;
	    } else {
		my $job;
		# Skip jobs already in job log
		# Skip jobs already in results
		do {
		    $job = get_job_with_sshlogin($sshlogin);
		    if(not defined $job) {
			# No command available for that sshlogin
			debug("start", "Not starting: no jobs available for ",
			      $sshlogin->string(), "\n");
			return 0;
		    }
		    if($job->is_already_in_joblog()) {
			$job->free_slot();
		    }
		} while ($job->is_already_in_joblog()
			 or
			 ($opt::results and $opt::resume and $job->is_already_in_results()));
		debug("start", "Command to run on '", $job->sshlogin()->string(), "': '",
		      $job->replaced(),"'\n");
		if($job->start()) {
		    if($opt::pipe) {
			if($job->virgin()) {
			    push(@Global::virgin_jobs,$job);
			} else {
			    # Block already set: This is a retry
			    if(fork()) {
				::debug("pipe","\n\nWriting ",length ${$job->block_ref()},
					" to ", $job->seq(),"\n");
				close $job->fh(0,"w");
			    } else {
				$job->write($job->block_ref());
				close $job->fh(0,"w");
				exit(0);
			    }
			}
		    }
		    debug("start", "Started as seq ", $job->seq(),
			  " pid:", $job->pid(), "\n");
		    return 1;
		} else {
		    # Not enough processes to run the job.
		    # Put it back on the queue.
		    $Global::JobQueue->unget($job);
		    # Count down the number of jobs to run for this SSHLogin.
		    my $max = $sshlogin->max_jobs_running();
		    if($max > 1) { $max--; } else {
			my @arg;
			for my $record (@{$job->{'commandline'}->{'arg_list'}}) {
			    push @arg, map { $_->orig() } @$record;
			}
			::error("No more processes: cannot run a single job. Something is wrong at @arg.");
			::wait_and_exit(255);
		    }
		    $sshlogin->set_max_jobs_running($max);
		    # Sleep up to 300 ms to give other processes time to die
		    ::usleep(rand()*300);
		    ::warning("No more processes: ".
			      "Decreasing number of running jobs to $max.",
			      "Raising ulimit -u or /etc/security/limits.conf may help.");
		    return 0;
		}
	    }
	} else {
	    # No more file handles
	    $no_more_file_handles_warned++ or
		::warning("No more file handles. ",
			  "Raising ulimit -n or /etc/security/limits.conf may help.");
	    return 0;
	}
    }
}

sub init_progress {
    # Uses:
    #   $opt::bar
    # Returns:
    #   list of computers for progress output
    $|=1;
    if($opt::bar) {
	return("","");
    }
    my %progress = progress();
    return ("\nComputers / CPU cores / Max jobs to run\n",
            $progress{'workerlist'});
}

sub drain_job_queue {
    # Uses:
    #   $opt::progress
    #   $Global::total_running
    #   $Global::max_jobs_running
    #   %Global::running
    #   $Global::JobQueue
    #   %Global::host
    #   $Global::start_no_new_jobs
    # Returns: N/A
    if($opt::progress) {
        ::status_no_nl(init_progress());
    }
    my $last_header = "";
    my $sleep = 0.2;
    do {
        while($Global::total_running > 0) {
            debug($Global::total_running, "==", scalar
		  keys %Global::running," slots: ", $Global::max_jobs_running);
	    if($opt::pipe) {
		# When using --pipe sometimes file handles are not closed properly
		for my $job (values %Global::running) {
		    close $job->fh(0,"w");
		}
	    }
            if($opt::progress) {
                my %progress = progress();
                if($last_header ne $progress{'header'}) {
                    ::status("", $progress{'header'});
                    $last_header = $progress{'header'};
                }
                ::status_no_nl("\r",$progress{'status'});
            }
	    if($Global::total_running < $Global::max_jobs_running
	       and not $Global::JobQueue->empty()) {
		# These jobs may not be started because of loadavg
		# or too little time between each ssh login.
		if(start_more_jobs() > 0) {
		    # Exponential back-on if jobs were started
		    $sleep = $sleep/2+0.001;
		}
	    }
            # Exponential back-off sleeping
	    $sleep = ::reap_usleep($sleep);
        }
        if(not $Global::JobQueue->empty()) {
	    # These jobs may not be started:
	    # * because there the --filter-hosts has removed all
	    if(not %Global::host) {
		::error("There are no hosts left to run on.");
		::wait_and_exit(255);
	    }
	    # * because of loadavg
	    # * because of too little time between each ssh login.
            start_more_jobs();
	    $sleep = ::reap_usleep($sleep);
	    if($Global::max_jobs_running == 0) {
		::warning("There are no job slots available. Increase --jobs.");
	    }
        }
	while($opt::sqlmaster and not $Global::sql->finished()) {
	    # SQL master
	    $sleep = ::reap_usleep($sleep);
	    if($Global::start_sqlworker) {
		# Start an SQL worker as we are now sure there is work to do
		$Global::start_sqlworker = 0;
		if(fork()) {
		    # skip
		} else {
		    # Replace --sql/--sqlandworker with --sqlworker
		    my @ARGV = map { s/^--sql(andworker)?$/--sqlworker/; $_ } @Global::options_in_argv;
		    # exec the --sqlworker
		    exec($0,::shell_quote(@ARGV),@command);
		}
	    }
	}
    } while ($Global::total_running > 0
	     or
	     not $Global::start_no_new_jobs and not $Global::JobQueue->empty()
	     or
	     $opt::sqlmaster and not $Global::sql->finished());
    if($opt::progress) {
	my %progress = progress();
	::status("\r".$progress{'status'});
    }
}

sub toggle_progress {
    # Turn on/off progress view
    # Uses:
    #   $opt::progress
    # Returns: N/A
    $opt::progress = not $opt::progress;
    if($opt::progress) {
        ::status_no_nl(init_progress());
    }
}

sub progress {
    # Uses:
    #   $opt::bar
    #   $opt::eta
    #   %Global::host
    #   $Global::total_started
    # Returns:
    #   $workerlist = list of workers
    #   $header = that will fit on the screen
    #   $status = message that will fit on the screen
    if($opt::bar) {
	return ("workerlist" => "", "header" => "", "status" => bar());
    }
    my $eta = "";
    my ($status,$header)=("","");
    if($opt::eta) {
	my($total, $completed, $left, $pctcomplete, $avgtime, $this_eta) =
	    compute_eta();
	$eta = sprintf("ETA: %ds Left: %d AVG: %.2fs  ",
		       $this_eta, $left, $avgtime);
    }
    my $termcols = terminal_columns();
    my @workers = sort keys %Global::host;
    my %sshlogin = map { $_ eq ":" ? ($_ => "local") : ($_ => $_) } @workers;
    my $workerno = 1;
    my %workerno = map { ($_=>$workerno++) } @workers;
    my $workerlist = "";
    for my $w (@workers) {
        $workerlist .=
        $workerno{$w}.":".$sshlogin{$w} ." / ".
            ($Global::host{$w}->ncpus() || "-")." / ".
            $Global::host{$w}->max_jobs_running()."\n";
    }
    $status = "x"x($termcols+1);
    # Select an output format that will fit on a single line
    if(length $status > $termcols) {
        # sshlogin1:XX/XX/XX%/XX.Xs sshlogin2:XX/XX/XX%/XX.Xs sshlogin3:XX/XX/XX%/XX.Xs
        $header = "Computer:jobs running/jobs completed/%of started jobs/Average seconds to complete";
        $status = $eta .
            join(" ",map
                 {
                     if($Global::total_started) {
                         my $completed = ($Global::host{$_}->jobs_completed()||0);
                         my $running = $Global::host{$_}->jobs_running();
                         my $time = $completed ? (time-$^T)/($completed) : "0";
                         sprintf("%s:%d/%d/%d%%/%.1fs ",
                                 $sshlogin{$_}, $running, $completed,
                                 ($running+$completed)*100
                                 / $Global::total_started, $time);
                     }
                 } @workers);
    }
    if(length $status > $termcols) {
        # 1:XX/XX/XX%/XX.Xs 2:XX/XX/XX%/XX.Xs 3:XX/XX/XX%/XX.Xs 4:XX/XX/XX%/XX.Xs
        $header = "Computer:jobs running/jobs completed/%of started jobs";
        $status = $eta .
            join(" ",map
                 {
                     if($Global::total_started) {
			 my $completed = ($Global::host{$_}->jobs_completed()||0);
			 my $running = $Global::host{$_}->jobs_running();
			 my $time = $completed ? (time-$^T)/($completed) : "0";
			 sprintf("%s:%d/%d/%d%%/%.1fs ",
				 $workerno{$_}, $running, $completed,
				 ($running+$completed)*100
				 / $Global::total_started, $time);
		     }
                 } @workers);
    }
    if(length $status > $termcols) {
        # sshlogin1:XX/XX/XX% sshlogin2:XX/XX/XX% sshlogin3:XX/XX/XX%
        $header = "Computer:jobs running/jobs completed/%of started jobs";
        $status = $eta .
            join(" ",map
                 {
                     if($Global::total_started) {
			 sprintf("%s:%d/%d/%d%%",
				 $sshlogin{$_},
				 $Global::host{$_}->jobs_running(),
				 ($Global::host{$_}->jobs_completed()||0),
				 ($Global::host{$_}->jobs_running()+
				  ($Global::host{$_}->jobs_completed()||0))*100
				 / $Global::total_started)
		     }
		 }
                 @workers);
    }
    if(length $status > $termcols) {
        # 1:XX/XX/XX% 2:XX/XX/XX% 3:XX/XX/XX% 4:XX/XX/XX% 5:XX/XX/XX% 6:XX/XX/XX%
        $header = "Computer:jobs running/jobs completed/%of started jobs";
        $status = $eta .
            join(" ",map
                 {
                     if($Global::total_started) {
			 sprintf("%s:%d/%d/%d%%",
				 $workerno{$_},
				 $Global::host{$_}->jobs_running(),
				 ($Global::host{$_}->jobs_completed()||0),
				 ($Global::host{$_}->jobs_running()+
				  ($Global::host{$_}->jobs_completed()||0))*100
				 / $Global::total_started)
		     }
		 }
                 @workers);
    }
    if(length $status > $termcols) {
        # sshlogin1:XX/XX/XX% sshlogin2:XX/XX/XX% sshlogin3:XX/XX sshlogin4:XX/XX
        $header = "Computer:jobs running/jobs completed";
        $status = $eta .
            join(" ",map
                       { sprintf("%s:%d/%d",
                                 $sshlogin{$_}, $Global::host{$_}->jobs_running(),
                                 ($Global::host{$_}->jobs_completed()||0)) }
                       @workers);
    }
    if(length $status > $termcols) {
        # sshlogin1:XX/XX sshlogin2:XX/XX sshlogin3:XX/XX sshlogin4:XX/XX
        $header = "Computer:jobs running/jobs completed";
        $status = $eta .
            join(" ",map
                       { sprintf("%s:%d/%d",
                                 $sshlogin{$_}, $Global::host{$_}->jobs_running(),
                                 ($Global::host{$_}->jobs_completed()||0)) }
                       @workers);
    }
    if(length $status > $termcols) {
        # 1:XX/XX 2:XX/XX 3:XX/XX 4:XX/XX 5:XX/XX 6:XX/XX
        $header = "Computer:jobs running/jobs completed";
        $status = $eta .
            join(" ",map
                       { sprintf("%s:%d/%d",
                                 $workerno{$_}, $Global::host{$_}->jobs_running(),
                                 ($Global::host{$_}->jobs_completed()||0)) }
                       @workers);
    }
    if(length $status > $termcols) {
        # sshlogin1:XX sshlogin2:XX sshlogin3:XX sshlogin4:XX sshlogin5:XX
        $header = "Computer:jobs completed";
        $status = $eta .
            join(" ",map
                       { sprintf("%s:%d",
                                 $sshlogin{$_},
                                 ($Global::host{$_}->jobs_completed()||0)) }
                       @workers);
    }
    if(length $status > $termcols) {
        # 1:XX 2:XX 3:XX 4:XX 5:XX 6:XX
        $header = "Computer:jobs completed";
        $status = $eta .
            join(" ",map
                       { sprintf("%s:%d",
                                 $workerno{$_},
                                 ($Global::host{$_}->jobs_completed()||0)) }
                       @workers);
    }
    return ("workerlist" => $workerlist, "header" => $header, "status" => $status);
}

{

    my ($total, $first_completed, $smoothed_avg_time, $last_eta);

    sub compute_eta {
	# Calculate important numbers for ETA
	# Returns:
	#   $total = number of jobs in total
	#   $completed = number of jobs completed
	#   $left = number of jobs left
	#   $pctcomplete = percent of jobs completed
	#   $avgtime = averaged time
	#   $eta = smoothed eta
	$total = $Global::JobQueue->total_jobs();
	my $completed = $Global::total_completed;
	my $left = $total - $completed;
	if(not $completed) {
	    return($total, $completed, $left, 0, 0, 0);
	}
	my $pctcomplete = $completed / $total;
	$first_completed ||= time;
	my $timepassed = (time - $first_completed);
	my $avgtime = $timepassed / $completed;
	$smoothed_avg_time ||= $avgtime;
	# Smooth the eta so it does not jump wildly
	$smoothed_avg_time = (1 - $pctcomplete) * $smoothed_avg_time +
	    $pctcomplete * $avgtime;
	my $eta = int($left * $smoothed_avg_time);
	if($eta*0.90 < $last_eta and $last_eta < $eta) {
	    # Eta jumped less that 10% up: Keep the last eta instead
	    $eta = $last_eta;
	} else {
	    $last_eta = $eta;
	}
	return($total, $completed, $left, $pctcomplete, $avgtime, $eta);
    }
}

{
    my ($rev,$reset);

    sub bar {
	# Return:
	#   $status = bar with eta, completed jobs, arg and pct
	$rev ||= "\033[7m";
	$reset ||= "\033[0m";
	my($total, $completed, $left, $pctcomplete, $avgtime, $eta) =
	    compute_eta();
	my $arg = $Global::newest_job ?
	    $Global::newest_job->{'commandline'}->
	    replace_placeholders(["\257<\257>"],0,0) : "";
	# These chars mess up display in the terminal
	$arg =~ tr/[\011-\016\033\302-\365]//d;
	my $bar_text =
	    sprintf("%d%% %d:%d=%ds %s",
		    $pctcomplete*100, $completed, $left, $eta, $arg);
	my $terminal_width = terminal_columns();
	my $s = sprintf("%-${terminal_width}s",
			substr($bar_text." "x$terminal_width,
			       0,$terminal_width));
	my $width = int($terminal_width * $pctcomplete);
	substr($s,$width,0) = $reset;
	my $zenity = sprintf("%-${terminal_width}s",
			     substr("#   $eta sec $arg",
				    0,$terminal_width));
	$s = "\r" . $zenity . "\r" . $pctcomplete*100 . # Prefix with zenity header
	    "\r" . $rev . $s . $reset;
	return $s;
    }
}

{
    my ($columns,$last_column_time);

    sub terminal_columns {
	# Get the number of columns of the terminal.
        # Only update once per second.
	# Returns:
	#   number of columns of the screen
	if(not $columns or $last_column_time < time) {
	    $last_column_time = time;
	    $columns = $ENV{'COLUMNS'};
	    if(not $columns) {
		my $stty = ::qqx("stty -a </dev/tty");
		# FreeBSD/OpenBSD/NetBSD/Dragonfly/MirOS
		# MacOSX/IRIX/AIX/Tru64
		$stty =~ /(\d+) columns/ and do { $columns = $1; };
		# GNU/Linux/Solaris
		$stty =~ /columns (\d+)/ and do { $columns = $1; };
		# Solaris-x86/HPUX/SCOsysV/UnixWare/OpenIndiana
		$stty =~ /columns = (\d+)/ and do { $columns = $1; };
		# QNX
		$stty =~ /rows=\d+,(\d+)/ and do { $columns = $1; };
	    }
	    if(not $columns) {
		my $resize = ::qqx("resize");
		$resize =~ /COLUMNS=(\d+);/ and do { $columns = $1; };
	    }
	    $columns ||= 80;
	}
	return $columns;
    }
}

sub get_job_with_sshlogin {
    # Input:
    #   $sshlogin = which host should the job be run on?
    # Uses:
    #   $opt::hostgroups
    #   $Global::JobQueue
    # Returns:
    #   $job = next job object for $sshlogin if any available
    my $sshlogin = shift;
    my $job;

    if ($opt::hostgroups) {
	my @other_hostgroup_jobs = ();

        while($job = $Global::JobQueue->get()) {
	    if($sshlogin->in_hostgroups($job->hostgroups())) {
		# Found a job to be run on a hostgroup of this
		# $sshlogin
		last;
	    } else {
		# This job was not in the hostgroups of $sshlogin
                push @other_hostgroup_jobs, $job;
            }
        }
	$Global::JobQueue->unget(@other_hostgroup_jobs);
	if(not defined $job) {
	    # No more jobs
	    return undef;
	}
    } else {
        $job = $Global::JobQueue->get();
        if(not defined $job) {
            # No more jobs
	    ::debug("start", "No more jobs: JobQueue empty\n");
            return undef;
        }
    }

    my $clean_command = $job->replaced();
    if($clean_command =~ /^\s*$/) {
        # Do not run empty lines
        if(not $Global::JobQueue->empty()) {
            return get_job_with_sshlogin($sshlogin);
        } else {
            return undef;
        }
    }
    $job->set_sshlogin($sshlogin);
    if($opt::retries and $clean_command and
       $job->failed_here()) {
        # This command with these args failed for this sshlogin
        my ($no_of_failed_sshlogins,$min_failures) = $job->min_failed();
	# Only look at the Global::host that have > 0 jobslots
        if($no_of_failed_sshlogins ==
	   grep { $_->max_jobs_running() > 0 } values %Global::host
	   and $job->failed_here() == $min_failures) {
            # It failed the same or more times on another host:
            # run it on this host
        } else {
            # If it failed fewer times on another host:
            # Find another job to run
            my $nextjob;
            if(not $Global::JobQueue->empty()) {
		# This can potentially recurse for all args
                no warnings 'recursion';
                $nextjob = get_job_with_sshlogin($sshlogin);
            }
            # Push the command back on the queue
            $Global::JobQueue->unget($job);
            return $nextjob;
        }
    }
    return $job;
}


sub __REMOTE_SSH__ {}


sub read_sshloginfiles {
    # Read a list of --slf's
    # Input:
    #   @files = files or symbolic file names to read
    # Returns: N/A
    for my $s (@_) {
	read_sshloginfile(expand_slf_shorthand($s));
    }
}

sub expand_slf_shorthand {
    # Expand --slf shorthand into a read file name
    # Input:
    #   $file = file or symbolic file name to read
    # Returns:
    #   $file = actual file name to read
    my $file = shift;
    if($file eq "-") {
	# skip: It is stdin
    } elsif($file eq "..") {
        $file = $Global::config_dir."/sshloginfile";
    } elsif($file eq ".") {
        $file = "/etc/parallel/sshloginfile";
    } elsif(not -r $file) {
	for(@Global::config_dirs) {
	    if(not -r $_."/".$file) {
		# Try prepending $PARALLEL_HOME
		::error("Cannot open $file.");
		::wait_and_exit(255);
	    } else {
		$file = $_."/".$file;
		last;
	    }
	}
    }
    return $file;
}

sub read_sshloginfile {
    # Read sshloginfile into @Global::sshlogin
    # Input:
    #   $file = file to read
    # Uses:
    #   @Global::sshlogin
    # Returns: N/A
    local $/ = "\n";
    my $file = shift;
    my $close = 1;
    my $in_fh;
    ::debug("init","--slf ",$file);
    if($file eq "-") {
	$in_fh = *STDIN;
	$close = 0;
    } else {
	if(not open($in_fh, "<", $file)) {
	    # Try the filename
	    ::error("Cannot open $file.");
	    ::wait_and_exit(255);
	}
    }
    while(<$in_fh>) {
        chomp;
        /^\s*#/ and next;
        /^\s*$/ and next;
        push @Global::sshlogin, $_;
    }
    if($close) {
	close $in_fh;
    }
}

sub parse_sshlogin {
    # Parse @Global::sshlogin into %Global::host.
    # Keep only hosts that are in one of the given ssh hostgroups.
    # Uses:
    #   @Global::sshlogin
    #   $Global::minimal_command_line_length
    #   %Global::host
    #   $opt::transfer
    #   @opt::return
    #   $opt::cleanup
    #   @opt::basefile
    #   @opt::trc
    # Returns: N/A
    my @login;
    if(not @Global::sshlogin) { @Global::sshlogin = (":"); }
    for my $sshlogin (@Global::sshlogin) {
        # Split up -S sshlogin,sshlogin
        for my $s (split /,|\n/, $sshlogin) {
            if ($s eq ".." or $s eq "-") {
		# This may add to @Global::sshlogin - possibly bug
		read_sshloginfile(expand_slf_shorthand($s));
            } else {
		$s =~ s/\s*$//;
                push (@login, $s);
            }
        }
    }
    $Global::minimal_command_line_length = 8_000_000;
    my @allowed_hostgroups;
    for my $ncpu_sshlogin_string (::uniq(@login)) {
	my $sshlogin = SSHLogin->new($ncpu_sshlogin_string);
	my $sshlogin_string = $sshlogin->string();
	if($sshlogin_string eq "") {
	    # This is an ssh group: -S @webservers
	    push @allowed_hostgroups, $sshlogin->hostgroups();
	    next;
	}
	if($Global::host{$sshlogin_string}) {
	    # This sshlogin has already been added:
	    # It is probably a host that has come back
	    # Set the max_jobs_running back to the original
	    debug("run","Already seen $sshlogin_string\n");
	    if($sshlogin->{'ncpus'}) {
		# If ncpus set by '#/' of the sshlogin, overwrite it:
		$Global::host{$sshlogin_string}->set_ncpus($sshlogin->ncpus());
	    }
	    $Global::host{$sshlogin_string}->set_max_jobs_running(undef);
	    next;
	}
	$sshlogin->set_maxlength(Limits::Command::max_length());

	$Global::minimal_command_line_length =
	    ::min($Global::minimal_command_line_length, $sshlogin->maxlength());
        $Global::host{$sshlogin_string} = $sshlogin;
    }
    if(@allowed_hostgroups) {
	# Remove hosts that are not in these groups
	while (my ($string, $sshlogin) = each %Global::host) {
	    if(not $sshlogin->in_hostgroups(@allowed_hostgroups)) {
		delete $Global::host{$string};
	    }
	}
    }

    # debug("start", "sshlogin: ", my_dump(%Global::host),"\n");
    if(@Global::transfer_files or @opt::return or $opt::cleanup or @opt::basefile) {
        if(not remote_hosts()) {
            # There are no remote hosts
            if(@opt::trc) {
		::warning("--trc ignored as there are no remote --sshlogin.");
            } elsif (defined $opt::transfer) {
		::warning("--transfer ignored as there are no remote --sshlogin.");
            } elsif (@opt::transfer_files) {
		::warning("--transferfile ignored as there are no remote --sshlogin.");
            } elsif (@opt::return) {
                ::warning("--return ignored as there are no remote --sshlogin.");
            } elsif (defined $opt::cleanup) {
		::warning("--cleanup ignored as there are no remote --sshlogin.");
            } elsif (@opt::basefile) {
                ::warning("--basefile ignored as there are no remote --sshlogin.");
            }
        }
    }
}

sub remote_hosts {
    # Return sshlogins that are not ':'
    # Uses:
    #   %Global::host
    # Returns:
    #   list of sshlogins with ':' removed
    return grep !/^:$/, keys %Global::host;
}

sub setup_basefile {
    # Transfer basefiles to each $sshlogin
    # This needs to be done before first jobs on $sshlogin is run
    # Uses:
    #   %Global::host
    #   @opt::basefile
    # Returns: N/A
    my @cmd;
    my $rsync_destdir;
    my $workdir;
    for my $sshlogin (values %Global::host) {
      if($sshlogin->string() eq ":") { next }
      for my $file (@opt::basefile) {
	if($file !~ m:^/: and $opt::workdir eq "...") {
	  ::error("Work dir '...' will not work with relative basefiles.");
	  ::wait_and_exit(255);
	}
	if(not $workdir) {
	    my $dummycmdline = CommandLine->new(1,["true"],{},0,0,[],[],{},{},{});
	    my $dummyjob = Job->new($dummycmdline);
	    $workdir = $dummyjob->workdir();
	}
	push @cmd, $sshlogin->rsync_transfer_cmd($file,$workdir);
      }
    }
    debug("init", "basesetup: @cmd\n");
    my ($exitstatus,$stdout_ref,$stderr_ref) =
	run_parallel((join "\n",@cmd),"-j0","--retries",5);
    if($exitstatus) {
	my @stdout = @$stdout_ref;
	my @stderr = @$stderr_ref;
	::error("Copying of --basefile failed: @stdout@stderr");
	::wait_and_exit(255);
    }
}

sub cleanup_basefile {
    # Remove the basefiles transferred
    # Uses:
    #   %Global::host
    #   @opt::basefile
    # Returns: N/A
    my @cmd;
    my $workdir;
    if(not $workdir) {
	my $dummycmdline = CommandLine->new(1,"true",0,0,0,0,0,{},{},{});
	my $dummyjob = Job->new($dummycmdline);
	$workdir = $dummyjob->workdir();
    }
    for my $sshlogin (values %Global::host) {
        if($sshlogin->string() eq ":") { next }
        for my $file (@opt::basefile) {
	    push @cmd, $sshlogin->cleanup_cmd($file,$workdir);
        }
    }
    debug("init", "basecleanup: @cmd\n");
    my ($exitstatus,$stdout_ref,$stderr_ref) =
	run_parallel(join("\n",@cmd),"-j0","--retries",5);
    if($exitstatus) {
	my @stdout = @$stdout_ref;
	my @stderr = @$stderr_ref;
	::error("Cleanup of --basefile failed: @stdout@stderr");
	::wait_and_exit(255);
    }
}

sub run_parallel {
    my ($stdin,@args) = @_;
    my $cmd = join "",map { " $_ & " } split /\n/, $stdin;
    print $Global::original_stderr ` $cmd wait` ;
    return 0
}

sub _run_parallel {
    # Run GNU Parallel
    # This should ideally just fork an internal copy
    # and not start it through a shell
    # Input:
    #   $stdin = data to provide on stdin for GNU Parallel
    #   @args = command line arguments
    # Returns:
    #   $exitstatus = exitcode of GNU Parallel run
    #   \@stdout = standard output
    #   \@stderr = standard error
    my ($stdin,@args) = @_;
    my ($exitstatus,@stdout,@stderr);
    my ($stdin_fh,$stdout_fh)=(gensym(),gensym());
    my ($stderr_fh, $stderrname) = ::tmpfile(SUFFIX => ".par");
    unlink $stderrname;

    my $pid = ::open3($stdin_fh,$stdout_fh,$stderr_fh,
		      $0,qw(--plain --shell /bin/sh --will-cite), @args);
    if(my $writerpid = fork()) {
	close $stdin_fh;
	@stdout = <$stdout_fh>;
	# Now stdout is closed:
	# These pids should be dead or die very soon
	while(kill 0, $writerpid) { ::usleep(1); }
	die;
#	reap $writerpid;
#	while(kill 0, $pid) { ::usleep(1); }
#	reap $writerpid;
	$exitstatus = $?;
	seek $stderr_fh, 0, 0;
	@stderr = <$stderr_fh>;
	close $stdout_fh;
	close $stderr_fh;
    } else {
	close $stdout_fh;
	close $stderr_fh;
	print $stdin_fh $stdin;
	close $stdin_fh;
	exit(0);
    }
    return ($exitstatus,\@stdout,\@stderr);
}

sub filter_hosts {
    # Remove down --sshlogins from active duty.
    # Find ncpus, ncores, maxlen, time-to-login for each host.
    # Uses:
    #   %Global::host
    #   $Global::minimal_command_line_length
    #   $opt::use_cpus_instead_of_cores
    # Returns: N/A

    my ($ncores_ref, $ncpus_ref, $time_to_login_ref, $maxlen_ref,
	$echo_ref, $down_hosts_ref) =
	    parse_host_filtering(parallelized_host_filtering());

    delete @Global::host{@$down_hosts_ref};
    @$down_hosts_ref and ::warning("Removed @$down_hosts_ref.");

    $Global::minimal_command_line_length = 8_000_000;
    while (my ($sshlogin, $obj) = each %Global::host) {
	if($sshlogin eq ":") { next }
	$ncpus_ref->{$sshlogin} or
	    ::die_bug("ncpus missing: ".$obj->serverlogin());
	$ncores_ref->{$sshlogin} or
	    ::die_bug("ncores missing: ".$obj->serverlogin());
	$time_to_login_ref->{$sshlogin} or
	    ::die_bug("time_to_login missing: ".$obj->serverlogin());
	$maxlen_ref->{$sshlogin} or
	    ::die_bug("maxlen missing: ".$obj->serverlogin());
	if($opt::use_cpus_instead_of_cores) {
	    $obj->set_ncpus($ncpus_ref->{$sshlogin});
	} else {
	    $obj->set_ncpus($ncores_ref->{$sshlogin});
	}
	$obj->set_time_to_login($time_to_login_ref->{$sshlogin});
        $obj->set_maxlength($maxlen_ref->{$sshlogin});
	$Global::minimal_command_line_length =
	    ::min($Global::minimal_command_line_length,
		  int($maxlen_ref->{$sshlogin}/2));
	::debug("init", "Timing from -S:$sshlogin ",
		" ncpus:",$ncpus_ref->{$sshlogin},
		" ncores:", $ncores_ref->{$sshlogin},
		" time_to_login:", $time_to_login_ref->{$sshlogin},
		" maxlen:", $maxlen_ref->{$sshlogin},
		" min_max_len:", $Global::minimal_command_line_length,"\n");
    }
}

sub parse_host_filtering {
    # Input:
    #   @lines = output from parallelized_host_filtering()
    # Returns:
    #   \%ncores = number of cores of {host}
    #   \%ncpus = number of cpus of {host}
    #   \%time_to_login = time_to_login on {host}
    #   \%maxlen = max command len on {host}
    #   \%echo = echo received from {host}
    #   \@down_hosts = list of hosts with no answer
    local $/ = "\n";
    my (%ncores, %ncpus, %time_to_login, %maxlen, %echo, @down_hosts);
    for (@_) {
	::debug("init",$_);
	chomp;
	my @col = split /\t/, $_;
	if(defined $col[6]) {
	    # This is a line from --joblog
	    # seq host time spent sent received exit signal command
	    # 2 : 1372607672.654 0.675 0 0 0 0 eval true\ m\;ssh\ m\ parallel\ --number-of-cores
	    if($col[0] eq "Seq" and $col[1] eq "Host" and
		    $col[2] eq "Starttime") {
		# Header => skip
		next;
	    }
	    # Get server from: eval true server\;
	    $col[8] =~ /eval true..([^;]+).;/ or
		::die_bug("col8 does not contain host: $col[8]");
	    my $host = $1;
	    $host =~ tr/\\//d;
	    $Global::host{$host} or next;
	    if($col[6] eq "255" or $col[6] eq "-1" or $col[6] eq "1") {
		# exit == 255 or exit == timeout (-1): ssh failed/timedout
		# exit == 1: lsh failed
		# Remove sshlogin
		::debug("init", "--filtered $host\n");
		push(@down_hosts, $host);
	    } elsif($col[6] eq "127") {
		# signal == 127: parallel not installed remote
		# Set ncpus and ncores = 1
		::warning("Could not figure out ".
			  "number of cpus on $host. Using 1.");
		$ncores{$host} = 1;
		$ncpus{$host} = 1;
		$maxlen{$host} = Limits::Command::max_length();
	    } elsif($col[0] =~ /^\d+$/ and $Global::host{$host}) {
		# Remember how log it took to log in
		# 2 : 1372607672.654 0.675 0 0 0 0 eval true\ m\;ssh\ m\ echo
		$time_to_login{$host} = ::min($time_to_login{$host},$col[3]);
	    } else {
		::die_bug("host check unmatched long jobline: $_");
	    }
	} elsif($Global::host{$col[0]}) {
	    # This output from --number-of-cores, --number-of-cpus,
	    # --max-line-length-allowed
	    # ncores: server       8
	    # ncpus:  server       2
	    # maxlen: server       131071
	    if(/parallel: Warning: Cannot figure out number of/) {
		next;
	    }
	    if(not $ncores{$col[0]}) {
		$ncores{$col[0]} = $col[1];
	    } elsif(not $ncpus{$col[0]}) {
		$ncpus{$col[0]} = $col[1];
	    } elsif(not $maxlen{$col[0]}) {
		$maxlen{$col[0]} = $col[1];
	    } elsif(not $echo{$col[0]}) {
		$echo{$col[0]} = $col[1];
	    } elsif(m/perl: warning:|LANGUAGE =|LC_ALL =|LANG =|are supported and installed/) {
		# Skip these:
		# perl: warning: Setting locale failed.
		# perl: warning: Please check that your locale settings:
		#         LANGUAGE = (unset),
		#         LC_ALL = (unset),
		#         LANG = "en_US.UTF-8"
		#     are supported and installed on your system.
		# perl: warning: Falling back to the standard locale ("C").
	    } else {
		::die_bug("host check too many col0: $_");
	    }
	} else {
	    ::die_bug("host check unmatched short jobline ($col[0]): $_");
	}
    }
    @down_hosts = uniq(@down_hosts);
    return(\%ncores, \%ncpus, \%time_to_login, \%maxlen, \%echo, \@down_hosts);
}

sub parallelized_host_filtering {
    # Uses:
    #   %Global::host
    # Returns:
    #   text entries with:
    #   * joblog line
    #   * hostname \t number of cores
    #   * hostname \t number of cpus
    #   * hostname \t max-line-length-allowed
    #   * hostname \t empty

    sub sshwrapped {
	# Wrap with ssh and --env
	my $sshlogin = shift;
	my $command = shift;
	my $commandline = CommandLine->new(1,[$command],{},0,0,[],[],{},{},{});
	my $job = Job->new($commandline);
	$job->set_sshlogin($sshlogin);
	$job->wrapped();
	return($job->{'wrapped'});
    }

    my(@cores, @cpus, @maxline, @echo);
    while (my ($host, $sshlogin) = each %Global::host) {
	if($host eq ":") { next }
	# The 'true' is used to get the $host out later
	push(@cores, $host."\t"."true $host; ".
	     sshwrapped($sshlogin,"parallel --number-of-cores")."\n\0");
	push(@cpus, $host."\t"."true $host; ".
	     sshwrapped($sshlogin,"parallel --number-of-cpus")."\n\0");
	push(@maxline, $host."\t"."true $host; ".
	     sshwrapped($sshlogin,"parallel --max-line-length-allowed")."\n\0");
	# 'echo' is used to get the fastest possible ssh login time
	my $sshcmd = "true $host; exec " .$sshlogin->sshcommand()." ".
	    $sshlogin->serverlogin();
	push(@echo, $host."\t".$sshcmd." -- echo\n\0");
    }

    # --timeout 10: Setting up an SSH connection and running a simple
    #               command should never take > 10 sec.
    # --delay 0.1:  If multiple sshlogins use the same proxy the delay
    #               will make it less likely to overload the ssh daemon.
    # --retries 3:  If the ssh daemon is overloaded, try 3 times
    my $cmd =
	"$0 -j0 --timeout 10 --joblog - --plain --delay 0.1 --retries 3 ".
	"--tag --tagstring '{1}' -0 --colsep '\t' -k eval '{2}' && true ";
    $cmd = $Global::shell." -c ".::shell_quote_scalar($cmd);
    ::debug("init", $cmd, "\n");
    my @out;
    my $prepend = "";

    my ($host_fh,$in,$err);
    open3($in, $host_fh, $err, $cmd) || ::die_bug("parallel host check: $cmd");
    if(not fork()) {
	# Give the commands to run to the $cmd
	close $host_fh;
	print $in @cores, @cpus, @maxline, @echo;
	close $in;
	exit();
    }
    close $in;
    for(<$host_fh>) {
	if(/\'$/) {
	    # if last char = ' then append next line
	    # This may be due to quoting of \n in environment var
	    $prepend .= $_;
	    next;
	}
	$_ = $prepend . $_;
	$prepend = "";
	push @out, $_;
    }
    close $host_fh;
    return @out;
}

sub onall {
    # Runs @command on all hosts.
    # Uses parallel to run @command on each host.
    # --jobs = number of hosts to run on simultaneously.
    # For each host a parallel command with the args will be running.
    # Uses:
    #   $Global::quoting
    #   @opt::basefile
    #   $opt::jobs
    #   $opt::linebuffer
    #   $opt::ungroup
    #   $opt::group
    #   $opt::keeporder
    #   $opt::D
    #   $opt::plain
    #   $opt::max_chars
    #   $opt::linebuffer
    #   $opt::files
    #   $opt::colsep
    #   $opt::timeout
    #   $opt::plain
    #   $opt::retries
    #   $opt::max_chars
    #   $opt::arg_sep
    #   $opt::arg_file_sep
    #   @opt::v
    #   @opt::env
    #   %Global::host
    #   $Global::exitstatus
    #   $Global::debug
    #   $Global::joblog
    #   $opt::joblog
    #   $opt::tag
    #   $opt::tee
    # Input:
    #   @command = command to run on all hosts
    # Returns: N/A
    sub tmp_joblog {
	# Input:
	#   $joblog = filename of joblog - undef if none
	# Returns:
	#   $tmpfile = temp file for joblog - undef if none
	my $joblog = shift;
	if(not defined $joblog) {
	    return undef;
	}
	my ($fh, $tmpfile) = ::tmpfile(SUFFIX => ".log");
	close $fh;
	return $tmpfile;
    }
    my ($input_source_fh_ref,@command) = @_;
    if($Global::quoting) {
       @command = shell_quote(@command);
    }

    # Copy all @input_source_fh (-a and :::) into tempfiles
    my @argfiles = ();
    for my $fh (@$input_source_fh_ref) {
	my ($outfh, $name) = ::tmpfile(SUFFIX => ".all", UNLINK => not $opt::D);
	print $outfh (<$fh>);
	close $outfh;
	push @argfiles, $name;
    }
    if(@opt::basefile) { setup_basefile(); }
    # for each sshlogin do:
    # parallel -S $sshlogin $command :::: @argfiles
    #
    # Pass some of the options to the sub-parallels, not all of them as
    # -P should only go to the first, and -S should not be copied at all.
    my $options =
	join(" ",
	     ((defined $opt::D) ? "-D $opt::D" : ""),
	     ((defined $opt::group) ? "-g" : ""),
	     ((defined $opt::jobs) ? "-P $opt::jobs" : ""),
	     ((defined $opt::keeporder) ? "--keeporder" : ""),
	     ((defined $opt::linebuffer) ? "--linebuffer" : ""),
	     ((defined $opt::max_chars) ? "--max-chars ".$opt::max_chars : ""),
	     ((defined $opt::plain) ? "--plain" : ""),
	     ((defined $opt::ungroup) ? "-u" : ""),
	     ((defined $opt::tee) ? "--tee" : ""),
	);
    my $suboptions =
	join(" ",
	     ((defined $opt::D) ? "-D $opt::D" : ""),
	     ((defined $opt::arg_file_sep) ? "--arg-file-sep ".$opt::arg_file_sep : ""),
	     ((defined $opt::arg_sep) ? "--arg-sep ".$opt::arg_sep : ""),
	     ((defined $opt::colsep) ? "--colsep ".shell_quote($opt::colsep) : ""),
	     ((defined $opt::files) ? "--files" : ""),
	     ((defined $opt::group) ? "-g" : ""),
	     ((defined $opt::cleanup) ? "--cleanup" : ""),
	     ((defined $opt::keeporder) ? "--keeporder" : ""),
	     ((defined $opt::linebuffer) ? "--linebuffer" : ""),
	     ((defined $opt::max_chars) ? "--max-chars ".$opt::max_chars : ""),
	     ((defined $opt::plain) ? "--plain" : ""),
	     ((defined $opt::retries) ? "--retries ".$opt::retries : ""),
	     ((defined $opt::timeout) ? "--timeout ".$opt::timeout : ""),
	     ((defined $opt::ungroup) ? "-u" : ""),
	     ((defined $opt::tee) ? "--tee" : ""),
	     ((defined $opt::workdir) ? "--wd ".::shell_quote_scalar($opt::workdir) : ""),
	     (@Global::transfer_files ? map { "--tf ".::shell_quote_scalar($_) }
	      @Global::transfer_files : ""),
	     (@Global::ret_files ? map { "--return ".::shell_quote_scalar($_) }
	      @Global::ret_files : ""),
	     (@opt::env ? map { "--env ".::shell_quote_scalar($_) } @opt::env : ""),
	     (map { "-v" } @opt::v),
	);
    ::debug("init", "| $0 $options\n");
    open(my $parallel_fh, "|-", "$0 --will-cite -j0 $options") ||
	::die_bug("This does not run GNU Parallel: $0 $options");
    my @joblogs;
    for my $host (sort keys %Global::host) {
	my $sshlogin = $Global::host{$host};
	my $joblog = tmp_joblog($opt::joblog);
	if($joblog) {
	    push @joblogs, $joblog;
	    $joblog = "--joblog $joblog";
	}
	my $quad = $opt::arg_file_sep || "::::";
	::debug("init", "$0 $suboptions -j1 $joblog ",
	    ((defined $opt::tag) ?
	     "--tagstring ".shell_quote_scalar($sshlogin->string()) : ""),
	     " -S ", shell_quote_scalar($sshlogin->string())," ",
	     join(" ",shell_quote(@command))," $quad @argfiles\n");
	print $parallel_fh "$0 $suboptions -j1 $joblog ",
	    ((defined $opt::tag) ?
	     "--tagstring ".shell_quote_scalar($sshlogin->string()) : ""),
	     " -S ", shell_quote_scalar($sshlogin->string())," ",
	     join(" ",shell_quote(@command))," $quad @argfiles\n";
    }
    close $parallel_fh;
    $Global::exitstatus = $? >> 8;
    debug("init", "--onall exitvalue ", $?);
    if(@opt::basefile and $opt::cleanup) { cleanup_basefile(); }
    $Global::debug or unlink(@argfiles);
    my %seen;
    for my $joblog (@joblogs) {
	# Append to $joblog
	open(my $fh, "<", $joblog) || ::die_bug("Cannot open tmp joblog $joblog");
	# Skip first line (header);
	<$fh>;
	print $Global::joblog (<$fh>);
	close $fh;
	unlink($joblog);
    }
}


sub __SIGNAL_HANDLING__ {}


sub sigtstp {
    # Send TSTP signal (Ctrl-Z) to all children process groups
    # Uses:
    #   %SIG
    # Returns: N/A
    signal_children("TSTP");
}

sub sigpipe {
    # Send SIGPIPE signal to all children process groups
    # Uses:
    #   %SIG
    # Returns: N/A
    signal_children("PIPE");
}

sub signal_children {
    # Send signal to all children process groups
    # and GNU Parallel itself
    # Uses:
    #   %SIG
    # Returns: N/A
    my $signal = shift;
    debug("run", "Sending $signal ");
    kill $signal, map { -$_ } keys %Global::running;
    # Use default signal handler for GNU Parallel itself
    $SIG{$signal} = undef;
    kill $signal, $$;
}

sub save_original_signal_handler {
    # Remember the original signal handler
    # Uses:
    #   %Global::original_sig
    # Returns: N/A
    $SIG{INT} = sub {
	if($opt::tmux) { ::qqx("tmux kill-session -t p$$"); }
	wait_and_exit(255);
    };
    $SIG{TERM} = sub {
	if($opt::tmux) { ::qqx("tmux kill-session -t p$$"); }
	wait_and_exit(255);
    };
    %Global::original_sig = %SIG;
    $SIG{TERM} = sub {}; # Dummy until jobs really start
    $SIG{ALRM} = 'IGNORE';
    # Allow Ctrl-Z to suspend and `fg` to continue
    $SIG{TSTP} = \&sigtstp;
    $SIG{PIPE} = \&sigpipe;
    $SIG{CONT} = sub {
	# Set $SIG{TSTP} again (it is undef'ed in sigtstp() )
	$SIG{TSTP} = \&sigtstp;
	# Send continue signal to all children process groups
	kill "CONT", map { -$_ } keys %Global::running;
    };
}

sub list_running_jobs {
    # Print running jobs on tty
    # Uses:
    #   %Global::running
    # Returns: N/A
    for my $job (values %Global::running) {
        ::status("$Global::progname: ".$job->replaced());
    }
}

sub start_no_new_jobs {
    # Start no more jobs
    # Uses:
    #    %Global::original_sig
    #    %Global::unlink
    #    $Global::start_no_new_jobs
    # Returns: N/A
    $SIG{TERM} = $Global::original_sig{TERM};
    unlink keys %Global::unlink;
    ::status
        ("$Global::progname: SIGTERM received. No new jobs will be started.",
         "$Global::progname: Waiting for these ".(keys %Global::running).
         " jobs to finish. Send SIGTERM again to stop now.");
    list_running_jobs();
    $Global::start_no_new_jobs ||= 1;
}

sub reaper {
    # A job finished.
    # Print the output.
    # Start another job
    # Uses:
    #   %Global::sshmaster
    #   %Global::running
    #   $Global::tty_taken
    #   $opt::timeout
    #   $Global::timeoutq
    #   $opt::halt
    #   $opt::keeporder
    #   $Global::total_running
    # Returns:
    #   @pids_reaped = PIDs of children finished
    my $stiff;
    my @pids_reaped;
    my $children_reaped = 0;
    debug("run", "Reaper ");
    # For efficiency surround with BEGIN/COMMIT when using $opt::sqlmaster
    $opt::sqlmaster and $Global::sql->run("BEGIN;");
    while (($stiff = waitpid(-1, &WNOHANG)) > 0) {
	# $stiff = pid of dead process
	if(wantarray) {
	    push(@pids_reaped,$stiff);
	} else {
	    $children_reaped++;
	}
        if($Global::sshmaster{$stiff}) {
            # This is one of the ssh -M: ignore
            next;
        }
        my $job = $Global::running{$stiff};

	# '-a <(seq 10)' will give us a pid not in %Global::running
        $job or next;
        delete $Global::running{$stiff};
        $Global::total_running--;
	if($job->{'commandline'}{'skip'}) {
	    # $job->skip() was called
	    $job->set_exitstatus(-2);
	    $job->set_exitsignal(0);
	} else {
	    $job->set_exitstatus($? >> 8);
	    $job->set_exitsignal($? & 127);
	}

        debug("run", "seq ",$job->seq()," died (", $job->exitstatus(), ")");
        $job->set_endtime(::now());
        if($stiff == $Global::tty_taken) {
            # The process that died had the tty => release it
            $Global::tty_taken = 0;
        }
        my $sshlogin = $job->sshlogin();
        $sshlogin->dec_jobs_running();
        if(not $job->should_be_retried()) {
	    # The job is done
	    $sshlogin->inc_jobs_completed();
	    # Free the jobslot
	    $job->free_slot();
	    if($opt::timeout and not $job->exitstatus()) {
		# Update average runtime for timeout only for successful jobs
		$Global::timeoutq->update_median_runtime($job->runtime());
	    }
	    if($opt::keeporder) {
		$job->print_earlier_jobs();
	    } else {
		$job->print();
	    }
	    if($job->should_we_halt() eq "now") {
		# Kill children
		::kill_sleep_seq($job->pid());
		::killall();
		::wait_and_exit($Global::halt_exitstatus);
            }
        }
	$job->cleanup();
	start_more_jobs();
	if($opt::progress) {
	    my %progress = progress();
	    ::status_no_nl("\r",$progress{'status'});
	}
    }
    $opt::sqlmaster and $Global::sql->run("COMMIT;");
    debug("run", "done ");
    return wantarray ? @pids_reaped : $children_reaped;
}


sub __USAGE__ {}


sub killall {
    # Kill all jobs by killing their process groups

    $Global::start_no_new_jobs ||= 1;
    $Global::killall ||= 1;
    kill_sleep_seq(keys %Global::running);
}

sub kill_sleep_seq {
    # Send jobs TERM,TERM,KILL to processgroups
    # Input:
    #   @pids = list of pids that are also processgroups
    # Convert pids to process groups ($processgroup = -$pid)
    my @pgrps = map { -$_ } @_;
    my @term_seq = split/,/,$opt::termseq;
    if(not @term_seq) {
	@term_seq = ("TERM",200,"TERM",100,"TERM",50,"KILL",25);
    }
    while(@term_seq) {
	@pgrps = kill_sleep(shift @term_seq, shift @term_seq, @pgrps);
    }
}

sub kill_sleep {
    my ($signal, $sleep_max, @pids) = @_;
    ::debug("kill","kill_sleep $signal ",(join " ",sort @pids),"\n");
    kill $signal, @pids;
    my $sleepsum = 0;
    my $sleep = 0.001;
    my @dead;

    while(@pids and $sleepsum < $sleep_max) {
	if($Global::killall) {
	    # Killall => don't run reaper
	    my $stiff;
	    while (($stiff = waitpid(-1, &WNOHANG)) > 0) {
		# remove $stiff from @pids
		@pids = grep { $_ != $stiff } @pids;
		$sleep = $sleep/2+0.001;
	    }
	} elsif(@dead = reaper()) {
	    # Remove reaped pids
	    for my $stiff (@dead) {
                @pids = grep { $_ != $stiff } @pids;
	    }
	    $sleep = $sleep/2+0.001;
	}
	@pids = grep { kill( 0, $_) } @pids;
	$sleep *= 1.1;
	::usleep($sleep);
	$sleepsum += $sleep;
	# Remove dead children
	@pids = grep { kill( 0, $_) } @pids;
    }
    return @pids;
}

sub wait_and_exit {
    # If we do not wait, we sometimes get segfault
    # Returns: N/A
    my $error = shift;
    unlink keys %Global::unlink;
    if($error) {
	# Kill all jobs without printing
	killall();
    }
    for (keys %Global::unkilled_children) {
	# Kill any (non-jobs) children
        kill 9, $_;
        waitpid($_,0);
        delete $Global::unkilled_children{$_};
    }
    wait();
    exit($error);
}

sub die_usage {
    # Returns: N/A
    usage();
    wait_and_exit(255);
}

sub usage {
    # Returns: N/A
    print join
	("\n",
	 "Usage:",
	 "",
	 "$Global::progname [options] [command [arguments]] < list_of_arguments",
	 "$Global::progname [options] [command [arguments]] (::: arguments|:::: argfile(s))...",
	 "cat ... | $Global::progname --pipe [options] [command [arguments]]",
	 "",
	 "-j n            Run n jobs in parallel",
	 "-k              Keep same order",
	 "-X              Multiple arguments with context replace",
	 "--colsep regexp Split input on regexp for positional replacements",
	 "{} {.} {/} {/.} {#} {%} {= perl code =} Replacement strings",
	 "{3} {3.} {3/} {3/.} {=3 perl code =}    Positional replacement strings",
	 "With --plus:    {} = {+/}/{/} = {.}.{+.} = {+/}/{/.}.{+.} = {..}.{+..} =",
	 "                {+/}/{/..}.{+..} = {...}.{+...} = {+/}/{/...}.{+...}",
	 "",
	 "-S sshlogin     Example: foo\@server.example.com",
	 "--slf ..        Use ~/.parallel/sshloginfile as the list of sshlogins",
	 "--trc {}.bar    Shorthand for --transfer --return {}.bar --cleanup",
	 "--onall         Run the given command with argument on all sshlogins",
	 "--nonall        Run the given command with no arguments on all sshlogins",
	 "",
	 "--pipe          Split stdin (standard input) to multiple jobs.",
	 "--recend str    Record end separator for --pipe.",
	 "--recstart str  Record start separator for --pipe.",
	 "",
	 "See 'man $Global::progname' for details",
	 "",
	 "Academic tradition requires you to cite works you base your article on.",
	 "If you use programs that use GNU Parallel to process data for an article in a",
	 "scientific publication, please cite:",
	 "",
	 "  O. Tange (2011): GNU Parallel - The Command-Line Power Tool,",
	 "  ;login: The USENIX Magazine, February 2011:42-47.",
	 "",
	 "This helps funding further development; AND IT WON'T COST YOU A CENT.",
	 "If you pay 10000 EUR you should feel free to use GNU Parallel without citing.",
	 "",
	 "",);
}

sub citation_notice {
    # if --will-cite or --plain: do nothing
    # if stderr redirected: do nothing
    # if $PARALLEL_HOME/will-cite: do nothing
    # else: print citation notice to stderr
    if($opt::willcite
       or
       $opt::plain
       or
       not -t $Global::original_stderr
       or
       grep { -e "$_/will-cite" } @Global::config_dirs) {
	# skip
    } else {
	::status
	    ("Academic tradition requires you to cite works you base your article on.",
	     "If you use programs that use GNU Parallel to process data for an article in a",
	     "scientific publication, please cite:",
	     "",
	     "  O. Tange (2011): GNU Parallel - The Command-Line Power Tool,",
	     "  ;login: The USENIX Magazine, February 2011:42-47.",
	     "",
	     "This helps funding further development; AND IT WON'T COST YOU A CENT.",
	     "If you pay 10000 EUR you should feel free to use GNU Parallel without citing.",
	     "",
	     "To silence this citation notice: run 'parallel --citation'.",
	     ""
	    );
    }
}

sub status {
    my @w = @_;
    my $fh = $Global::status_fd || *STDERR;
    print $fh map { ($_, "\n") } @w;
    flush $fh;
}

sub status_no_nl {
    my @w = @_;
    my $fh = $Global::status_fd || *STDERR;
    print $fh @w;
    flush $fh;
}

sub warning {
    my @w = @_;
    my $prog = $Global::progname || "parallel";
    status_no_nl(map { ($prog, ": Warning: ", $_, "\n"); } @w);
}

sub error {
    my @w = @_;
    my $prog = $Global::progname || "parallel";
    status(map { ($prog.": Error: ". $_); } @w);
}

sub die_bug {
    my $bugid = shift;
    print STDERR
	("$Global::progname: This should not happen. You have found a bug.\n",
	 "Please contact <parallel\@gnu.org> and follow\n",
	 "https://www.gnu.org/software/parallel/man.html#REPORTING-BUGS\n",
	 "\n",
	 "Include this in the report:\n",
	 "* The version number: $Global::version\n",
	 "* The bugid: $bugid\n",
	 "* The command line being run\n",
	 "* The files being read (put the files on a webserver if they are big)\n",
	 "\n",
	 "If you get the error on smaller/fewer files, please include those instead.\n");
    ::wait_and_exit(255);
}

sub version {
    # Returns: N/A
    print join("\n",
               "GNU $Global::progname $Global::version",
               "Copyright (C) 2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017",
	       "Ole Tange and Free Software Foundation, Inc.",
               "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>",
               "This is free software: you are free to change and redistribute it.",
               "GNU $Global::progname comes with no warranty.",
               "",
               "Web site: http://www.gnu.org/software/${Global::progname}\n",
	       "When using programs that use GNU Parallel to process data for publication",
	       "please cite as described in 'parallel --citation'.\n",
        );
}

sub citation {
    # Returns: N/A
    ::status(
	  "Academic tradition requires you to cite works you base your article on.",
	  "If you use programs that use GNU Parallel to process data for an article in a",
	  "scientific publication, please cite:",
	  "",
	  "\@article{Tange2011a,",
	  "  title = {GNU Parallel - The Command-Line Power Tool},",
	  "  author = {O. Tange},",
	  "  address = {Frederiksberg, Denmark},",
	  "  journal = {;login: The USENIX Magazine},",
	  "  month = {Feb},",
	  "  number = {1},",
	  "  volume = {36},",
	  "  url = {http://www.gnu.org/s/parallel},",
	  "  year = {2011},",
	  "  pages = {42-47},",
	  "  doi = {http://dx.doi.org/10.5281/zenodo.16303}",
	  "}",
	  "",
	  "(Feel free to use \\nocite{Tange2011a})",
	  "",
	  "This helps funding further development; AND IT WON'T COST YOU A CENT.",
	  "If you pay 10000 EUR you should feel free to use GNU Parallel without citing.",
	  "",
	  "If you send a copy of your published article to tange\@gnu.org, it will be",
	  "mentioned in the release notes of next version of GNU Parallel.",
	  ""
        );
    while(not grep { -e "$_/will-cite" } @Global::config_dirs) {
	print "\nType: 'will cite' and press enter.\n> ";
	my $input = <STDIN>;
	if(not defined $input) {
	    exit(255);
	}
	if($input =~ /will cite/i) {
	    mkdir $Global::config_dir;
	    if(open (my $fh, ">", $Global::config_dir."/will-cite")) {
		close $fh;
		::status(
		    "",
		    "Thank you for your support. It is much appreciated. The citation",
		    "notice is now silenced.",
		    "");
	    } else {
		::status(
		      "",
		      "Thank you for your support. It is much appreciated. The citation",
		      "cannot permanently be silenced. Use '--will-cite' instead.",
		      "",
		      "If you use '--will-cite' in scripts to be run by others you are making",
		      "it harder for others to see the citation notice.  The development of",
		      "GNU parallel is indirectly financed through citations, so if users",
		      "do not know they should cite then you are making it harder to finance",
		      "development. However, if you pay 10000 EUR, you should feel free to",
		      "use '--will-cite' in scripts.",
		      "");
		last;
	    }
	}
    }
}

sub show_limits {
    # Returns: N/A
    print("Maximal size of command: ",Limits::Command::real_max_length(),"\n",
          "Maximal used size of command: ",Limits::Command::max_length(),"\n",
          "\n",
          "Execution of  will continue now, and it will try to read its input\n",
          "and run commands; if this is not what you wanted to happen, please\n",
          "press CTRL-D or CTRL-C\n");
}


sub __GENERIC_COMMON_FUNCTION__ {}


sub mkdir_or_die {
    # If dir is not executable: die
    my $dir = shift;
    # The eval is needed to catch exception from mkdir
    eval { File::Path::mkpath($dir); };
    if(not -x $dir) {
	::error("Cannot change into non-executable dir $dir: $!");
	::wait_and_exit(255);
    }
}

sub tmpfile {
    # Create tempfile as $TMPDIR/parXXXXX
    # Returns:
    #   $filehandle = opened file handle
    #   $filename = file name created
    my($filehandle,$filename) =
	::tempfile(DIR=>$ENV{'TMPDIR'}, TEMPLATE => 'parXXXXX', @_);
    if(wantarray) {
	return($filehandle,$filename);
    } else {
	# Separate unlink due to NFS dealing badly with File::Temp
	unlink $filename;
	return $filehandle;
    }
}

sub tmpname {
    # Select a name that does not exist
    # Do not create the file as it may be used for creating a socket (by tmux)
    # Remember the name in $Global::unlink to avoid hitting the same name twice
    my $name = shift;
    my($tmpname);
    if(not -w $ENV{'TMPDIR'}) {
	if(not -e $ENV{'TMPDIR'}) {
	    ::error("Tmpdir '$ENV{'TMPDIR'}' does not exist.","Try 'mkdir $ENV{'TMPDIR'}'");
	} else {
	    ::error("Tmpdir '$ENV{'TMPDIR'}' is not writable.","Try 'chmod +w $ENV{'TMPDIR'}'");
	}
	::wait_and_exit(255);
    }
    do {
	$tmpname = $ENV{'TMPDIR'}."/".$name.
	    join"", map { (0..9,"a".."z","A".."Z")[rand(62)] } (1..5);
    } while(-e $tmpname or $Global::unlink{$tmpname}++);
    return $tmpname;
}

sub tmpfifo {
    # Find an unused name and mkfifo on it
    use POSIX qw(mkfifo);
    my $tmpfifo = tmpname("fif",@_);
    mkfifo($tmpfifo,0600);
    return $tmpfifo;
}

sub rm {
    # Remove file and remove it from %Global::unlink
    # Uses:
    #   %Global::unlink
    delete @Global::unlink{@_};
    unlink @_;
}

sub size_of_block_dev {
    # Like -s but for block devices
    # Input:
    #   $blockdev = file name of block device
    # Returns:
    #   $size = in bytes, undef if error
    my $blockdev = shift;
    if(open(my $fh, "<", $blockdev)) {
	seek($fh,0,2) || ::die_bug("cannot seek $blockdev");
	my $size = tell($fh);
	close $fh;
	return $size;
    } else {
	::error("cannot open $blockdev");
	wait_and_exit(255);
    }
}

sub qqx {
    # Like qx but with clean environment (except for @keep)
    # and STDERR ignored
    # This is needed if the environment contains functions
    # that /bin/sh does not understand
    my $PATH = $ENV{'PATH'};
    my %env;
    # ssh with ssh-agent needs PATH SSH_AUTH_SOCK SSH_AGENT_PID
    # ssh with Kerberos needs KRB5CCNAME
    # tmux needs LC_CTYPE
    my @keep = qw(PATH SSH_AUTH_SOCK SSH_AGENT_PID KRB5CCNAME LC_CTYPE);
    @env{@keep} = @ENV{@keep};
    local %ENV;
    %ENV = %env;
    if($Global::debug) {
	return qx{ @_ && true };
    } else {
	return qx{ ( @_ ) 2>/dev/null };
    }
}

sub uniq {
    # Remove duplicates and return unique values
    return keys %{{ map { $_ => 1 } @_ }};
}

sub min {
    # Returns:
    #   Minimum value of array
    my $min;
    for (@_) {
        # Skip undefs
        defined $_ or next;
        defined $min or do { $min = $_; next; }; # Set $_ to the first non-undef
        $min = ($min < $_) ? $min : $_;
    }
    return $min;
}

sub max {
    # Returns:
    #   Maximum value of array
    my $max;
    for (@_) {
        # Skip undefs
        defined $_ or next;
        defined $max or do { $max = $_; next; }; # Set $_ to the first non-undef
        $max = ($max > $_) ? $max : $_;
    }
    return $max;
}

sub sum {
    # Returns:
    #   Sum of values of array
    my @args = @_;
    my $sum = 0;
    for (@args) {
        # Skip undefs
        $_ and do { $sum += $_; }
    }
    return $sum;
}

sub undef_as_zero {
    my $a = shift;
    return $a ? $a : 0;
}

sub undef_as_empty {
    my $a = shift;
    return $a ? $a : "";
}

sub undef_if_empty {
    if(defined($_[0]) and $_[0] eq "") {
	return undef;
    }
    return $_[0];
}

sub multiply_binary_prefix {
    # Evalualte numbers with binary prefix
    # Ki=2^10, Mi=2^20, Gi=2^30, Ti=2^40, Pi=2^50, Ei=2^70, Zi=2^80, Yi=2^80
    # ki=2^10, mi=2^20, gi=2^30, ti=2^40, pi=2^50, ei=2^70, zi=2^80, yi=2^80
    # K =2^10, M =2^20, G =2^30, T =2^40, P =2^50, E =2^70, Z =2^80, Y =2^80
    # k =10^3, m =10^6, g =10^9, t=10^12, p=10^15, e=10^18, z=10^21, y=10^24
    # 13G = 13*1024*1024*1024 = 13958643712
    # Input:
    #   $s = string with prefixes
    # Returns:
    #   $value = int with prefixes multiplied
    my @v = @_;
    for(@v) {
	defined $_ or next;
	s/ki/*1024/gi;
	s/mi/*1024*1024/gi;
	s/gi/*1024*1024*1024/gi;
	s/ti/*1024*1024*1024*1024/gi;
	s/pi/*1024*1024*1024*1024*1024/gi;
	s/ei/*1024*1024*1024*1024*1024*1024/gi;
	s/zi/*1024*1024*1024*1024*1024*1024*1024/gi;
	s/yi/*1024*1024*1024*1024*1024*1024*1024*1024/gi;
	s/xi/*1024*1024*1024*1024*1024*1024*1024*1024*1024/gi;

	s/K/*1024/g;
	s/M/*1024*1024/g;
	s/G/*1024*1024*1024/g;
	s/T/*1024*1024*1024*1024/g;
	s/P/*1024*1024*1024*1024*1024/g;
	s/E/*1024*1024*1024*1024*1024*1024/g;
	s/Z/*1024*1024*1024*1024*1024*1024*1024/g;
	s/Y/*1024*1024*1024*1024*1024*1024*1024*1024/g;
	s/X/*1024*1024*1024*1024*1024*1024*1024*1024*1024/g;

	s/k/*1000/g;
	s/m/*1000*1000/g;
	s/g/*1000*1000*1000/g;
	s/t/*1000*1000*1000*1000/g;
	s/p/*1000*1000*1000*1000*1000/g;
	s/e/*1000*1000*1000*1000*1000*1000/g;
	s/z/*1000*1000*1000*1000*1000*1000*1000/g;
	s/y/*1000*1000*1000*1000*1000*1000*1000*1000/g;
	s/x/*1000*1000*1000*1000*1000*1000*1000*1000*1000/g;

	$_ = eval $_;
    }
    return wantarray ? @v : $v[0];
}

{
    my ($disk_full_fh, $b8193, $error_printed);
    sub exit_if_disk_full {
	# Checks if $TMPDIR is full by writing 8kb to a tmpfile
	# If the disk is full: Exit immediately.
	# Returns:
	#   N/A
	if(not $disk_full_fh) {
	    $disk_full_fh = ::tmpfile(SUFFIX => ".df");
	    $b8193 = "x"x8193;
	}
	# Linux does not discover if a disk is full if writing <= 8192
	# Tested on:
	# bfs btrfs cramfs ext2 ext3 ext4 ext4dev jffs2 jfs minix msdos
	# ntfs reiserfs tmpfs ubifs vfat xfs
	# TODO this should be tested on different OS similar to this:
	#
	# doit() {
	#   sudo mount /dev/ram0 /mnt/loop; sudo chmod 1777 /mnt/loop
	#   seq 100000 | parallel --tmpdir /mnt/loop/ true &
	#   seq 6900000 > /mnt/loop/i && echo seq OK
	#   seq 6980868 > /mnt/loop/i
	#   seq 10000 > /mnt/loop/ii
	#   sleep 3
	#   sudo umount /mnt/loop/ || sudo umount -l /mnt/loop/
	#   echo >&2
	# }
	print $disk_full_fh $b8193;
	if(not $disk_full_fh
	   or
	   tell $disk_full_fh != 8193) {
	    # On raspbian the disk can be full except for 10 chars.
	    if(not $error_printed) {
		::error("Output is incomplete. Cannot append to buffer file in $ENV{'TMPDIR'}. Is the disk full?",
			"Change \$TMPDIR with --tmpdir or use --compress.");
		$error_printed = 1;
	    }
	    ::wait_and_exit(255);
	}
	truncate $disk_full_fh, 0;
	seek($disk_full_fh, 0, 0) || die;
    }
}

sub spacefree {
    # Remove comments and spaces
    # Inputs:
    #   $spaces = keep 1 space?
    #   $s = string to remove spaces from
    # Returns:
    #   $s = with spaces removed
    my $spaces = shift;
    my $s = shift;
    $s =~ s/#.*//mg;
    if($spaces) {
	$s =~ s/\s+/ /mg;
    } else {
	$s =~ s/\s//mg;
    }
    return $s;
}

{
    my $hostname;
    sub hostname {
	local $/ = "\n";
	if(not $hostname) {
	    $hostname = `hostname`;
	    chomp($hostname);
	    $hostname ||= "nohostname";
	}
	return $hostname;
    }
}

sub which {
    # Input:
    #   @programs = programs to find the path to
    # Returns:
    #   @full_path = full paths to @programs. Nothing if not found
    my @which;
    for my $prg (@_) {
	push(@which, grep { not -d $_ and -x $_ }
	     map { $_."/".$prg } split(":",$ENV{'PATH'}));
    }
    return @which;
}

{
    my ($regexp,%fakename);

    sub parent_shell {
	# Input:
	#   $pid = pid to see if (grand)*parent is a shell
	# Returns:
	#   $shellpath = path to shell - undef if no shell found
	my $pid = shift;
	if(not $regexp) {
	    # All shells known to mankind
	    #
	    # ash bash csh dash fdsh fish fizsh ksh ksh93 mksh pdksh
	    # posh rbash rc rush rzsh sash sh static-sh tcsh yash zsh
	    my @shells = (qw(ash bash csh dash fdsh fish fizsh ksh
	    ksh93 lksh mksh pdksh posh rbash rc rush rzsh sash sh
	    static-sh tcsh yash zsh -sh -csh -bash),
			  '-sh (sh)' # sh on FreeBSD
		);
	    # Can be formatted as:
	    #   [sh]  -sh  sh  busybox sh  -sh (sh)
	    #   /bin/sh /sbin/sh /opt/csw/sh
	    # But not: foo.sh sshd crash flush pdflush scosh fsflush ssh
	    my $shell = "(?:".join("|",map { "\Q$_\E" } @shells).")";
	    $regexp = '^((\[)('. $shell. ')(\])|(|\S+/|busybox )('. $shell. '))($| [^(])';
	    %fakename = (
		# sh disguises itself as -sh (sh) on FreeBSD
		"-sh (sh)" => ["sh"],
		# csh and tcsh disguise themselves as -sh/-csh
		"-sh" => ["csh", "tcsh"],
		"-csh" => ["tcsh", "csh"],
		# bash disguises itself as -bash
		"-bash" => ["bash", "sh"],
		);
	}
	my ($children_of_ref, $parent_of_ref, $name_of_ref) = pid_table();
	my $shellpath;
	my $testpid = $pid;
	while($testpid) {
	    ::debug("init", "shell? ". $name_of_ref->{$testpid}."\n");
	    if($name_of_ref->{$testpid} =~ /$regexp/o) {
		::debug("init", "which ".($3||$6)." => ");
		$shellpath = (which($3 || $6,@{$fakename{$3 || $6}}))[0];
		::debug("init", "shell path $shellpath\n");
		$shellpath and last;
	    }
	    if($testpid == $parent_of_ref->{$testpid}) {
		# In Solaris zones, the PPID of the zsched process is itself
		last;
	    }
	    $testpid = $parent_of_ref->{$testpid};
	}
	return $shellpath;
    }
}

{
    my %pid_parentpid_cmd;

    sub pid_table {
	# Returns:
	#   %children_of = { pid -> children of pid }
	#   %parent_of = { pid -> pid of parent }
	#   %name_of = { pid -> commandname }

       	if(not %pid_parentpid_cmd) {
	    # Filter for SysV-style `ps`
	    my $sysv = q( ps -ef | perl -ane '1..1 and /^(.*)CO?MM?A?N?D/ and $s=length $1;).
		q(s/^.{$s}//; print "@F[1,2] $_"' );
	    # Crazy msys: ' is not accepted on the cmd line, but " are treated as '
	    my $msys = q( ps -ef | perl -ane "1..1 and /^(.*)CO?MM?A?N?D/ and $s=length $1;).
		q(s/^.{$s}//; print qq{@F[1,2] $_}" );
	    # BSD-style `ps`
	    my $bsd = q(ps -o pid,ppid,command -ax);
	    %pid_parentpid_cmd =
	    (
	     'aix' => $sysv,
	     'android' => $sysv,
	     'cygwin' => $sysv,
	     'darwin' => $bsd,
	     'dec_osf' => $sysv,
	     'dragonfly' => $bsd,
	     'freebsd' => $bsd,
	     'gnu' => $sysv,
	     'hpux' => $sysv,
	     'linux' => $sysv,
	     'mirbsd' => $bsd,
	     'msys' => $msys,
	     'MSWin32' => $sysv,
	     'netbsd' => $bsd,
	     'nto' => $sysv,
	     'openbsd' => $bsd,
	     'solaris' => $sysv,
	     'svr5' => $sysv,
	     'syllable' => "echo ps not supported",
	    );
	}
	$pid_parentpid_cmd{$^O} or ::die_bug("pid_parentpid_cmd for $^O missing");

	my (@pidtable,%parent_of,%children_of,%name_of);
	# Table with pid -> children of pid
	@pidtable = `$pid_parentpid_cmd{$^O}`;
	my $p=$$;
	for (@pidtable) {
	    # must match: 24436 21224 busybox ash
	    # must match: 24436 21224 <<empty on MacOSX running cubase>>
	    # must match: 24436 21224 <<empty on system running Viber>>
	    #   or: perl -e 'while($0=" "){}'
	    if(/^\s*(\S+)\s+(\S+)\s+(\S+.*)/
	       or
	       /^\s*(\S+)\s+(\S+)\s+()$/) {
		$parent_of{$1} = $2;
		push @{$children_of{$2}}, $1;
		$name_of{$1} = $3;
	    } else {
		::die_bug("pidtable format: $_");
	    }
	}
	return(\%children_of, \%parent_of, \%name_of);
    }
}

sub now {
    # Returns time since epoch as in seconds with 3 decimals
    # Uses:
    #   @Global::use
    # Returns:
    #   $time = time now with millisecond accuracy
    if(not $Global::use{"Time::HiRes"}) {
	if(eval "use Time::HiRes qw ( time );") {
	    eval "sub TimeHiRestime { return Time::HiRes::time };";
	} else {
	    eval "sub TimeHiRestime { return time() };";
	}
	$Global::use{"Time::HiRes"} = 1;
    }

    return (int(TimeHiRestime()*1000))/1000;
}

sub usleep {
    # Sleep this many milliseconds.
    # Input:
    #   $ms = milliseconds to sleep
    my $ms = shift;
    ::debug("timing",int($ms),"ms ");
    select(undef, undef, undef, $ms/1000);
}

sub reap_usleep {
    # Reap dead children.
    # If no dead children: Sleep specified amount with exponential backoff
    # Input:
    #   $ms = milliseconds to sleep
    # Returns:
    #   $ms/2+0.001 if children reaped
    #   $ms*1.1 if no children reaped
    my $ms = shift;
    if(reaper()) {
	if(not $Global::total_completed % 100) {
	    if($opt::timeout) {
		# Force cleaning the timeout queue for every 1000 jobs
		# Fixes potential memleak
		$Global::timeoutq->process_timeouts();
	    }
	}
	# Sleep exponentially shorter (1/2^n) if a job finished
	return $ms/2+0.001;
    } else {
	if($opt::timeout) {
	    $Global::timeoutq->process_timeouts();
	}
	if($opt::memfree) {
	    kill_youngster_if_not_enough_mem();
	}
	if($opt::limit) {
	    kill_youngest_if_over_limit();
	}
	if($ms > 0.002) {
	    # When a child dies, wake up from sleep (or select(,,,))
	    $SIG{CHLD} = sub { kill "ALRM", $$ };
	    usleep($ms);
	    # --compress needs $SIG{CHLD} unset
	    $SIG{CHLD} = 'DEFAULT';
	}
	exit_if_disk_full();
	if($opt::linebuffer) {
	    my $something_printed = 0;
	    if($opt::keeporder) {
		for my $job (values %Global::running) {
		    $something_printed += $job->print_earlier_jobs();
		}
	    } else {
		for my $job (values %Global::running) {
		    $something_printed += $job->print();
		}
	    }
	    if($something_printed) {
		$ms = $ms/2+0.001;
	    }
	}
	# Sleep exponentially longer (1.1^n) if a job did not finish,
	# though at most 1000 ms.
	return (($ms < 1000) ? ($ms * 1.1) : ($ms));
    }
}

sub kill_youngest_if_over_limit {
    # Check each $sshlogin we are over limit
    # If over limit: kill off the youngest child
    # Put the child back in the queue.
    # Uses:
    #   %Global::running
    my %jobs_of;
    my @sshlogins;

    for my $job (values %Global::running) {
	if(not $jobs_of{$job->sshlogin()}) {
	    push @sshlogins, $job->sshlogin();
	}
	push @{$jobs_of{$job->sshlogin()}}, $job;
    }
    for my $sshlogin (@sshlogins) {
	for my $job (sort { $b->seq() <=> $a->seq() } @{$jobs_of{$sshlogin}}) {
	    if($sshlogin->limit() == 2) {
		$job->kill();
		last;
	    }
	}
    }
}

sub kill_youngster_if_not_enough_mem {
    # Check each $sshlogin if there is enough mem.
    # If less than 50% enough free mem: kill off the youngest child
    # Put the child back in the queue.
    # Uses:
    #   %Global::running
    my %jobs_of;
    my @sshlogins;

    for my $job (values %Global::running) {
	if(not $jobs_of{$job->sshlogin()}) {
	    push @sshlogins, $job->sshlogin();
	}
	push @{$jobs_of{$job->sshlogin()}}, $job;
    }
    for my $sshlogin (@sshlogins) {
	for my $job (sort { $b->seq() <=> $a->seq() } @{$jobs_of{$sshlogin}}) {
	    if($sshlogin->memfree() < $opt::memfree * 0.5) {
		::debug("mem","\n",map { $_->seq()." " }
			(sort { $b->seq() <=> $a->seq() }
			 @{$jobs_of{$sshlogin}}));
		::debug("mem","\n", $job->seq(), "killed ",
			$sshlogin->memfree()," < ",$opt::memfree * 0.5);
		$job->kill();
		$sshlogin->memfree_recompute();
	    } else {
		last;
	    }
	}
	::debug("mem","Free mem OK ",
		$sshlogin->memfree()," > ",$opt::memfree * 0.5);
    }
}


sub __DEBUGGING__ {}


sub debug {
    # Uses:
    #   $Global::debug
    #   %Global::fd
    # Returns: N/A
    $Global::debug or return;
    @_ = grep { defined $_ ? $_ : "" } @_;
    if($Global::debug eq "all" or $Global::debug eq $_[0]) {
	if($Global::fd{1}) {
	    # Original stdout was saved
	    my $stdout = $Global::fd{1};
	    print $stdout @_[1..$#_];
	} else {
	    print @_[1..$#_];
	}
    }
}

sub my_memory_usage {
    # Returns:
    #   memory usage if found
    #   0 otherwise
    use strict;
    use FileHandle;

    local $/ = "\n";
    my $pid = $$;
    if(-e "/proc/$pid/stat") {
        my $fh = FileHandle->new("</proc/$pid/stat");

        my $data = <$fh>;
        chomp $data;
        $fh->close;

        my @procinfo = split(/\s+/,$data);

        return undef_as_zero($procinfo[22]);
    } else {
        return 0;
    }
}

sub my_size {
    # Returns:
    #   $size = size of object if Devel::Size is installed
    #   -1 otherwise
    my @size_this = (@_);
    eval "use Devel::Size qw(size total_size)";
    if ($@) {
        return -1;
    } else {
        return total_size(@_);
    }
}

sub my_dump {
    # Returns:
    #   ascii expression of object if Data::Dump(er) is installed
    #   error code otherwise
    my @dump_this = (@_);
    eval "use Data::Dump qw(dump);";
    if ($@) {
        # Data::Dump not installed
        eval "use Data::Dumper;";
        if ($@) {
            my $err =  "Neither Data::Dump nor Data::Dumper is installed\n".
                "Not dumping output\n";
            ::status($err);
            return $err;
        } else {
            return Dumper(@dump_this);
        }
    } else {
	# Create a dummy Data::Dump:dump as Hans Schou sometimes has
	# it undefined
	eval "sub Data::Dump:dump {}";
        eval "use Data::Dump qw(dump);";
        return (Data::Dump::dump(@dump_this));
    }
}

sub my_croak {
    eval "use Carp; 1";
    $Carp::Verbose = 1;
    croak(@_);
}

sub my_carp {
    eval "use Carp; 1";
    $Carp::Verbose = 1;
    carp(@_);
}


sub __OBJECT_ORIENTED_PARTS__ {}


package SSHLogin;

sub new {
    my $class = shift;
    my $sshlogin_string = shift;
    my $ncpus;
    my %hostgroups;
    # SSHLogins can have these formats:
    #   @grp+grp/ncpu//usr/bin/ssh user@server
    #   ncpu//usr/bin/ssh user@server
    #   /usr/bin/ssh user@server
    #   user@server
    #   ncpu/user@server
    #   @grp+grp/user@server
    if($sshlogin_string =~ s:^\@([^/]+)/?::) {
        # Look for SSHLogin hostgroups
        %hostgroups = map { $_ => 1 } split(/\+/, $1);
    }
    if ($sshlogin_string =~ s:^(\d+)/::) {
        # Override default autodetected ncpus unless missing
        $ncpus = $1;
    }
    my $string = $sshlogin_string;
    # An SSHLogin is always in the hostgroup of its $string-name
    $hostgroups{$string} = 1;
    @Global::hostgroups{keys %hostgroups} = values %hostgroups;
    my @unget = ();
    my $no_slash_string = $string;
    $no_slash_string =~ s/[^-a-z0-9:]/_/gi;
    return bless {
        'string' => $string,
        'jobs_running' => 0,
        'jobs_completed' => 0,
        'maxlength' => undef,
        'max_jobs_running' => undef,
        'orig_max_jobs_running' => undef,
        'ncpus' => $ncpus,
        'hostgroups' => \%hostgroups,
        'sshcommand' => undef,
        'serverlogin' => undef,
        'control_path_dir' => undef,
        'control_path' => undef,
	'time_to_login' => undef,
	'last_login_at' => undef,
        'loadavg_file' => $Global::cache_dir . "/tmp/sshlogin/" .
	    $no_slash_string . "/loadavg",
        'loadavg' => undef,
	'last_loadavg_update' => 0,
        'swap_activity_file' => $Global::cache_dir . "/tmp/sshlogin/" .
            $no_slash_string . "/swap_activity",
        'swap_activity' => undef,
    }, ref($class) || $class;
}

sub DESTROY {
    my $self = shift;
    # Remove temporary files if they are created.
    ::rm($self->{'loadavg_file'});
    ::rm($self->{'swap_activity_file'});
}

sub string {
    my $self = shift;
    return $self->{'string'};
}

sub jobs_running {
    my $self = shift;
    return ($self->{'jobs_running'} || "0");
}

sub inc_jobs_running {
    my $self = shift;
    $self->{'jobs_running'}++;
}

sub dec_jobs_running {
    my $self = shift;
    $self->{'jobs_running'}--;
}

sub set_maxlength {
    my $self = shift;
    $self->{'maxlength'} = shift;
}

sub maxlength {
    my $self = shift;
    return $self->{'maxlength'};
}

sub jobs_completed {
    my $self = shift;
    return $self->{'jobs_completed'};
}

sub in_hostgroups {
    # Input:
    #   @hostgroups = the hostgroups to look for
    # Returns:
    #   true if intersection of @hostgroups and the hostgroups of this
    #        SSHLogin is non-empty
    my $self = shift;
    return grep { defined $self->{'hostgroups'}{$_} } @_;
}

sub hostgroups {
    my $self = shift;
    return keys %{$self->{'hostgroups'}};
}

sub inc_jobs_completed {
    my $self = shift;
    $self->{'jobs_completed'}++;
    $Global::total_completed++;
}

sub set_max_jobs_running {
    my $self = shift;
    if(defined $self->{'max_jobs_running'}) {
        $Global::max_jobs_running -= $self->{'max_jobs_running'};
    }
    $self->{'max_jobs_running'} = shift;
    if(defined $self->{'max_jobs_running'}) {
        # max_jobs_running could be resat if -j is a changed file
        $Global::max_jobs_running += $self->{'max_jobs_running'};
    }
    # Initialize orig to the first non-zero value that comes around
    $self->{'orig_max_jobs_running'} ||= $self->{'max_jobs_running'};
}

sub memfree {
    # Returns:
    #   $memfree in bytes
    my $self = shift;
    $self->memfree_recompute();
    return (not defined $self->{'memfree'} or $self->{'memfree'})
}

sub memfree_recompute {
    my $self = shift;
    my $script = memfreescript();

    # TODO add sshlogin and backgrounding
    # Run the script twice if it gives 0 (typically intermittent error)
    $self->{'memfree'} = ::qqx($script) || ::qqx($script);
    if(not $self->{'memfree'}) {
	::die_bug("Less than 1 byte free");
    }
    #::debug("mem","New free:",$self->{'memfree'}," ");
}

{
    my $script;

    sub memfreescript {
	# Returns:
	#   shellscript for giving available memory in bytes
	if(not $script) {
	    my %script_of = (
		# /proc/meminfo
		# MemFree:          7012 kB
		# Buffers:         19876 kB
		# Cached:         431192 kB
		# SwapCached:          0 kB
		"linux" =>
		q[ print 1024 * qx{ ].
		q[   awk '/^((Swap)?Cached|MemFree|Buffers):/ ].
		q[     { sum += \$2} END { print sum }' ].
		q[   /proc/meminfo } ],
		# $ vmstat 1 1
		#     procs           memory                   page                              faults       cpu
		# r     b     w      avm    free   re   at    pi   po    fr   de    sr     in     sy    cs  us sy id
		# 1     0     0   242793  389737    5    1     0    0     0    0     0    107    978    60   1  1 99
		"hpux" =>
		q[ print (((reverse `vmstat 1 1`)[0] ].
		q[   =~ /(?:\d+\D+){4}(\d+)/)[0]*1024) ],
		# $ vmstat 1 2
		# kthr      memory            page            disk          faults      cpu
		# r b w   swap  free  re  mf pi po fr de sr s3 s4 -- --   in   sy   cs us sy id
		# 0 0 0 6496720 5170320 68 260 8 2  1  0  0 -0  3  0  0  309 1371  255  1  2 97
		# 0 0 0 6434088 5072656 7 15  8  0  0  0  0  0 261 0  0 1889 1899 3222  0  8 92
		#
		# The second free value is correct
		"solaris" =>
		q[ print (((reverse `vmstat 1 2`)[0] ].
		q[   =~ /(?:\d+\D+){4}(\d+)/)[0]*1024) ],
		"freebsd" => q{
			for(qx{/sbin/sysctl -a}) {
			    if (/^([^:]+):\s+(.+)\s*$/s) {
				$sysctl->{$1} = $2;
			    }
			}
			print $sysctl->{"hw.pagesize"} *
			    ($sysctl->{"vm.stats.vm.v_cache_count"}
			     + $sysctl->{"vm.stats.vm.v_inactive_count"}
			     + $sysctl->{"vm.stats.vm.v_free_count"});
		    },
		# Mach Virtual Memory Statistics: (page size of 4096 bytes)
		# Pages free:                         198061.
		# Pages active:                       159701.
		# Pages inactive:                      47378.
		# Pages speculative:                   29707.
		# Pages wired down:                    89231.
		# "Translation faults":            928901425.
		# Pages copy-on-write:             156988239.
		# Pages zero filled:               271267894.
		# Pages reactivated:                   48895.
	        # Pageins:                           1798068.
	        # Pageouts:                              257.
		# Object cache: 6603 hits of 1713223 lookups (0% hit rate)
		'darwin' =>
		q[ $vm = `vm_stat`;
		  print (($vm =~ /page size of (\d+)/)[0] *
		  (($vm =~ /Pages free:\s+(\d+)/)[0] +
		   ($vm =~ /Pages inactive:\s+(\d+)/)[0]));
		],
		);
	    my $perlscript = "";
	    # Make a perl script that detects the OS ($^O) and runs
	    # the appropriate command
	    for my $os (keys %script_of) {
		$perlscript .= 'if($^O eq "'.$os.'") { '.$script_of{$os}.'}';
	    }
	    $perlscript =~ s/[\t\n ]+/ /g;
	    $script = "perl -e " . ::shell_quote_scalar($perlscript);
	}
	return $script;
    }
}

sub limit {
    # Returns:
    #  0 = Below limit. Start another job.
    #  1 = Over limit. Start no jobs.
    #  2 = Kill youngest job
    my $self = shift;

    if(not defined $self->{'limitscript'}) {
	my %limitscripts =
	    ("io" => q!
	     io() {
	         limit=$1;
                 io_file=$2;
	         # Do the measurement in the background
	         (tmp=$(tempfile);
	         LANG=C iostat -x 1 2 > $tmp;
	         mv $tmp $io_file) &
	         perl -e '-e $ARGV[0] or exit(1);
                   for(reverse <>) {
                     /Device:/ and last;
                     /(\S+)$/ and $max = $max > $1 ? $max : $1; }
                   exit ($max < '$limit')' $io_file;
	     };
             export -f io;
             io %s %s
             !,
	     "mem" => q!
             mem() {
		 limit=$1;
		 awk '/^((Swap)?Cached|MemFree|Buffers):/{ sum += $2}
                      END {
                         if (sum*1024 < '$limit'/2) { exit 2; }
                         else { exit (sum*1024 < '$limit') }
                      }' /proc/meminfo;
             };
             export -f mem;
	     mem %s;
             !,
     	     "load" => q!
	     load() {
	     	 limit=$1;
	     	 ps ax -o state,command |
	     	     grep -E '^[DOR].[^[]' |
	     	     wc -l |
	     	 perl -ne 'exit ('$limit' < $_)';
	     };
	     export -f load;
	     load %s;
	     !,
	    );
	my ($cmd,@args) = split /\s+/,$opt::limit;
	if($limitscripts{$cmd}) {
	    my $tmpfile = ::tmpname("parlmt");
	    ++$Global::unlink{$tmpfile};
	    $self->{'limitscript'} =
	    ::spacefree(1, sprintf($limitscripts{$cmd},
				   ::multiply_binary_prefix(@args),$tmpfile));
	} else {
	    $self->{'limitscript'} = $opt::limit;
	}
    }

    my %env = %ENV;
    local %ENV = %env;
    $ENV{'SSHLOGIN'} = $self->string();
    system($Global::shell,"-c",$self->{'limitscript'});
    ::debug("limit","limit `".$self->{'limitscript'}."` result ".($?>>8)."\n");
    return $?>>8;
}


sub swapping {
    my $self = shift;
    my $swapping = $self->swap_activity();
    return (not defined $swapping or $swapping)
}

sub swap_activity {
    # If the currently known swap activity is too old:
    #   Recompute a new one in the background
    # Returns:
    #   last swap activity computed
    my $self = shift;
    # Should we update the swap_activity file?
    my $update_swap_activity_file = 0;
    if(-r $self->{'swap_activity_file'}) {
        open(my $swap_fh, "<", $self->{'swap_activity_file'}) || ::die_bug("swap_activity_file-r");
        my $swap_out = <$swap_fh>;
        close $swap_fh;
        if($swap_out =~ /^(\d+)$/) {
            $self->{'swap_activity'} = $1;
            ::debug("swap", "New swap_activity: ", $self->{'swap_activity'});
        }
        ::debug("swap", "Last update: ", $self->{'last_swap_activity_update'});
        if(time - $self->{'last_swap_activity_update'} > 10) {
            # last swap activity update was started 10 seconds ago
            ::debug("swap", "Older than 10 sec: ", $self->{'swap_activity_file'});
            $update_swap_activity_file = 1;
        }
    } else {
        ::debug("swap", "No swap_activity file: ", $self->{'swap_activity_file'});
        $self->{'swap_activity'} = undef;
        $update_swap_activity_file = 1;
    }
    if($update_swap_activity_file) {
        ::debug("swap", "Updating swap_activity file ", $self->{'swap_activity_file'});
        $self->{'last_swap_activity_update'} = time;
	my $dir = ::dirname($self->{'swap_activity_file'});
	-d $dir or eval { File::Path::mkpath($dir); };
        my $swap_activity;
	$swap_activity = swapactivityscript();
        if($self->{'string'} ne ":") {
            $swap_activity = $self->sshcommand() . " " . $self->serverlogin() . " " .
		::shell_quote_scalar($swap_activity);
        }
        # Run swap_activity measuring.
        # As the command can take long to run if run remote
        # save it to a tmp file before moving it to the correct file
        my $file = $self->{'swap_activity_file'};
        my ($dummy_fh, $tmpfile) = ::tmpfile(SUFFIX => ".swp");
	::debug("swap", "\n", $swap_activity, "\n");
        ::qqx("($swap_activity > $tmpfile && mv $tmpfile $file || rm $tmpfile &)");
    }
    return $self->{'swap_activity'};
}

{
    my $script;

    sub swapactivityscript {
	# Returns:
	#   shellscript for detecting swap activity
	#
	# arguments for vmstat are OS dependant
	# swap_in and swap_out are in different columns depending on OS
	#
	if(not $script) {
	    my %vmstat = (
		# linux: $7*$8
		# $ vmstat 1 2
		# procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
		#  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
		#  5  0  51208 1701096 198012 18857888    0    0    37   153   28   19 56 11 33  1
		#  3  0  51208 1701288 198012 18857972    0    0     0     0 3638 10412 15  3 82  0
		'linux' => ['vmstat 1 2 | tail -n1', '$7*$8'],

		# solaris: $6*$7
		# $ vmstat -S 1 2
		#  kthr      memory            page            disk          faults      cpu
		#  r b w   swap  free  si  so pi po fr de sr s3 s4 -- --   in   sy   cs us sy id
		#  0 0 0 4628952 3208408 0  0  3  1  1  0  0 -0  2  0  0  263  613  246  1  2 97
		#  0 0 0 4552504 3166360 0  0  0  0  0  0  0  0  0  0  0  246  213  240  1  1 98
		'solaris' => ['vmstat -S 1 2 | tail -1', '$6*$7'],

		# darwin (macosx): $21*$22
		# $ vm_stat -c 2 1
		# Mach Virtual Memory Statistics: (page size of 4096 bytes)
		#     free   active   specul inactive throttle    wired  prgable   faults     copy    0fill reactive   purged file-backed anonymous cmprssed cmprssor  dcomprs   comprs  pageins  pageout  swapins swapouts
		#   346306   829050    74871   606027        0   240231    90367  544858K 62343596  270837K    14178   415070      570102    939846      356      370      116      922  4019813        4        0        0
		#   345740   830383    74875   606031        0   239234    90369     2696      359      553        0        0      570110    941179      356      370        0        0        0        0        0        0
		'darwin' => ['vm_stat -c 2 1 | tail -n1', '$21*$22'],

		# ultrix: $12*$13
		# $ vmstat -S 1 2
		#  procs      faults    cpu      memory              page             disk
		#  r b w   in  sy  cs us sy id  avm  fre  si so  pi  po  fr  de  sr s0
		#  1 0 0    4  23   2  3  0 97 7743 217k   0  0   0   0   0   0   0  0
		#  1 0 0    6  40   8  0  1 99 7743 217k   0  0   3   0   0   0   0  0
		'ultrix' => ['vmstat -S 1 2 | tail -1', '$12*$13'],

		# aix: $6*$7
		# $ vmstat 1 2
		# System configuration: lcpu=1 mem=2048MB
		#
		# kthr    memory              page              faults        cpu
		# ----- ----------- ------------------------ ------------ -----------
		#  r  b   avm   fre  re  pi  po  fr   sr  cy  in   sy  cs us sy id wa
		#  0  0 333933 241803   0   0   0   0    0   0  10  143  90  0  0 99  0
		#  0  0 334125 241569   0   0   0   0    0   0  37 5368 184  0  9 86  5
		'aix' => ['vmstat 1 2 | tail -n1', '$6*$7'],

		# freebsd: $8*$9
		# $ vmstat -H 1 2
		#  procs      memory      page                    disks     faults         cpu
		#  r b w     avm    fre   flt  re  pi  po    fr  sr ad0 ad1   in   sy   cs us sy id
		#  1 0 0  596716   19560    32   0   0   0    33   8   0   0   11  220  277  0  0 99
		#  0 0 0  596716   19560     2   0   0   0     0   0   0   0   11  144  263  0  1 99
		'freebsd' => ['vmstat -H 1 2 | tail -n1', '$8*$9'],

		# mirbsd: $8*$9
		# $ vmstat 1 2
		#  procs   memory        page                    disks     traps         cpu
		#  r b w    avm    fre   flt  re  pi  po  fr  sr wd0 cd0  int   sys   cs us sy id
		#  0 0 0  25776 164968    34   0   0   0   0   0   0   0  230   259   38  4  0 96
		#  0 0 0  25776 164968    24   0   0   0   0   0   0   0  237   275   37  0  0 100
		'mirbsd' => ['vmstat 1 2 | tail -n1', '$8*$9'],

		# netbsd: $7*$8
		# $ vmstat 1 2
		#  procs    memory      page                       disks   faults      cpu
		#  r b      avm    fre  flt  re  pi   po   fr   sr w0 w1   in   sy  cs us sy id
		#  0 0   138452   6012   54   0   0    0    1    2  3  0    4  100  23  0  0 100
		#  0 0   138456   6008    1   0   0    0    0    0  0  0    7   26  19  0 0 100
		'netbsd' => ['vmstat 1 2 | tail -n1', '$7*$8'],

		# openbsd: $8*$9
		# $ vmstat 1 2
		#  procs    memory       page                    disks    traps          cpu
		#  r b w    avm     fre  flt  re  pi  po  fr  sr wd0 wd1  int   sys   cs us sy id
		#  0 0 0  76596  109944   73   0   0   0   0   0   0   1    5   259   22  0  1 99
		#  0 0 0  76604  109936   24   0   0   0   0   0   0   0    7   114   20  0  1 99
		'openbsd' => ['vmstat 1 2 | tail -n1', '$8*$9'],

		# hpux: $8*$9
		# $ vmstat 1 2
		#          procs           memory                   page                              faults       cpu
		#     r     b     w      avm    free   re   at    pi   po    fr   de    sr     in     sy    cs  us sy id
		#     1     0     0   247211  216476    4    1     0    0     0    0     0    102  73005    54   6 11 83
		#     1     0     0   247211  216421   43    9     0    0     0    0     0    144   1675    96  25269512791222387000 25269512791222387000 105
		'hpux' => ['vmstat 1 2 | tail -n1', '$8*$9'],

		# dec_osf (tru64): $11*$12
		# $ vmstat  1 2
		# Virtual Memory Statistics: (pagesize = 8192)
		#   procs      memory        pages                            intr       cpu
		#   r   w   u  act free wire fault  cow zero react  pin pout  in  sy  cs us sy id
		#   3 181  36  51K 1895 8696  348M  59M 122M   259  79M    0   5 218 302  4  1 94
		#   3 181  36  51K 1893 8696     3   15   21     0   28    0   4  81 321  1  1 98
		'dec_osf' => ['vmstat 1 2 | tail -n1', '$11*$12'],

		# gnu (hurd): $7*$8
		# $ vmstat -k 1 2
		# (pagesize: 4, size: 512288, swap size: 894972)
		#   free   actv  inact  wired   zeroed  react    pgins   pgouts  pfaults  cowpfs hrat    caobj  cache swfree
		# 371940  30844  89228  20276   298348      0    48192    19016   756105   99808  98%      876  20628 894972
		# 371940  30844  89228  20276       +0     +0       +0       +0      +42      +2  98%      876  20628 894972
		'gnu' => ['vmstat -k 1 2 | tail -n1', '$7*$8'],

		# -nto (qnx has no swap)
		#-irix
		#-svr5 (scosysv)
		);
	    my $perlscript = "";
	    # Make a perl script that detects the OS ($^O) and runs
	    # the appropriate vmstat command
	    for my $os (keys %vmstat) {
		$vmstat{$os}[1] =~ s/\$/\\\\\\\$/g; # $ => \\\$
		$perlscript .= 'if($^O eq "'.$os.'") { print `'.$vmstat{$os}[0].' | awk "{print ' .
		    $vmstat{$os}[1] . '}"` }';
	    }
	    $script = "perl -e " . ::shell_quote_scalar($perlscript);
	}
	return $script;
    }
}

sub too_fast_remote_login {
    my $self = shift;
    if($self->{'last_login_at'} and $self->{'time_to_login'}) {
	# sshd normally allows 10 simultaneous logins
	# A login takes time_to_login
	# So time_to_login/5 should be safe
	# If now <= last_login + time_to_login/5: Then it is too soon.
	my $too_fast = (::now() <= $self->{'last_login_at'}
			+ $self->{'time_to_login'}/5);
	::debug("run", "Too fast? $too_fast ");
	return $too_fast;
    } else {
	# No logins so far (or time_to_login not computed): it is not too fast
	return 0;
    }
}

sub last_login_at {
    my $self = shift;
    return $self->{'last_login_at'};
}

sub set_last_login_at {
    my $self = shift;
    $self->{'last_login_at'} = shift;
}

sub loadavg_too_high {
    my $self = shift;
    my $loadavg = $self->loadavg();
    return (not defined $loadavg or
            $loadavg > $self->max_loadavg());
}

{
    my $cmd;
    sub loadavg_cmd {
	if(not $cmd) {
	    # aix => "ps -ae -o state,command" # state wrong
	    # bsd => "ps ax -o state,command"
	    # sysv => "ps -ef -o s -o comm"
	    # cygwin => perl -ne 'close STDERR; /Name/ and print"\n"; \
	    #    /(Name|Pid|Ppid|State):\s+(\S+)/ and print "$2\t";' /proc/*/status |
	    #    awk '{print $2,$1}'
	    # dec_osf => bsd
	    # dragonfly => bsd
	    # freebsd => bsd
	    # gnu => bsd
	    # hpux => ps -el|awk '{print $2,$14,$15}'
	    # irix => ps -ef -o state -o comm
	    # linux => bsd
	    # minix => ps el|awk '{print \$1,\$11}'
	    # mirbsd => bsd
	    # netbsd => bsd
	    # openbsd => bsd
	    # solaris => sysv
	    # svr5 => sysv
	    # ultrix => ps -ax | awk '{print $3,$5}'
	    # unixware => ps -el|awk '{print $2,$14,$15}'
	    my $ps = ::spacefree(1,q{
		$sysv="ps -ef -o s -o comm";
		$sysv2="ps -ef -o state -o comm";
		$bsd="ps ax -o state,command";
		# Treat threads as processes
		$bsd2="ps axH -o state,command";
		$psel="ps -el|awk '{ print \$2,\$14,\$15 }'";
		$cygwin=q{ perl -ne 'close STDERR; /Name/ and print"\n";
                    /(Name|Pid|Ppid|State):\s+(\S+)/ and print "$2\t";' /proc/*/status |
                    awk '{print $2,$1}' };
		$dummy="echo S COMMAND;echo R dummy";
		%ps=(
		    # TODO Find better code for AIX
		    'aix' => "uptime",
		    'cygwin' => $cygwin,
		    'darwin' => $bsd,
		    'dec_osf' => $sysv2,
		    'dragonfly' => $bsd,
		    'freebsd' => $bsd2,
		    'gnu' => $bsd,
		    'hpux' => $psel,
		    'irix' => $sysv2,
		    'linux' => $bsd2,
		    'minix' => "ps el|awk '{print \$1,\$11}'",
		    'mirbsd' => $bsd,
		    'msys' => $sysv,
	            'MSWin32' => $sysv,
		    'netbsd' => $bsd,
		    'nto' => $dummy,
		    'openbsd' => $bsd,
		    'solaris' => $sysv,
		    'svr5' => $psel,
		    'ultrix' => "ps -ax | awk '{print \$3,\$5}'",
		    );
		print `$ps{$^O}`;
	    });
	    # The command is too long for csh, so base64_wrap the command
	    $cmd = Job::base64_wrap($ps);
	}
	return $cmd;
    }
}


sub loadavg {
    # If the currently know loadavg is too old:
    #   Recompute a new one in the background
    # The load average is computed as the number of processes waiting for disk
    # or CPU right now. So it is the server load this instant and not averaged over
    # several minutes. This is needed so GNU Parallel will at most start one job
    # that will push the load over the limit.
    #
    # Returns:
    #   $last_loadavg = last load average computed (undef if none)
    my $self = shift;
    # Should we update the loadavg file?
    my $update_loadavg_file = 0;
    if(open(my $load_fh, "<", $self->{'loadavg_file'})) {
	local $/; # $/ = undef => slurp whole file
        my $load_out = <$load_fh>;
        close $load_fh;
	if($load_out =~ /\S/) {
	    # Content can be empty if ~/ is on NFS
	    # due to reading being non-atomic.
	    #
	    # Count lines starting with D,O,R but command does not start with [
	    my $load =()= ($load_out=~/(^\s?[DOR]\S* +(?=[^\[])\S)/gm);
	    if($load > 0) {
		# load is overestimated by 1
		$self->{'loadavg'} = $load - 1;
		::debug("load", "New loadavg: ", $self->{'loadavg'},"\n");
	    } elsif ($load_out=~/average: (\d+.\d+)/) {
		# AIX does not support instant load average
		# 04:11AM   up 21 days,  12:55,  1 user,  load average: 1.85, 1.57, 1.55
		$self->{'loadavg'} = $1;
	    } else {
		::die_bug("loadavg_invalid_content: " .
			  $self->{'loadavg_file'} . "\n$load_out");
	    }
	}
	$update_loadavg_file = 1;
    } else {
        ::debug("load", "No loadavg file: ", $self->{'loadavg_file'});
        $self->{'loadavg'} = undef;
        $update_loadavg_file = 1;
    }
    if($update_loadavg_file) {
        ::debug("load", "Updating loadavg file", $self->{'loadavg_file'}, "\n");
        $self->{'last_loadavg_update'} = time;
	my $dir = ::dirname($self->{'swap_activity_file'});
	-d $dir or eval { File::Path::mkpath($dir); };
        -w $dir or ::die_bug("Cannot write to $dir");
        my $cmd = "";
        if($self->{'string'} ne ":") {
	    $cmd = $self->sshcommand() . " " . $self->serverlogin() . " " .
		::shell_quote_scalar(loadavg_cmd());
	} else {
	    $cmd .= loadavg_cmd();
	}
        # As the command can take long to run if run remote
        # save it to a tmp file before moving it to the correct file
        ::debug("load", "Cmd: ", $cmd,"\n");
        my $file = $self->{'loadavg_file'};
        my ($dummy_fh, $tmpfile) = ::tmpfile(SUFFIX => ".loa");
        ::qqx("($cmd > $tmpfile && mv $tmpfile $file || rm $tmpfile & )");
    }
    return $self->{'loadavg'};
}

sub max_loadavg {
    my $self = shift;
    # If --load is a file it might be changed
    if($Global::max_load_file) {
	my $mtime = (stat($Global::max_load_file))[9];
	if($mtime > $Global::max_load_file_last_mod) {
	    $Global::max_load_file_last_mod = $mtime;
	    for my $sshlogin (values %Global::host) {
		$sshlogin->set_max_loadavg(undef);
	    }
	}
    }
    if(not defined $self->{'max_loadavg'}) {
        $self->{'max_loadavg'} =
            $self->compute_max_loadavg($opt::load);
    }
    ::debug("load", "max_loadavg: ", $self->string(), " ", $self->{'max_loadavg'});
    return $self->{'max_loadavg'};
}

sub set_max_loadavg {
    my $self = shift;
    $self->{'max_loadavg'} = shift;
}

sub compute_max_loadavg {
    # Parse the max loadaverage that the user asked for using --load
    # Returns:
    #   max loadaverage
    my $self = shift;
    my $loadspec = shift;
    my $load;
    if(defined $loadspec) {
        if($loadspec =~ /^\+(\d+)$/) {
            # E.g. --load +2
            my $j = $1;
            $load =
                $self->ncpus() + $j;
        } elsif ($loadspec =~ /^-(\d+)$/) {
            # E.g. --load -2
            my $j = $1;
            $load =
                $self->ncpus() - $j;
        } elsif ($loadspec =~ /^(\d+)\%$/) {
            my $j = $1;
            $load =
                $self->ncpus() * $j / 100;
        } elsif ($loadspec =~ /^(\d+(\.\d+)?)$/) {
            $load = $1;
        } elsif (-f $loadspec) {
            $Global::max_load_file = $loadspec;
            $Global::max_load_file_last_mod = (stat($Global::max_load_file))[9];
            if(open(my $in_fh, "<", $Global::max_load_file)) {
                my $opt_load_file = join("",<$in_fh>);
                close $in_fh;
                $load = $self->compute_max_loadavg($opt_load_file);
            } else {
                ::error("Cannot open $loadspec.");
                ::wait_and_exit(255);
            }
        } else {
            ::error("Parsing of --load failed.");
            ::die_usage();
        }
        if($load < 0.01) {
            $load = 0.01;
        }
    }
    return $load;
}

sub time_to_login {
    my $self = shift;
    return $self->{'time_to_login'};
}

sub set_time_to_login {
    my $self = shift;
    $self->{'time_to_login'} = shift;
}

sub max_jobs_running {
    my $self = shift;
    if(not defined $self->{'max_jobs_running'}) {
        my $nproc = $self->compute_number_of_processes($opt::jobs);
        $self->set_max_jobs_running($nproc);
    }
    return $self->{'max_jobs_running'};
}

sub orig_max_jobs_running {
    my $self = shift;
    return $self->{'orig_max_jobs_running'};
}

sub compute_number_of_processes {
    # Number of processes wanted and limited by system resources
    # Returns:
    #   Number of processes
    my $self = shift;
    my $opt_P = shift;
    my $wanted_processes = $self->user_requested_processes($opt_P);
    if(not defined $wanted_processes) {
        $wanted_processes = $Global::default_simultaneous_sshlogins;
    }
    ::debug("load", "Wanted procs: $wanted_processes\n");
    my $system_limit =
        $self->processes_available_by_system_limit($wanted_processes);
    ::debug("load", "Limited to procs: $system_limit\n");
    return $system_limit;
}

{
    my @children;
    my $max_system_proc_reached;
    my $more_filehandles;
    my %fh;
    my $tmpfhname;
    my $count_jobs_already_read;
    my @jobs;
    my $job;
    my @args;
    my $arg;

    sub reserve_filehandles {
	# Reserves filehandle
	my $n = shift;
	for (1..$n) {
	    $more_filehandles &&= open($fh{$tmpfhname++}, "<", "/dev/null");
	}
    }

    sub reserve_process {
	# Spawn a dummy process
	my $child;
	if($child = fork()) {
	    push @children, $child;
	    $Global::unkilled_children{$child} = 1;
	} elsif(defined $child) {
	    # This is the child
	    # The child takes one process slot
	    # It will be killed later
	    $SIG{'TERM'} = $Global::original_sig{'TERM'};
	    if($^O eq "cygwin") {
		# The exec does not work on Cygwin
		sleep 10101010;
	    } else {
		# 'exec sleep' takes less RAM than sleeping in perl
		exec 'sleep', 10101;
	    }
	    exit(0);
	} else {
	    # Failed to spawn
            $max_system_proc_reached = 1;
	}
    }

    sub get_args_or_jobs {
	# Get an arg or a job (depending on mode)
	if($Global::semaphore or ($opt::pipe and not $opt::tee)) {
	    # Skip: No need to get args
	    return 1;
	} elsif(defined $opt::retries and $count_jobs_already_read) {
	    # For retries we may need to run all jobs on this sshlogin
	    # so include the already read jobs for this sshlogin
	    $count_jobs_already_read--;
	    return 1;
	} else {
	    if($opt::X or $opt::m) {
		# The arguments may have to be re-spread over several jobslots
		# So pessimistically only read one arg per jobslot
		# instead of a full commandline
		if($Global::JobQueue->{'commandlinequeue'}->{'arg_queue'}->empty()) {
		    if($Global::JobQueue->empty()) {
			return 0;
		    } else {
			$job = $Global::JobQueue->get();
			push(@jobs, $job);
			return 1;
		    }
		} else {
		    $arg = $Global::JobQueue->{'commandlinequeue'}->{'arg_queue'}->get();
		    push(@args, $arg);
		    return 1;
		}
	    } else {
		# If there are no more command lines, then we have a process
		# per command line, so no need to go further
		if($Global::JobQueue->empty()) {
		    return 0;
		} else {
		    $job = $Global::JobQueue->get();
		    push(@jobs, $job);
		    return 1;
		}
	    }
	}
    }

    sub cleanup {
	# Cleanup: Close the files
	for (values %fh) { close $_ }
	# Cleanup: Kill the children
	for my $pid (@children) {
	    kill 9, $pid;
	    waitpid($pid,0);
	    delete $Global::unkilled_children{$pid};
	}
	# Cleanup: Unget the command_lines or the @args
	$Global::JobQueue->{'commandlinequeue'}->{'arg_queue'}->unget(@args);
	@args = ();
	$Global::JobQueue->unget(@jobs);
	@jobs = ();
    }

    sub processes_available_by_system_limit {
	# If the wanted number of processes is bigger than the system limits:
	# Limit them to the system limits
	# Limits are: File handles, number of input lines, processes,
	# and taking > 1 second to spawn 10 extra processes
	# Returns:
	#   Number of processes
	my $self = shift;
	my $wanted_processes = shift;
	my $system_limit = 0;
	my $slow_spawning_warning_printed = 0;
	my $time = time;
	$more_filehandles = 1;
	$tmpfhname = "TmpFhNamE";

	# perl uses 7 filehandles for something?
	# parallel uses 1 for memory_usage
	# parallel uses 4 for ?
	reserve_filehandles(12);
	# Two processes for load avg and ?
	reserve_process();
	reserve_process();

	# For --retries count also jobs already run
	$count_jobs_already_read = $Global::JobQueue->next_seq();
	my $wait_time_for_getting_args = 0;
	my $start_time = time;
	while(1) {
	    $system_limit >= $wanted_processes and last;
	    not $more_filehandles and last;
	    $max_system_proc_reached and last;

	    my $before_getting_arg = time;
	    if(!$Global::dummy_jobs) {
		get_args_or_jobs() or last;
	    }
	    $wait_time_for_getting_args += time - $before_getting_arg;
	    $system_limit++;

	    # Every simultaneous process uses 2 filehandles to write to
	    # and 2 filehandles to read from
	    reserve_filehandles(4);

	    # System process limit
	    reserve_process();

	    my $forktime = time - $time - $wait_time_for_getting_args;
	    ::debug("run", "Time to fork $system_limit procs: $wait_time_for_getting_args ",
		    $forktime,
		    " (processes so far: ", $system_limit,")\n");
	    if($system_limit > 10 and
	       $forktime > 1 and
	       $forktime > $system_limit * 0.01
	       and not $slow_spawning_warning_printed) {
		# It took more than 0.01 second to fork a processes on avg.
		# Give the user a warning. He can press Ctrl-C if this
		# sucks.
		::warning("Starting $system_limit processes took > $forktime sec.",
			  "Consider adjusting -j. Press CTRL-C to stop.");
		$slow_spawning_warning_printed = 1;
	    }
	}
	cleanup();

	if($system_limit < $wanted_processes) {
	    # The system_limit is less than the wanted_processes
	    if($system_limit < 1 and not $Global::JobQueue->empty()) {
		::warning("Cannot spawn any jobs. ".
			  "Raising ulimit -u or 'nproc' in /etc/security/limits.conf",
			  "or /proc/sys/kernel/pid_max may help.");
		::wait_and_exit(255);
	    }
	    if(not $more_filehandles) {
		::warning("Only enough file handles to run ".
			  $system_limit. " jobs in parallel.",
			  "Running 'parallel -j0 -N $system_limit --pipe parallel -j0' or",
			  "raising 'ulimit -n' or 'nofile' in /etc/security/limits.conf",
			  "or /proc/sys/fs/file-max may help.");
	    }
	    if($max_system_proc_reached) {
		::warning("Only enough available processes to run ".
			  $system_limit. " jobs in parallel.",
			  "Raising ulimit -u or /etc/security/limits.conf ",
			  "or /proc/sys/kernel/pid_max may help.");
	    }
	}
	if($] == 5.008008 and $system_limit > 1000) {
	    # https://savannah.gnu.org/bugs/?36942
	    $system_limit = 1000;
	}
	if($Global::JobQueue->empty()) {
	    $system_limit ||= 1;
	}
	if($self->string() ne ":" and
	   $system_limit > $Global::default_simultaneous_sshlogins) {
	    $system_limit =
		$self->simultaneous_sshlogin_limit($system_limit);
	}
	return $system_limit;
    }
}

sub simultaneous_sshlogin_limit {
    # Test by logging in wanted number of times simultaneously
    # Returns:
    #   min($wanted_processes,$working_simultaneous_ssh_logins-1)
    my $self = shift;
    my $wanted_processes = shift;
    if($self->{'time_to_login'}) {
	return $wanted_processes;
    }

    # Try twice because it guesses wrong sometimes
    # Choose the minimal
    my $ssh_limit =
        ::min($self->simultaneous_sshlogin($wanted_processes),
	      $self->simultaneous_sshlogin($wanted_processes));
    if($ssh_limit < $wanted_processes) {
        my $serverlogin = $self->serverlogin();
        ::warning("ssh to $serverlogin only allows ".
		  "for $ssh_limit simultaneous logins.",
		  "You may raise this by changing ".
		  "/etc/ssh/sshd_config:MaxStartups and MaxSessions on $serverlogin.",
		  "You can also try --sshdelay 0.1",
		  "Using only ".($ssh_limit-1)." connections ".
		  "to avoid race conditions.");
	# Race condition can cause problem if using all sshs.
	if($ssh_limit > 1) { $ssh_limit -= 1; }
    }
    return $ssh_limit;
}

sub simultaneous_sshlogin {
    # Using $sshlogin try to see if we can do $wanted_processes
    # simultaneous logins
    # (ssh host echo simultaneouslogin & ssh host echo simultaneouslogin & ...)|grep simul|wc -l
    # Returns:
    #   Number of succesful logins
    local $/ = "\n";
    my $self = shift;
    my $wanted_processes = shift;
    my $sshcmd = $self->sshcommand();
    my $serverlogin = $self->serverlogin();
    my $sshdelay = $opt::sshdelay ? "sleep $opt::sshdelay;" : "";
    # TODO sh -c wrapper to work for csh
    my $cmd = "$sshdelay$sshcmd $serverlogin -- echo simultaneouslogin </dev/null 2>&1 &"x$wanted_processes;
    ::debug("init", "Trying $wanted_processes logins at $serverlogin\n");
    open (my $simul_fh, "-|", "($cmd)|grep simultaneouslogin | wc -l") or
	::die_bug("simultaneouslogin");
    my $ssh_limit = <$simul_fh>;
    close $simul_fh;
    chomp $ssh_limit;
    return $ssh_limit;
}

sub set_ncpus {
    my $self = shift;
    $self->{'ncpus'} = shift;
}

sub user_requested_processes {
    # Parse the number of processes that the user asked for using -j
    # Returns:
    #   the number of processes to run on this sshlogin
    my $self = shift;
    my $opt_P = shift;
    my $processes;
    if(defined $opt_P) {
        if($opt_P =~ /^\+(\d+)$/) {
            # E.g. -P +2
            my $j = $1;
            $processes =
                $self->ncpus() + $j;
        } elsif ($opt_P =~ /^-(\d+)$/) {
            # E.g. -P -2
            my $j = $1;
            $processes =
                $self->ncpus() - $j;
        } elsif ($opt_P =~ /^(\d+(\.\d+)?)\%$/) {
            # E.g. -P 10.5%
            my $j = $1;
            $processes =
                $self->ncpus() * $j / 100;
        } elsif ($opt_P =~ /^(\d+)$/) {
            $processes = $1;
            if($processes == 0) {
                # -P 0 = infinity (or at least close)
                $processes = $Global::infinity;
            }
        } elsif (-f $opt_P) {
            $Global::max_procs_file = $opt_P;
            if(open(my $in_fh, "<", $Global::max_procs_file)) {
                my $opt_P_file = join("",<$in_fh>);
                close $in_fh;
                $processes = $self->user_requested_processes($opt_P_file);
            } else {
                ::error("Cannot open $opt_P.");
                ::wait_and_exit(255);
            }
        } else {
            ::error("Parsing of --jobs/-j/--max-procs/-P failed.");
            ::die_usage();
        }
	$processes = ::ceil($processes);
    }
    return $processes;
}

sub ncpus {
    local $/ = "\n";
    my $self = shift;
    if(not defined $self->{'ncpus'}) {
        my $sshcmd = $self->sshcommand();
        my $serverlogin = $self->serverlogin();
        if($serverlogin eq ":") {
            if($opt::use_cpus_instead_of_cores) {
                $self->{'ncpus'} = no_of_cpus();
            } else {
                $self->{'ncpus'} = no_of_cores();
            }
        } else {
            my $ncpu;
            if($opt::use_cpus_instead_of_cores) {
                $ncpu = ::qqx("echo|$sshcmd $serverlogin -- parallel --number-of-cpus");
            } else {
		::debug("init",qq(echo|$sshcmd $serverlogin -- parallel --number-of-cores\n));
                $ncpu = ::qqx("echo|$sshcmd $serverlogin -- parallel --number-of-cores");
            }
	    chomp $ncpu;
            if($ncpu =~ /^\s*[0-9]+\s*$/s) {
                $self->{'ncpus'} = $ncpu;
            } else {
                ::warning("Could not figure out ".
			  "number of cpus on $serverlogin ($ncpu). Using 1.");
                $self->{'ncpus'} = 1;
            }
        }
    }
    return $self->{'ncpus'};
}

sub no_of_cpus {
    # Returns:
    #   Number of physical CPUs
    local $/ = "\n"; # If delimiter is set, then $/ will be wrong
    my $no_of_cpus;
    if ($^O eq 'linux') {
        $no_of_cpus = no_of_cpus_gnu_linux() || no_of_cores_gnu_linux();
    } elsif ($^O eq 'freebsd') {
        $no_of_cpus = no_of_cpus_freebsd();
    } elsif ($^O eq 'netbsd') {
        $no_of_cpus = no_of_cpus_netbsd();
    } elsif ($^O eq 'openbsd') {
        $no_of_cpus = no_of_cpus_openbsd();
    } elsif ($^O eq 'gnu') {
        $no_of_cpus = no_of_cpus_hurd();
    } elsif ($^O eq 'darwin') {
	$no_of_cpus = no_of_cpus_darwin();
    } elsif ($^O eq 'solaris') {
        $no_of_cpus = no_of_cpus_solaris() || nproc();
    } elsif ($^O eq 'aix') {
        $no_of_cpus = no_of_cpus_aix();
    } elsif ($^O eq 'hpux') {
        $no_of_cpus = no_of_cpus_hpux();
    } elsif ($^O eq 'nto') {
        $no_of_cpus = no_of_cpus_qnx();
    } elsif ($^O eq 'svr5') {
        $no_of_cpus = no_of_cpus_openserver();
    } elsif ($^O eq 'irix') {
        $no_of_cpus = no_of_cpus_irix();
    } elsif ($^O eq 'dec_osf') {
        $no_of_cpus = no_of_cpus_tru64();
    } else {
	$no_of_cpus = (no_of_cpus_gnu_linux()
		       || no_of_cpus_freebsd()
		       || no_of_cpus_netbsd()
		       || no_of_cpus_openbsd()
		       || no_of_cpus_hurd()
		       || no_of_cpus_darwin()
		       || no_of_cpus_solaris()
		       || no_of_cpus_aix()
		       || no_of_cpus_hpux()
		       || no_of_cpus_qnx()
		       || no_of_cpus_openserver()
		       || no_of_cpus_irix()
		       || no_of_cpus_tru64()
			# Number of cores is better than no guess for #CPUs
		       || nproc()
	    );
    }
    if($no_of_cpus) {
	chomp $no_of_cpus;
        return $no_of_cpus;
    } else {
        ::warning("Cannot figure out number of cpus. Using 1.");
        return 1;
    }
}

sub no_of_cores {
    # Returns:
    #   Number of CPU cores
    local $/ = "\n"; # If delimiter is set, then $/ will be wrong
    my $no_of_cores;
    if ($^O eq 'linux') {
	$no_of_cores = no_of_cores_gnu_linux();
    } elsif ($^O eq 'freebsd') {
        $no_of_cores = no_of_cores_freebsd();
    } elsif ($^O eq 'netbsd') {
        $no_of_cores = no_of_cores_netbsd();
    } elsif ($^O eq 'openbsd') {
        $no_of_cores = no_of_cores_openbsd();
    } elsif ($^O eq 'gnu') {
        $no_of_cores = no_of_cores_hurd();
    } elsif ($^O eq 'darwin') {
	$no_of_cores = no_of_cores_darwin();
    } elsif ($^O eq 'solaris') {
	$no_of_cores = no_of_cores_solaris() || nproc();
    } elsif ($^O eq 'aix') {
        $no_of_cores = no_of_cores_aix();
    } elsif ($^O eq 'hpux') {
        $no_of_cores = no_of_cores_hpux();
    } elsif ($^O eq 'nto') {
        $no_of_cores = no_of_cores_qnx();
    } elsif ($^O eq 'svr5') {
        $no_of_cores = no_of_cores_openserver();
    } elsif ($^O eq 'irix') {
        $no_of_cores = no_of_cores_irix();
    } elsif ($^O eq 'dec_osf') {
        $no_of_cores = no_of_cores_tru64();
    } else {
	$no_of_cores = (no_of_cores_gnu_linux()
			|| no_of_cores_freebsd()
			|| no_of_cores_netbsd()
			|| no_of_cores_openbsd()
			|| no_of_cores_hurd()
			|| no_of_cores_darwin()
			|| no_of_cores_solaris()
			|| no_of_cores_aix()
			|| no_of_cores_hpux()
			|| no_of_cores_qnx()
			|| no_of_cores_openserver()
			|| no_of_cores_irix()
			|| no_of_cores_tru64()
			|| nproc()
	    );
    }
    if($no_of_cores) {
	chomp $no_of_cores;
        return $no_of_cores;
    } else {
        ::warning("Cannot figure out number of CPU cores. Using 1.");
        return 1;
    }
}

sub nproc {
    # Returns:
    #   Number of cores using `nproc`
    my $no_of_cores = ::qqx("nproc");
    return $no_of_cores;
}

sub no_of_cpus_gnu_linux {
    # Returns:
    #   Number of physical CPUs on GNU/Linux
    #   undef if not GNU/Linux
    my $no_of_cpus;
    my $no_of_cores;
    my $no_of_active_cores;
    if(-e "/proc/cpuinfo") {
        $no_of_cpus = 0;
        $no_of_cores = 0;
        my %seen;
        if(open(my $in_fh, "<", "/proc/cpuinfo")) {
	    while(<$in_fh>) {
		if(/^physical id.*[:](.*)/ and not $seen{$1}++) {
		    $no_of_cpus++;
		}
		/^processor.*[:]/i and $no_of_cores++;
	    }
	    close $in_fh;
	}
    }
    if(-e "/proc/self/status") {
	# if 'taskset' is used to limit number of cores
        if(open(my $in_fh, "<", "/proc/self/status")) {
	    while(<$in_fh>) {
		if(/^Cpus_allowed:\s*(\S+)/) {
		    my $a = $1;
		    $a =~ tr/,//d;
		    $no_of_active_cores = unpack ("%32b*", pack ("H*",$a));
		}
	    }
	    close $in_fh;
	}
    }
    return (::min($no_of_cpus || $no_of_cores,$no_of_active_cores));
}

sub no_of_cores_gnu_linux {
    # Returns:
    #   Number of CPU cores on GNU/Linux
    #   undef if not GNU/Linux
    my $no_of_cores;
    my $no_of_active_cores;
    if(-e "/proc/cpuinfo") {
        $no_of_cores = 0;
        open(my $in_fh, "<", "/proc/cpuinfo") || return undef;
        while(<$in_fh>) {
            /^processor.*[:]/i and $no_of_cores++;
        }
        close $in_fh;
    }
    if(-e "/proc/self/status") {
	# if 'taskset' is used to limit number of cores
        if(open(my $in_fh, "<", "/proc/self/status")) {
	    while(<$in_fh>) {
		if(/^Cpus_allowed:\s*(\S+)/) {
		    my $a = $1;
		    $a =~ tr/,//d;
		    $no_of_active_cores = unpack ("%32b*", pack ("H*",$a));
		}
	    }
	    close $in_fh;
	}
    }
    return (::min($no_of_cores,$no_of_active_cores));
}

sub no_of_cpus_freebsd {
    # Returns:
    #   Number of physical CPUs on FreeBSD
    #   undef if not FreeBSD
    local $/ = "\n";
    my $no_of_cpus =
	(::qqx(qq{ sysctl -a dev.cpu | grep \%parent | awk '{ print \$2 }' | uniq | wc -l | awk '{ print \$1 }' })
	 or
	 ::qqx(qq{ sysctl hw.ncpu | awk '{ print \$2 }' }));
    chomp $no_of_cpus;
    return $no_of_cpus;
}

sub no_of_cores_freebsd {
    # Returns:
    #   Number of CPU cores on FreeBSD
    #   undef if not FreeBSD
    local $/ = "\n";
    my $no_of_cores =
	(::qqx(qq{ sysctl hw.ncpu | awk '{ print \$2 }' })
	 or
	 ::qqx(qq{ sysctl -a dev.cpu | grep \%parent | awk '{ print \$2 }' | uniq | wc -l | awk '{ print \$1 }' }));
    chomp $no_of_cores;
    return $no_of_cores;
}

sub no_of_cpus_netbsd {
    # Returns:
    #   Number of physical CPUs on NetBSD
    #   undef if not NetBSD
    local $/ = "\n";
    my $no_of_cpus = ::qqx("sysctl -n hw.ncpu");
    chomp $no_of_cpus;
    return $no_of_cpus;
}

sub no_of_cores_netbsd {
    # Returns:
    #   Number of CPU cores on NetBSD
    #   undef if not NetBSD
    local $/ = "\n";
    my $no_of_cores = ::qqx("sysctl -n hw.ncpu");
    chomp $no_of_cores;
    return $no_of_cores;
}

sub no_of_cpus_openbsd {
    # Returns:
    #   Number of physical CPUs on OpenBSD
    #   undef if not OpenBSD
    local $/ = "\n";
    my $no_of_cpus = ::qqx('sysctl -n hw.ncpu');
    chomp $no_of_cpus;
    return $no_of_cpus;
}

sub no_of_cores_openbsd {
    # Returns:
    #   Number of CPU cores on OpenBSD
    #   undef if not OpenBSD
    local $/ = "\n";
    my $no_of_cores = ::qqx('sysctl -n hw.ncpu');
    chomp $no_of_cores;
    return $no_of_cores;
}

sub no_of_cpus_hurd {
    # Returns:
    #   Number of physical CPUs on HURD
    #   undef if not HURD
    local $/ = "\n";
    my $no_of_cpus = ::qqx("nproc");
    chomp $no_of_cpus;
    return $no_of_cpus;
}

sub no_of_cores_hurd {
    # Returns:
    #   Number of physical CPUs on HURD
    #   undef if not HURD
    local $/ = "\n";
    my $no_of_cores = ::qqx("nproc");
    chomp $no_of_cores;
    return $no_of_cores;
}

sub no_of_cpus_darwin {
    # Returns:
    #   Number of physical CPUs on MacOSX Darwin
    #   undef if not MacOSX Darwin
    my $no_of_cpus =
	(::qqx('sysctl -n hw.physicalcpu')
	 or
	 ::qqx(qq{ sysctl -a hw | grep [^a-z]physicalcpu[^a-z] | awk '{ print \$2 }' }));
    return $no_of_cpus;
}

sub no_of_cores_darwin {
    # Returns:
    #   Number of CPU cores on Mac Darwin
    #   undef if not Mac Darwin
    my $no_of_cores =
	(::qqx('sysctl -n hw.logicalcpu')
	 or
	 ::qqx(qq{ sysctl -a hw | grep [^a-z]logicalcpu[^a-z] | awk '{ print \$2 }' }));
    return $no_of_cores;
}

sub no_of_cpus_solaris {
    # Returns:
    #   Number of physical CPUs on Solaris
    #   undef if not Solaris
    if(-x "/usr/sbin/psrinfo") {
        my @psrinfo = ::qqx("/usr/sbin/psrinfo");
        if($#psrinfo >= 0) {
            return $#psrinfo +1;
        }
    }
    if(-x "/usr/sbin/prtconf") {
        my @prtconf = ::qqx("/usr/sbin/prtconf | grep cpu..instance");
        if($#prtconf >= 0) {
            return $#prtconf +1;
        }
    }
    if(-x "/usr/sbin/prtconf") {
        my @prtconf = ::qqx("/usr/sbin/prtconf | grep cpu..instance");
        if($#prtconf >= 0) {
            return $#prtconf +1;
        }
    }
    return undef;
}

sub no_of_cores_solaris {
    # Returns:
    #   Number of CPU cores on Solaris
    #   undef if not Solaris
    if(-x "/usr/sbin/psrinfo") {
        my @psrinfo = ::qqx("/usr/sbin/psrinfo");
        if($#psrinfo >= 0) {
            return $#psrinfo +1;
        }
    }
    if(-x "/usr/sbin/prtconf") {
        my @prtconf = ::qqx("/usr/sbin/prtconf | grep cpu..instance");
        if($#prtconf >= 0) {
            return $#prtconf +1;
        }
    }
    return undef;
}

sub no_of_cpus_aix {
    # Returns:
    #   Number of physical CPUs on AIX
    #   undef if not AIX
    local $/ = "\n";
    my $no_of_cpus = 0;
    if(-x "/usr/sbin/lscfg") {
	open(my $in_fh, "-|", "/usr/sbin/lscfg -vs |grep proc | wc -l|tr -d ' '")
	    || return undef;
	$no_of_cpus = <$in_fh>;
	chomp ($no_of_cpus);
	close $in_fh;
    }
    return $no_of_cpus;
}

sub no_of_cores_aix {
    # Returns:
    #   Number of CPU cores on AIX
    #   undef if not AIX
    my $no_of_cores;
    if(-x "/usr/bin/vmstat") {
	open(my $in_fh, "-|", "/usr/bin/vmstat 1 1") || return undef;
	while(<$in_fh>) {
	    /lcpu=([0-9]*) / and $no_of_cores = $1;
	}
	close $in_fh;
    }
    return $no_of_cores;
}

sub no_of_cpus_hpux {
    # Returns:
    #   Number of physical CPUs on HP-UX
    #   undef if not HP-UX
    my $no_of_cpus =
        ::qqx(qq{ /usr/bin/mpsched -s 2>&1 | grep 'Locality Domain Count' | awk '{ print \$4 }'});
    return $no_of_cpus;
}

sub no_of_cores_hpux {
    # Returns:
    #   Number of CPU cores on HP-UX
    #   undef if not HP-UX
    my $no_of_cores =
        ::qqx(qq{ /usr/bin/mpsched -s 2>&1 | perl -ne '/Processor Count\\D+(\\d+)/ and print "\$1\n"'});
    return $no_of_cores;
}

sub no_of_cpus_qnx {
    # Returns:
    #   Number of physical CPUs on QNX
    #   undef if not QNX
    # BUG: It is not known how to calculate this.
    my $no_of_cpus = 0;
    return $no_of_cpus;
}

sub no_of_cores_qnx {
    # Returns:
    #   Number of CPU cores on QNX
    #   undef if not QNX
    # BUG: It is not known how to calculate this.
    my $no_of_cores = 0;
    return $no_of_cores;
}

sub no_of_cpus_openserver {
    # Returns:
    #   Number of physical CPUs on SCO OpenServer
    #   undef if not SCO OpenServer
    my $no_of_cpus = 0;
    if(-x "/usr/sbin/psrinfo") {
        my @psrinfo = ::qqx("/usr/sbin/psrinfo");
        if($#psrinfo >= 0) {
            return $#psrinfo +1;
        }
    }
    return $no_of_cpus;
}

sub no_of_cores_openserver {
    # Returns:
    #   Number of CPU cores on SCO OpenServer
    #   undef if not SCO OpenServer
    my $no_of_cores = 0;
    if(-x "/usr/sbin/psrinfo") {
        my @psrinfo = ::qqx("/usr/sbin/psrinfo");
        if($#psrinfo >= 0) {
            return $#psrinfo +1;
        }
    }
    return $no_of_cores;
}

sub no_of_cpus_irix {
    # Returns:
    #   Number of physical CPUs on IRIX
    #   undef if not IRIX
    my $no_of_cpus = ::qqx(qq{ hinv | grep HZ | grep Processor | awk '{print \$1}' });
    return $no_of_cpus;
}

sub no_of_cores_irix {
    # Returns:
    #   Number of CPU cores on IRIX
    #   undef if not IRIX
    my $no_of_cores = ::qqx(qq{ hinv | grep HZ | grep Processor | awk '{print \$1}' });
    return $no_of_cores;
}

sub no_of_cpus_tru64 {
    # Returns:
    #   Number of physical CPUs on Tru64
    #   undef if not Tru64
    my $no_of_cpus = ::qqx("sizer -pr");
    return $no_of_cpus;
}

sub no_of_cores_tru64 {
    # Returns:
    #   Number of CPU cores on Tru64
    #   undef if not Tru64
    my $no_of_cores = ::qqx("sizer -pr");
    return $no_of_cores;
}

sub sshcommand {
    my $self = shift;
    if (not defined $self->{'sshcommand'}) {
        $self->sshcommand_of_sshlogin();
    }
    return $self->{'sshcommand'};
}

sub serverlogin {
    my $self = shift;
    if (not defined $self->{'serverlogin'}) {
        $self->sshcommand_of_sshlogin();
    }
    return $self->{'serverlogin'};
}

sub sshcommand_of_sshlogin {
    # 'server' -> ('ssh -S /tmp/parallel-ssh-RANDOM/host-','server')
    # 'user@server' -> ('ssh','user@server')
    # 'myssh user@server' -> ('myssh','user@server')
    # 'myssh -l user server' -> ('myssh -l user','server')
    # '/usr/bin/myssh -l user server' -> ('/usr/bin/myssh -l user','server')
    # Returns:
    #   sshcommand - defaults to 'ssh'
    #   login@host
    my $self = shift;
    my ($sshcmd, $serverlogin);
    # If $opt::ssh is unset, use $PARALLEL_SSH or 'ssh'
    $opt::ssh ||= $ENV{'PARALLEL_SSH'} || "ssh";
    if($self->{'string'} =~ /(.+) (\S+)$/) {
        # Own ssh command
        $sshcmd = $1; $serverlogin = $2;
    } else {
        # Normal ssh
        if($opt::controlmaster) {
            # Use control_path to make ssh faster
            my $control_path = $self->control_path_dir()."/ssh-%r@%h:%p";
            $sshcmd = $opt::ssh." -S ".$control_path;
            $serverlogin = $self->{'string'};
            if(not $self->{'control_path'}{$control_path}++) {
                # Master is not running for this control_path
                # Start it
                my $pid = fork();
                if($pid) {
                    $Global::sshmaster{$pid} ||= 1;
                } else {
		    $SIG{'TERM'} = undef;
                    # Ignore the 'foo' being printed
                    open(STDOUT,">","/dev/null");
                    # STDERR >/dev/null to ignore
                    open(STDERR,">","/dev/null");
                    open(STDIN,"<","/dev/null");
                    # Run a sleep that outputs data, so it will discover
		    # if the ssh connection closes.
                    my $sleep = ::shell_quote_scalar
			('$|=1;while(1){sleep 1;print "foo\n"}');
                    my @master = ($opt::ssh, "-MTS",
				  $control_path, $serverlogin, "--", "perl", "-e",
				  $sleep);
                    exec(@master);
                }
            }
        } else {
            $sshcmd = $opt::ssh; $serverlogin = $self->{'string'};
        }
    }

    if($serverlogin =~ s/(\S+)\@(\S+)/$2/) {
	# convert user@server to '-l user server'
	# because lsh does not support user@server
	$sshcmd = $sshcmd." -l ".$1;
    }

    $self->{'sshcommand'} = $sshcmd;
    $self->{'serverlogin'} = $serverlogin;
}

sub control_path_dir {
    # Returns:
    #   path to directory
    my $self = shift;
    if(not defined $self->{'control_path_dir'}) {
        $self->{'control_path_dir'} =
	    # Use $ENV{'TMPDIR'} as that is typically not
	    # NFS mounted
	    File::Temp::tempdir($ENV{'TMPDIR'}
				. "/control_path_dir-XXXX",
				CLEANUP => 1);
    }
    return $self->{'control_path_dir'};
}

sub rsync_transfer_cmd {
    # Command to run to transfer a file
    # Input:
    #   $file = filename of file to transfer
    #   $workdir = destination dir
    # Returns:
    #   $cmd = rsync command to run to transfer $file ("" if unreadable)
    my $self = shift;
    my $file = shift;
    my $workdir = shift;
    if(not -r $file) {
	::warning($file. " is not readable and will not be transferred.");
	return "true";
    }
    my $rsync_destdir;
    my $relpath = ($file !~ m:^/:) || ($file =~ m:/\./:); # Is the path relative or /./?
    if($relpath) {
	$rsync_destdir = ::shell_quote_file($workdir);
    } else {
	# rsync /foo/bar /
	$rsync_destdir = "/";
    }
    $file = ::shell_quote_file($file);
    my $sshcmd = $self->sshcommand();
    my $rsync_opts = $ENV{'PARALLEL_RSYNC_OPTS'}.
	" -e".::shell_quote_scalar($sshcmd);
    my $serverlogin = $self->serverlogin();
    # Make dir if it does not exist
    return "$sshcmd $serverlogin -- mkdir -p $rsync_destdir && " .
	rsync()." $rsync_opts $file $serverlogin:$rsync_destdir";
}

sub cleanup_cmd {
    # Command to run to remove the remote file
    # Input:
    #   $file = filename to remove
    #   $workdir = destination dir
    # Returns:
    #   $cmd = ssh command to run to remove $file and empty parent dirs
    my $self = shift;
    my $file = shift;
    my $workdir = shift;
    my $f = $file;
    if($f =~ m:/\./:) {
	# foo/bar/./baz/quux => workdir/baz/quux
	# /foo/bar/./baz/quux => workdir/baz/quux
	$f =~ s:.*/\./:$workdir/:;
    } elsif($f =~ m:^[^/]:) {
	# foo/bar => workdir/foo/bar
	$f = $workdir."/".$f;
    }
    my @subdirs = split m:/:, ::dirname($f);
    my @rmdir;
    my $dir = "";
    for(@subdirs) {
	$dir .= $_."/";
	unshift @rmdir, ::shell_quote_file($dir);
    }
    my $rmdir = @rmdir ? "sh -c ".::shell_quote_scalar("rmdir @rmdir 2>/dev/null;") : "";
    if(defined $opt::workdir and $opt::workdir eq "...") {
	$rmdir .= ::shell_quote_scalar("rm -rf " . ::shell_quote_file($workdir).';');
    }

    $f = ::shell_quote_file($f);
    my $sshcmd = $self->sshcommand();
    my $serverlogin = $self->serverlogin();
    return "$sshcmd $serverlogin -- ".::shell_quote_scalar("rm -f $f; $rmdir");
}

{
    my $rsync;

    sub rsync {
	# rsync 3.1.x uses protocol 31 which is unsupported by 2.5.7.
	# If the version >= 3.1.0: downgrade to protocol 30
	if(not $rsync) {
	    my @out = `rsync --version`;
	    for (@out) {
		if(/version (\d+.\d+)(.\d+)?/) {
		    if($1 >= 3.1) {
			# Version 3.1.0 or later: Downgrade to protocol 30
			$rsync = "rsync --protocol 30";
		    } else {
			$rsync = "rsync";
		    }
		}
	    }
	    $rsync or ::die_bug("Cannot figure out version of rsync: @out");
	}
	return $rsync;
    }
}


package JobQueue;

sub new {
    my $class = shift;
    my $commandref = shift;
    my $read_from = shift;
    my $context_replace = shift;
    my $max_number_of_args = shift;
    my $transfer_files = shift;
    my $return_files = shift;
    my $commandlinequeue = CommandLineQueue->new
	($commandref, $read_from, $context_replace, $max_number_of_args,
	 $transfer_files, $return_files);
    my @unget = ();
    return bless {
        'unget' => \@unget,
        'commandlinequeue' => $commandlinequeue,
        'this_job_no' => 0,
        'total_jobs' => undef,
    }, ref($class) || $class;
}

sub get {
    my $self = shift;

    $self->{'this_job_no'}++;
    if(@{$self->{'unget'}}) {
        return shift @{$self->{'unget'}};
    } else {
        my $commandline = $self->{'commandlinequeue'}->get();
        if(defined $commandline) {
            return Job->new($commandline);
        } else {
	    $self->{'this_job_no'}--;
            return undef;
        }
    }
}

sub unget {
    my $self = shift;
    unshift @{$self->{'unget'}}, @_;
    $self->{'this_job_no'} -= @_;
}

sub empty {
    my $self = shift;
    my $empty = (not @{$self->{'unget'}})
	&& $self->{'commandlinequeue'}->empty();
    ::debug("run", "JobQueue->empty $empty ");
    return $empty;
}

sub total_jobs {
    my $self = shift;
    if(not defined $self->{'total_jobs'}) {
	if($opt::pipe and not $opt::tee) {
	    ::error("--pipe is incompatible with --eta/--bar/--shuf");
	    ::wait_and_exit(255);
	}
	if($opt::sqlworker) {
	    $self->{'total_jobs'} = $Global::sql->total_jobs();
	} else {
	    my $record;
	    my @arg_records;
	    my $record_queue = $self->{'commandlinequeue'}{'arg_queue'};
	    my $start = time;
	    while($record = $record_queue->get()) {
		push @arg_records, $record;
		if(time - $start > 10) {
		    ::warning("Reading ".scalar(@arg_records).
			      " arguments took longer than 10 seconds.");
		    $opt::eta && ::warning("Consider removing --eta.");
		    $opt::bar && ::warning("Consider removing --bar.");
		    $opt::shuf && ::warning("Consider removing --shuf.");
		    last;
		}
	    }
	    while($record = $record_queue->get()) {
		push @arg_records, $record;
	    }
	    if($opt::shuf) {
		my $i = @arg_records;
		while (--$i) {
		    my $j = int rand($i+1);
		    @arg_records[$i,$j] = @arg_records[$j,$i];
		}
	    }
	    $record_queue->unget(@arg_records);
	    $self->{'total_jobs'} =
		::ceil((1+$#arg_records+$self->{'this_job_no'})
		       / ::max($Global::max_number_of_args,1));
	    ::debug("init","Total jobs: ".$self->{'total_jobs'}.
		    " (".(1+$#arg_records)."+".$self->{'this_job_no'}.")\n");
	}
    }
    return $self->{'total_jobs'};
}

sub flush_total_jobs {
    # Unset total_jobs to force recomputing
    my $self = shift;
    $self->{'total_jobs'} = undef;
}

sub next_seq {
    my $self = shift;

    return $self->{'commandlinequeue'}->seq();
}

sub quote_args {
    my $self = shift;
    return $self->{'commandlinequeue'}->quote_args();
}


package Job;

sub new {
    my $class = shift;
    my $commandlineref = shift;
    return bless {
        'commandline' => $commandlineref, # CommandLine object
        'workdir' => undef, # --workdir
        # filehandle for stdin (used for --pipe)
	# filename for writing stdout to (used for --files)
        # remaining data not sent to stdin (used for --pipe)
	# tmpfiles to cleanup when job is done
	'unlink' => [],
	# amount of data sent via stdin (used for --pipe)
        'transfersize' => 0, # size of files using --transfer
        'returnsize' => 0, # size of files using --return
        'pid' => undef,
        # hash of { SSHLogins => number of times the command failed there }
        'failed' => undef,
        'sshlogin' => undef,
        # The commandline wrapped with rsync and ssh
        'sshlogin_wrap' => undef,
        'exitstatus' => undef,
        'exitsignal' => undef,
	# Timestamp for timeout if any
	'timeout' => undef,
	'virgin' => 1,
	# Output used for SQL and CSV-output
	'output' => { 1 => [], 2 => [] },
	'halfline' => [],
    }, ref($class) || $class;
}

sub replaced {
    my $self = shift;
    $self->{'commandline'} or ::die_bug("commandline empty");
    return $self->{'commandline'}->replaced();
}

sub seq {
    my $self = shift;
    return $self->{'commandline'}->seq();
}

sub set_seq {
    my $self = shift;
    return $self->{'commandline'}->set_seq(shift);
}

sub slot {
    my $self = shift;
    return $self->{'commandline'}->slot();
}

sub free_slot {
    my $self = shift;
    push @Global::slots, $self->slot();
}

{
    my($cattail);

    sub cattail {
	# Returns:
	#   $cattail = perl program for:
	#     cattail "decompress program" writerpid [file_to_decompress or stdin] [file_to_unlink]
	if(not $cattail) {
	    $cattail = q{
		# cat followed by tail (possibly with rm as soon at the file is opened)
		# If $writerpid dead: finish after this round
		use Fcntl;
		$|=1;

		my ($comfile, $cmd, $writerpid, $read_file, $unlink_file) = @ARGV;
		if($read_file) {
		    open(IN,"<",$read_file) || die("cattail: Cannot open $read_file");
		} else {
		    *IN = *STDIN;
		}
		while(! -s $comfile) {
		    # Writer has not opened the buffer file, so we cannot remove it yet
		    $sleep = ($sleep < 30) ? ($sleep * 1.001 + 0.01) : ($sleep);
		    usleep($sleep);
		}
		# The writer and we have both opened the file, so it is safe to unlink it
		unlink $unlink_file;
		unlink $comfile;

		my $first_round = 1;
		my $flags;
		fcntl(IN, F_GETFL, $flags) || die $!; # Get the current flags on the filehandle
		$flags |= O_NONBLOCK; # Add non-blocking to the flags
		fcntl(IN, F_SETFL, $flags) || die $!; # Set the flags on the filehandle

		while(1) {
		    # clear EOF
		    seek(IN,0,1);
		    my $writer_running = kill 0, $writerpid;
		    $read = sysread(IN,$buf,131072);
		    if($read) {
			if($first_round) {
			    # Only start the command if there any input to process
			    $first_round = 0;
			    open(OUT,"|-",$cmd) || die("cattail: Cannot run $cmd");
			}

			# Blocking print
			while($buf) {
			    my $bytes_written = syswrite(OUT,$buf);
			    # syswrite may be interrupted by SIGHUP
			    substr($buf,0,$bytes_written) = "";
			}
			# Something printed: Wait less next time
			$sleep /= 2;
		    } else {
			if(eof(IN) and not $writer_running) {
			    # Writer dead: There will never be sent more to the decompressor
			    close OUT;
			    exit;
			}
			# TODO This could probably be done more efficiently using select(2)
			# Nothing read: Wait longer before next read
			# Up to 100 milliseconds
			$sleep = ($sleep < 100) ? ($sleep * 1.001 + 0.01) : ($sleep);
			usleep($sleep);
		    }
		}

		sub usleep {
		    # Sleep this many milliseconds.
		    my $secs = shift;
		    select(undef, undef, undef, $secs/1000);
		}
	    };
	    $cattail =~ s/#.*//mg;
	    $cattail =~ s/\s+/ /g;
	}
	return $cattail;
    }
}

sub openoutputfiles {
    # Open files for STDOUT and STDERR
    # Set file handles in $self->fh
    my $self = shift;
    my ($outfhw, $errfhw, $outname, $errname);

    if($opt::linebuffer and not
       ($opt::keeporder or $opt::files or $opt::results or
	$opt::compress or $opt::compress_program or
	$opt::decompress_program)) {
	# Do not save to files: Use non-blocking pipe
	my ($outfhr, $errfhr);
	pipe($outfhr, $outfhw) || die;
	pipe($errfhr, $errfhw) || die;
	$self->set_fh(1,'w',$outfhw);
	$self->set_fh(2,'w',$errfhw);
	$self->set_fh(1,'r',$outfhr);
	$self->set_fh(2,'r',$errfhr);
	# Make it possible to read non-blocking from the pipe
	for my $fdno (1,2) {
	    ::set_fh_non_blocking($self->fh($fdno,'r'));
	}
	# Return immediately because we do not need setting filenames
	return;
    } elsif($opt::results and not $Global::csv) {
	my $out = $self->{'commandline'}->results_out();
	my $seqname;
	if($out eq $opt::results or $out =~ m:/$:) {
	    # $opt::results = simple string or ending in /
	    # => $out is a dir/
	    # prefix/name1/val1/name2/val2/seq
	    $seqname = $out."seq";
	    # prefix/name1/val1/name2/val2/stdout
	    $outname = $out."stdout";
	    # prefix/name1/val1/name2/val2/stderr
	    $errname = $out."stderr";
	} else {
	    # $opt::results = replacement string not ending in /
	    # => $out is a file
	    $outname = $out;
	    $errname = "$out.err";
	    $seqname = "$out.seq";
	}
	my $seqfhw;
	if(not open($seqfhw, "+>", $seqname)) {
	    ::error("Cannot write to `$seqname'.");
	    ::wait_and_exit(255);
	}
	print $seqfhw $self->seq();
	close $seqfhw;
	if(not open($outfhw, "+>", $outname)) {
	    ::error("Cannot write to `$outname'.");
	    ::wait_and_exit(255);
	}
	if(not open($errfhw, "+>", $errname)) {
	    ::error("Cannot write to `$errname'.");
	    ::wait_and_exit(255);
	}
	$self->set_fh(1,"unlink","");
	$self->set_fh(2,"unlink","");
	if($opt::sqlworker) {
	    # Save the filenames in SQL table
	    $Global::sql->update("SET Stdout = ?, Stderr = ? ".
				 "WHERE Seq = ". $self->seq(),
				 $outname, $errname);
	}
    } elsif(not $opt::ungroup) {
	# To group we create temporary files for STDOUT and STDERR
	# To avoid the cleanup unlink the files immediately (but keep them open)
	if($opt::files) {
	    ($outfhw, $outname) = ::tmpfile(SUFFIX => ".par");
	    ($errfhw, $errname) = ::tmpfile(SUFFIX => ".par");
	    # --files => only remove stderr
	    $self->set_fh(1,"unlink","");
	    $self->set_fh(2,"unlink",$errname);
	} else {
	    ($outfhw, $outname) = ::tmpfile(SUFFIX => ".par");
	    ($errfhw, $errname) = ::tmpfile(SUFFIX => ".par");
	    $self->set_fh(1,"unlink",$outname);
	    $self->set_fh(2,"unlink",$errname);
	}
    } else {
	# --ungroup
	open($outfhw,">&",$Global::fd{1}) || die;
	open($errfhw,">&",$Global::fd{2}) || die;
	# File name must be empty as it will otherwise be printed
	$outname = "";
	$errname = "";
	$self->set_fh(1,"unlink",$outname);
	$self->set_fh(2,"unlink",$errname);
    }
    # Set writing FD
    $self->set_fh(1,'w',$outfhw);
    $self->set_fh(2,'w',$errfhw);
    $self->set_fh(1,'name',$outname);
    $self->set_fh(2,'name',$errname);
    if($opt::compress) {
	$self->filter_through_compress();
    } elsif(not $opt::ungroup) {
	$self->grouped();
    }
    if($opt::linebuffer) {
	# Make it possible to read non-blocking from
	# the buffer files
	# Used for --linebuffer with -k, --files, --res, --compress*
	for my $fdno (1,2) {
	    ::set_fh_non_blocking($self->fh($fdno,'r'));
	}
    }
}

sub add_rm {
    # Files to remove when job is done
    my $self = shift;
    push @{$self->{'unlink'}}, @_;
}

sub get_rm {
    # Files to remove when job is done
    my $self = shift;
    return @{$self->{'unlink'}};
}

sub cleanup {
    # Remove files when job is done
    my $self = shift;
    unlink $self->get_rm();
    delete @Global::unlink{$self->get_rm()};
}

sub grouped {
    my $self = shift;
    # Set reading FD if using --group (--ungroup does not need)
    for my $fdno (1,2) {
	# Re-open the file for reading
	# so fdw can be closed seperately
	# and fdr can be seeked seperately (for --line-buffer)
	open(my $fdr,"<", $self->fh($fdno,'name')) ||
	    ::die_bug("fdr: Cannot open ".$self->fh($fdno,'name'));
	$self->set_fh($fdno,'r',$fdr);
	# Unlink if required
	$Global::debug or ::rm($self->fh($fdno,"unlink"));
    }
}

sub empty_input_wrapper {
    # If no input: exit(0)
    # If some input: Pass input as input to command on STDIN
    # This avoids starting the command if there is no input.
    # Input:
    #   $command = command to pipe data to
    # Returns:
    #   $wrapped_command = the wrapped command
    my $command = shift;
    my $script =
	::spacefree(0,q{
	    if(sysread(STDIN, $buf, 1)) {
		open($fh, "|-", @ARGV) || die;
		syswrite($fh, $buf);
		# Align up to 128k block
		if($read = sysread(STDIN, $buf, 131071)) {
		    syswrite($fh, $buf);
		}
		while($read = sysread(STDIN, $buf, 131072)) {
		    syswrite($fh, $buf);
		}
		close $fh;
		exit ($?&127 ? 128+($?&127) : 1+$?>>8)
	    }
		  });
    ::debug("run",'Empty wrap: perl -e '.::shell_quote_scalar($script)."\n");
    if($Global::cshell
       and
       length $command > 499) {
	# csh does not like words longer than 1000 (499 quoted)
	# $command = "perl -e '".base64_zip_eval()."' ".
	# join" ",string_zip_base64(
	#         'exec "'.::perl_quote_scalar($command).'"');
        return 'perl -e '.::shell_quote_scalar($script)." ".
	    base64_wrap("exec \"$Global::shell\",'-c',\"".
				   ::perl_quote_scalar($command).'"');
    } else {
	return 'perl -e '.::shell_quote_scalar($script)." ".
	    $Global::shell." -c ".::shell_quote_scalar($command);
    }
}

sub filter_through_compress {
    my $self = shift;
    # Send stdout to stdin for $opt::compress_program(1)
    # Send stderr to stdin for $opt::compress_program(2)
    # cattail get pid:  $pid = $self->fh($fdno,'rpid');
    my $cattail = cattail();

    for my $fdno (1,2) {
	# Make a communication file.
	my ($fh, $comfile) = ::tmpfile(SUFFIX => ".pac");
	close $fh;
	# Compressor: (echo > $comfile; compress pipe) > output
	# When the echo is written to $comfile,
	# it is known that output file is opened,
	# thus output file can then be removed by the decompressor.
        my $wpid = open(my $fdw,"|-", "(echo > $comfile; ".
			empty_input_wrapper($opt::compress_program).") >".
			$self->fh($fdno,'name')) || die $?;
	$self->set_fh($fdno,'w',$fdw);
	$self->set_fh($fdno,'wpid',$wpid);
	# Decompressor: open output; -s $comfile > 0: rm $comfile output;
	#               decompress output > stdout
	my $rpid = open(my $fdr, "-|", "perl", "-e", $cattail, $comfile,
			$opt::decompress_program, $wpid,
			$self->fh($fdno,'name'),$self->fh($fdno,'unlink'))
	    || die $?;
	$self->set_fh($fdno,'r',$fdr);
	$self->set_fh($fdno,'rpid',$rpid);
    }
}



sub set_fh {
    # Set file handle
    my ($self, $fd_no, $key, $fh) = @_;
    $self->{'fd'}{$fd_no,$key} = $fh;
}

sub fh {
    # Get file handle
    my ($self, $fd_no, $key) = @_;
    return $self->{'fd'}{$fd_no,$key};
}

sub write {
    my $self = shift;
    my $remaining_ref = shift;
    my $stdin_fh = $self->fh(0,"w");

    my $len = length $$remaining_ref;
    # syswrite may not write all in one go,
    # so make sure everything is written.
    my $written;

    # If writing is to a closed pipe:
    #   Do not call signal handler, but let nothing be written
    local $SIG{PIPE} = undef;
    while($written = syswrite($stdin_fh,$$remaining_ref)){
	substr($$remaining_ref,0,$written) = "";
    }
}

sub set_block {
    # Copy stdin buffer from $block_ref up to $endpos
    # Prepend with $header_ref if virgin (i.e. not --roundrobin)
    # Remove $recstart and $recend if needed
    # Input:
    #   $header_ref = ref to $header to prepend
    #   $buffer_ref = ref to $buffer containing the block
    #   $endpos = length of $block to pass on
    #   $recstart = --recstart regexp
    #   $recend = --recend regexp
    # Returns:
    #   N/A
    my $self = shift;
    my ($header_ref,$buffer_ref,$endpos,$recstart,$recend) = @_;
    $self->{'block'} = ($self->virgin() ? $$header_ref : "").
	substr($$buffer_ref,0,$endpos);
    if($opt::remove_rec_sep) {
	remove_rec_sep(\$self->{'block'},$recstart,$recend);
    }
    $self->{'block_length'} = length $self->{'block'};
    $self->{'block_pos'} = 0;
    $self->add_transfersize($self->{'block_length'});
}

sub block_ref {
    my $self = shift;
    return \$self->{'block'};
}


sub block_length {
    my $self = shift;
    return $self->{'block_length'};
}

sub remove_rec_sep {
    my ($block_ref,$recstart,$recend) = @_;
    # Remove record separator
    $$block_ref =~ s/$recend$recstart//gos;
    $$block_ref =~ s/^$recstart//os;
    $$block_ref =~ s/$recend$//os;
}

sub non_blocking_write {
    my $self = shift;
    my $something_written = 0;
    use POSIX qw(:errno_h);

    my $in = $self->fh(0,"w");
    my $rv = syswrite($in,
		      substr($self->{'block'},$self->{'block_pos'}));
    if (!defined($rv) && $! == EAGAIN) {
	# would block - but would have written
	$something_written = 0;
	# avoid triggering auto expanding block
	$Global::no_autoexpand_block ||= 1;
    } elsif ($self->{'block_pos'}+$rv != $self->{'block_length'}) {
	# incomplete write
	# Remove the written part
	$self->{'block_pos'} += $rv;
	$something_written = $rv;
    } else {
	# successfully wrote everything
	# Empty block to free memory
	my $a = "";
	$self->set_block(\$a,\$a,0,"","");
	$something_written = $rv;
    }
    ::debug("pipe", "Non-block: ", $something_written);
    return $something_written;
}


sub virgin {
    my $self = shift;
    return $self->{'virgin'};
}

sub set_virgin {
    my $self = shift;
    $self->{'virgin'} = shift;
}

sub pid {
    my $self = shift;
    return $self->{'pid'};
}

sub set_pid {
    my $self = shift;
    $self->{'pid'} = shift;
}

sub starttime {
    # Returns:
    #   UNIX-timestamp this job started
    my $self = shift;
    return sprintf("%.3f",$self->{'starttime'});
}

sub set_starttime {
    my $self = shift;
    my $starttime = shift || ::now();
    $self->{'starttime'} = $starttime;
    $opt::sqlworker and
	$Global::sql->update("SET Starttime = ? WHERE Seq = ".$self->seq(),
			     $starttime);
}

sub runtime {
    # Returns:
    #   Run time in seconds with 3 decimals
    my $self = shift;
    return sprintf("%.3f",
		   int(($self->endtime() - $self->starttime())*1000)/1000);
}

sub endtime {
    # Returns:
    #   UNIX-timestamp this job ended
    #   0 if not ended yet
    my $self = shift;
    return ($self->{'endtime'} || 0);
}

sub set_endtime {
    my $self = shift;
    my $endtime = shift;
    $self->{'endtime'} = $endtime;
    $opt::sqlworker and
	$Global::sql->update("SET JobRuntime = ? WHERE Seq = ".$self->seq(),
			     $self->runtime());
}

sub is_timedout {
    # Is the job timedout?
    # Input:
    #   $delta_time = time that the job may run
    # Returns:
    #   True or false
    my $self = shift;
    my $delta_time = shift;
    return time > $self->{'starttime'} + $delta_time;
}

sub kill {
    my $self = shift;
    $self->set_exitstatus(-1);
    ::kill_sleep_seq($self->pid());
}

sub failed {
    # return number of times failed for this $sshlogin
    # Input:
    #   $sshlogin
    # Returns:
    #   Number of times failed for $sshlogin
    my $self = shift;
    my $sshlogin = shift;
    return $self->{'failed'}{$sshlogin};
}

sub failed_here {
    # return number of times failed for the current $sshlogin
    # Returns:
    #   Number of times failed for this sshlogin
    my $self = shift;
    return $self->{'failed'}{$self->sshlogin()};
}

sub add_failed {
    # increase the number of times failed for this $sshlogin
    my $self = shift;
    my $sshlogin = shift;
    $self->{'failed'}{$sshlogin}++;
}

sub add_failed_here {
    # increase the number of times failed for the current $sshlogin
    my $self = shift;
    $self->{'failed'}{$self->sshlogin()}++;
}

sub reset_failed {
    # increase the number of times failed for this $sshlogin
    my $self = shift;
    my $sshlogin = shift;
    delete $self->{'failed'}{$sshlogin};
}

sub reset_failed_here {
    # increase the number of times failed for this $sshlogin
    my $self = shift;
    delete $self->{'failed'}{$self->sshlogin()};
}

sub min_failed {
    # Returns:
    #   the number of sshlogins this command has failed on
    #   the minimal number of times this command has failed
    my $self = shift;
    my $min_failures =
	::min(map { $self->{'failed'}{$_} } keys %{$self->{'failed'}});
    my $number_of_sshlogins_failed_on = scalar keys %{$self->{'failed'}};
    return ($number_of_sshlogins_failed_on,$min_failures);
}

sub total_failed {
    # Returns:
    #   $total_failures = the number of times this command has failed
    my $self = shift;
    my $total_failures = 0;
    for (values %{$self->{'failed'}}) {
	$total_failures += $_;
    }
    return $total_failures;
}

{
    my $script;

    sub postpone_exit_and_cleanup {
	# Command to remove files and dirs (given as args) without
	# affecting the exit value in $?/$status.
	if(not $script) {
	    $script = "perl -e '".
		::spacefree(0,q{
		    $bash=shift;
		    $csh=shift;
		    for(@ARGV){
			unlink;
			rmdir;
		    }
		    if($bash=~s/h//) {
			exit $bash;
		    }
		    exit $csh;
			    }).
			"' ".'"$?h" "$status" ';
	}
	return $script
    }
}

{
    my $script;

    sub fifo_wrap {
	# Script to create a fifo, run a command on the fifo
	# while copying STDIN to the fifo, and finally
	# remove the fifo and return the exit code of the command.
	if(not $script) {
	    # {} == $PARALLEL_TMP for --fifo
	    # To make it csh compatible a wrapper needs to:
	    # * mkfifo
	    # * spawn $command &
	    # * cat > fifo
	    # * waitpid to get the exit code from $command
	    # * be less than 1000 chars long
	    $script = "perl -e '".
		(::spacefree
		 (0, q{
		     ($s,$c,$f) = @ARGV;
		     # mkfifo $PARALLEL_TMP
		     system "mkfifo", $f;
		     # spawn $shell -c $command &
		     $pid = fork || exec $s, "-c", $c;
		     open($o,">",$f) || die $!;
		     # cat > $PARALLEL_TMP
		     while(sysread(STDIN,$buf,131072)){
			 syswrite $o, $buf;
		     }
		     close $o;
		     # waitpid to get the exit code from $command
		     waitpid $pid,0;
		     # Cleanup
		     unlink $f;
		     exit $?/256;
		  }))."'";
	}
	return $script;
    }
}

sub wrapped {
    # Wrap command with:
    # * --shellquote
    # * --nice
    # * --cat
    # * --fifo
    # * --sshlogin
    # * --pipepart (@Global::cat_prepends)
    # * --tee (@Global::cat_prepends)
    # * --pipe
    # * --tmux
    # The ordering of the wrapping is important:
    # * --nice/--cat/--fifo should be done on the remote machine
    # * --pipepart/--pipe should be done on the local machine inside --tmux
    # Uses:
    #   $opt::shellquote
    #   $opt::nice
    #   $Global::shell
    #   $opt::cat
    #   $opt::fifo
    #   @Global::cat_prepends
    #   $opt::pipe
    #   $opt::tmux
    # Returns:
    #   $self->{'wrapped'} = the command wrapped with the above
    my $self = shift;
    if(not defined $self->{'wrapped'}) {
	my $command = $self->replaced();
	if($opt::shellquote) {
	    # Prepend /bin/echo (echo no-/bin is wrong in csh)
	    # and quote twice
	    $command = "/bin/echo " .
		::shell_quote_scalar(::shell_quote_scalar($command));
	}
	if($ENV{'PARALLEL_ENV'}) {
	    if(-e $ENV{'PARALLEL_ENV'}) {
		# This is a file/fifo: Replace envvar with content of file
		open(my $parallel_env, "<", $ENV{'PARALLEL_ENV'}) ||
		    ::die_bug("Cannot read parallel_env from $ENV{'PARALLEL_ENV'}");
		local $/;
		$ENV{'PARALLEL_ENV'} = <$parallel_env>;
		close $parallel_env;
	    }
	    # If $PARALLEL_ENV set, put that in front of the command
	    # Used for env_parallel.*
	    # Map \001 to \n to make it easer to quote \n in $PARALLEL_ENV
	    $ENV{'PARALLEL_ENV'} =~ s/\001/\n/g;
	    if($Global::shell =~ /zsh/) {
		# The extra 'eval' will make aliases work, too
		$command = $ENV{'PARALLEL_ENV'}."\n".
		    "eval ".::shell_quote_scalar($command);
	    } else {
		$command = $ENV{'PARALLEL_ENV'}."\n".$command;
	    }
	}
	if($opt::cat) {
	    # In '--cat' and '--fifo' {} == $PARALLEL_TMP.
	    # This is to make it possible to compute $PARALLEL_TMP on
	    # the fly when running remotely.
	    # $ENV{PARALLEL_TMP} is set in the remote wrapper before
	    # the command is run.
	    #
	    # Prepend 'cat > $PARALLEL_TMP;'
	    # Append 'unlink $PARALLEL_TMP without affecting $?'
	    $command =
		'cat > $PARALLEL_TMP;'.
		$command.";". postpone_exit_and_cleanup().
		'$PARALLEL_TMP';
	} elsif($opt::fifo) {
	    # Prepend fifo-wrapper. In essence:
	    #   mkfifo {}
	    #   ( $command ) &
	    #   # $command must read {}, otherwise this 'cat' will block
	    #   cat > {};
	    #   wait; rm {}
	    # without affecting $?
	    $command = fifo_wrap(). " ".
		$Global::shell. " ".
		::shell_quote_scalar($command).
		' $PARALLEL_TMP'.
		';';
	}
	# Wrap with ssh + tranferring of files
	$command = $self->sshlogin_wrap($command);
	if(@Global::cat_prepends) {
	    # --pipepart: prepend:
	    # < /tmp/foo perl -e 'while(@ARGV) {
	    #   sysseek(STDIN,shift,0) || die; $left = shift;
	    #   while($read = sysread(STDIN,$buf, ($left > 131072 ? 131072 : $left))){
	    #     $left -= $read; syswrite(STDOUT,$buf);
	    #   }
	    # }'  0 0 0 11 |
	    #
	    # --pipepart --tee: prepend:
	    #   cat dash-a-file |
	    #
	    # --pipe --tee: prepend:
	    #   cat fifo |
	    $command = (shift @Global::cat_prepends). " | ($command)";
	} elsif($opt::pipe) {
	    # Wrap with EOF-detector to avoid starting $command if EOF.
	    $command = empty_input_wrapper($command);
	}
	if($opt::tmux) {
	    # Wrap command with 'tmux'
	    $command = $self->tmux_wrap($command);
	}
	if($Global::cshell
	   and
	   length $command > 499) {
	    # csh does not like words longer than 1000 (499 quoted)
	    # $command = "perl -e '".base64_zip_eval()."' ".
	    # join" ",string_zip_base64(
	    #         'exec "'.::perl_quote_scalar($command).'"');
	    $command = base64_wrap("exec \"$Global::shell\",'-c',\"".
				   ::perl_quote_scalar($command).'"');
	}
	$self->{'wrapped'} = $command;
    }
    return $self->{'wrapped'};
}

sub set_sshlogin {
    my $self = shift;
    my $sshlogin = shift;
    $self->{'sshlogin'} = $sshlogin;
    delete $self->{'sshlogin_wrap'}; # If sshlogin is changed the wrap is wrong
    delete $self->{'wrapped'};

    if($opt::sqlworker) {
	# Identify worker as --sqlworker often runs on different machines
	my $host = $sshlogin->string();
	if($host eq ":") {
	    $host = ::hostname();
	}
	$Global::sql->update("SET Host = ? WHERE Seq = ".$self->seq(), $host);
    }
}

sub sshlogin {
    my $self = shift;
    return $self->{'sshlogin'};
}

sub string_base64 {
    # Base64 encode strings into 1000 byte blocks.
    # 1000 bytes is the largest word size csh supports
    # Input:
    #   @strings = to be encoded
    # Returns:
    #   @base64 = 1000 byte block
    $Global::use{"MIME::Base64"} ||= eval "use MIME::Base64; 1;";
    my @base64 = unpack("(A1000)*",encode_base64((join"",@_),""));
    return @base64;
}

sub string_zip_base64 {
    # Pipe string through 'bzip2 -9' and base64 encode it into 1000
    # byte blocks.
    # 1000 bytes is the largest word size csh supports
    # Zipping will make exporting big environments work, too
    # Input:
    #   @strings = to be encoded
    # Returns:
    #   @base64 = 1000 byte block
    my($zipin_fh, $zipout_fh,@base64);
    ::open3($zipin_fh,$zipout_fh,">&STDERR","bzip2 -9");
    if(fork) {
	close $zipin_fh;
	$Global::use{"MIME::Base64"} ||= eval "use MIME::Base64; 1;";
	# Split base64 encoded into 1000 byte blocks
	@base64 = unpack("(A1000)*",encode_base64((join"",<$zipout_fh>),""));
	close $zipout_fh;
    } else {
	close $zipout_fh;
	print $zipin_fh @_;
	close $zipin_fh;
	exit;
    }
    ::debug("base64","Orig:@_\nAs bzip2 base64:@base64\n");
    return @base64;
}

sub base64_zip_eval {
    # Script that:
    #   * reads base64 strings from @ARGV
    #   * decodes them
    #   * pipes through 'bzip2 -dc'
    #   * evals the result
    # Reverse of string_zip_base64 + eval
    # Will be wrapped in ' so single quote is forbidden
    # Returns:
    #   $script = 1-liner for perl -e
    my $script = ::spacefree(0,q{
        @GNU_Parallel = split /_/, "use_IPC::Open3;_use_MIME::Base64";
        eval"@GNU_Parallel";
        $chld = $SIG{CHLD};
	$SIG{CHLD} = "IGNORE";
	# Search for bzip2. Not found => use default path
	my $zip = (grep { -x $_ } "/usr/local/bin/bzip2")[0] || "bzip2";
	# $in = stdin on $zip, $out = stdout from $zip
	# Forget my() to save chars for csh
	# my($in, $out,$eval);
	open3($in,$out,">&STDERR",$zip,"-dc");
	if(my $perlpid = fork) {
	    close $in;
	    $eval = join "", <$out>;
	    close $out;
	} else {
	    close $out;
	    # Pipe decoded base64 into 'bzip2 -dc'
	    print $in (decode_base64(join"",@ARGV));
	    close $in;
	    exit;
	}
	wait;
	$SIG{CHLD} = $chld;
	eval $eval;
			     });
    ::debug("base64",$script,"\n");
    return $script;
}

sub base64_wrap {
    # base64 encode Perl code
    # Split it into chunks of < 1000 bytes
    # Prepend it with a decoder that eval's it
    # Input:
    #   $eval_string = Perl code to run
    # Returns:
    #   $shell_command = shell command that runs $eval_string
    my $eval_string = shift;
    return
	"perl -e ".
	::shell_quote_scalar(base64_zip_eval())." ".
	join" ",::shell_quote(string_zip_base64($eval_string));
}

sub base64_eval {
    # Script that:
    #   * reads base64 strings from @ARGV
    #   * decodes them
    #   * evals the result
    # Reverse of string_base64 + eval
    # Will be wrapped in ' so single quote is forbidden.
    # Spaces are stripped so spaces cannot be significant.
    # The funny 'use IPC::Open3'-syntax is to avoid spaces and
    # to make it clear that this is a GNU Parallel command
    # when looking at the process table.
    # Returns:
    #   $script = 1-liner for perl -e
    my $script = ::spacefree(0,q{
        @GNU_Parallel=("use","IPC::Open3;","use","MIME::Base64");
        eval "@GNU_Parallel";
        my $eval = decode_base64(join"",@ARGV);
	eval $eval;
			     });
    ::debug("base64",$script,"\n");
    return $script;
}

sub sshlogin_wrap {
    # Wrap the command with the commands needed to run remotely
    # Input:
    #   $command = command to run
    # Returns:
    #   $self->{'sshlogin_wrap'} = command wrapped with ssh+transfer commands
    sub monitor_parent_sshd_script {
	# This script is to solve the problem of
	# * not mixing STDERR and STDOUT
	# * terminating with ctrl-c
	# If its parent is ssh: all good
	# If its parent is init(1): ssh died, so kill children
	my $monitor_parent_sshd_script;

	if(not $monitor_parent_sshd_script) {
	    $monitor_parent_sshd_script =
		# This will be packed in ', so only use "
		::spacefree(0,'$shell = "'.($ENV{'PARALLEL_SHELL'} || '$ENV{SHELL}').'";'.
			    '$tmpdir = "'.::perl_quote_scalar($ENV{'TMPDIR'}).'";'.
			    '$nice = '.$opt::nice.';'.
			    q{
		# Set $PARALLEL_TMP to a non-existent file name in $TMPDIR
		do {
		    $ENV{PARALLEL_TMP} = $tmpdir."/par".
			join"", map { (0..9,"a".."z","A".."Z")[rand(62)] } (1..5);
		} while(-e $ENV{PARALLEL_TMP});
                $SIG{CHLD} = sub { $done = 1; };
		$pid = fork;
                unless($pid) {
		    # Make own process group to be able to kill HUP it later
		    eval { setpgrp };
		    eval { setpriority(0,0,$nice) };
		    exec $shell, "-c", ($bashfunc."@ARGV");
		    die "exec: $!\n";
		}
		do {
		    # Parent is not init (ppid=1), so sshd is alive
		    # Exponential sleep up to 1 sec
                    $s = $s < 1 ? 0.001 + $s * 1.03 : $s;
                    select(undef, undef, undef, $s);
                } until ($done || getppid == 1);
		# Kill HUP the process group if job not done
		kill(SIGHUP, -${pid}) unless $done;
		wait;
		exit ($?&127 ? 128+($?&127) : 1+$?>>8)
            });
	}
	return $monitor_parent_sshd_script;
    }

    sub vars_to_export {
	# Uses:
	#   @opt::env
	my @vars = ("parallel_bash_environment");
	for my $varstring (@opt::env) {
	    # Split up --env VAR1,VAR2
	    push @vars, split /,/, $varstring;
	}
	for (@vars) {
	    if(-r $_ and not -d) {
		# Read as environment definition bug #44041
		# TODO parse this
		my $fh = ::open_or_exit($_);
		$Global::envdef = join("",<$fh>);
		close $fh;
	    }
	}
	if(grep { /^_$/ } @vars) {
	    local $/ = "\n";
	    # --env _
	    # Include all vars that are not in a clean environment
	    if(open(my $vars_fh, "<", $Global::config_dir . "/ignored_vars")) {
		my @ignore = <$vars_fh>;
		chomp @ignore;
		my %ignore;
		@ignore{@ignore} = @ignore;
		close $vars_fh;
		push @vars, grep { not defined $ignore{$_} } keys %ENV;
		@vars = grep { not /^_$/ } @vars;
	    } else {
		::error("Run '$Global::progname --record-env' ".
			"in a clean environment first.");
		::wait_and_exit(255);
	    }
	}
	# Duplicate vars as BASH functions to include post-shellshock functions (v1+v2)
	# So --env myfunc should look for BASH_FUNC_myfunc() and BASH_FUNC_myfunc%%
	push(@vars, "PARALLEL_PID", "PARALLEL_SEQ",
	     map { ("BASH_FUNC_$_()", "BASH_FUNC_$_%%") } @vars);
	# Keep only defined variables
	return grep { defined($ENV{$_}) } @vars;
    }

    sub env_as_eval {
	# Returns:
	#   $eval = '$ENV{"..."}=...; ...'
	my @vars = vars_to_export();
	my $csh_friendly = not grep { /\n/ } @ENV{@vars};
	my @bash_functions = grep { substr($ENV{$_},0,4) eq "() {" } @vars;
	my @non_functions = (grep { !/PARALLEL_ENV/ }
			     grep { substr($ENV{$_},0,4) ne "() {" } @vars);

	# eval of @envset will set %ENV
	my $envset = join"", map {
	    '$ENV{"'.::perl_quote_scalar($_).'"}="'.
		::perl_quote_scalar($ENV{$_}).'";'; } @non_functions;

	# running @bashfunc on the command line, will set the functions
	my @bashfunc = map {
	    my $v=$_;
	    s/BASH_FUNC_(.*)(\(\)|%%)/$1/;
	    "$_$ENV{$v};export -f $_ >/dev/null;" } @bash_functions;
	# eval $bashfuncset will set $bashfunc
	my $bashfuncset;
	if(@bashfunc) {
	    # Functions are not supported for all shells
	    if($Global::shell !~ m:(bash|rbash|zsh|rzsh|dash|ksh):) {
		::warning("Shell functions may not be supported in $Global::shell.");
	    }
	    $bashfuncset =
		'@bash_functions=qw('."@bash_functions".");".
		::spacefree(1,'$shell="'.($ENV{'PARALLEL_SHELL'} || '$ENV{SHELL}').'";'.q{
		    if($shell=~/csh/) {
			print STDERR "CSH/TCSH DO NOT SUPPORT newlines IN VARIABLES/FUNCTIONS. Unset @bash_functions\n";
			exec "false";
		    }
			    }).
				"\n".'$bashfunc = "'.::perl_quote_scalar("@bashfunc").'";';
	} else {
	    $bashfuncset = '$bashfunc = "";'
	}
	if($ENV{"parallel_bash_environment"}) {
	    $bashfuncset .= '$bashfunc .= "eval\ \"\$parallel_bash_environment\"\;";';
	}
	::debug("base64",$envset,$bashfuncset,"\n");
	return $csh_friendly,$envset,$bashfuncset;
    }

    my $self = shift;
    my $command = shift;
    # TODO test that *sh -c 'parallel --env' use *sh
    if(not defined $self->{'sshlogin_wrap'}) {
	my $sshlogin = $self->sshlogin();
	my $serverlogin = $sshlogin->serverlogin();
	my $quoted_remote_command;
	$ENV{'PARALLEL_SEQ'} = $self->seq();
	$ENV{'PARALLEL_PID'} = $$;
	if($serverlogin eq ":") {
	    if($opt::workdir) {
		# Create workdir if needed. Then cd to it.
	        my $wd = $self->workdir();
		if($opt::workdir eq "." or $opt::workdir eq "...") {
		    # If $wd does not start with '/': Prepend $HOME
		    $wd =~ s:^([^/]):$ENV{'HOME'}/$1:;
		}
		::mkdir_or_die($wd);
		$command = "cd ".::shell_quote_scalar($wd)." || exit 255; ".$command;
	    }
	    if(@opt::env) {
		# Prepend with environment setter, which sets functions in zsh
		my ($csh_friendly,$envset,$bashfuncset) = env_as_eval();
		my $perl_code = $envset.$bashfuncset.
		    '@ARGV="'.::perl_quote_scalar($command).'";'.
		    "exec\"$Global::shell\",\"-c\",\(\$bashfunc.\"\@ARGV\"\)\;die\"exec:\$\!\\n\"\;";
		if(length $perl_code > 999
		   or
		   not $csh_friendly
		   or
		   $command =~ /\n/) {
		    # csh does not deal well with > 1000 chars in one word
		    # csh does not deal well with $ENV with \n
		    $self->{'sshlogin_wrap'} = base64_wrap($perl_code);
		} else {
		    $self->{'sshlogin_wrap'} = "perl -e ".::shell_quote_scalar($perl_code);
		}
	    } else {
		$self->{'sshlogin_wrap'} = $command;
	    }
	} else {
	    my $pwd = "";
	    if($opt::workdir) {
		# Create remote workdir if needed. Then cd to it.
	        my $wd = $self->workdir();
		$pwd = qq{system("mkdir","-p","--","$wd"); chdir "$wd" ||}.
		    qq{print(STDERR "parallel: Cannot chdir to $wd\\n") && exit 255;};
	    }
	    my ($csh_friendly,$envset,$bashfuncset) = env_as_eval();
	    my $remote_command = $pwd.$envset.$bashfuncset.
		'@ARGV="'.::perl_quote_scalar($command).'";'.
		monitor_parent_sshd_script();
	    $quoted_remote_command = "perl -e ".
		::shell_quote_scalar($remote_command);
	    my $dq_remote_command =
		::shell_quote_scalar($quoted_remote_command);
	    if(length $dq_remote_command > 999
	       or
	       not $csh_friendly
	       or
	       $command =~ /\n/) {
		# csh does not deal well with > 1000 chars in one word
		# csh does not deal well with $ENV with \n
		$quoted_remote_command =
		    "perl -e ".
		    ::shell_quote_scalar(::shell_quote_scalar(base64_zip_eval()))." ".
		    join" ",::shell_quote(::shell_quote(string_zip_base64($remote_command)));
	    } else {
		$quoted_remote_command = $dq_remote_command;
	    }

	    my $sshcmd = $sshlogin->sshcommand();
	    my ($pre,$post,$cleanup)=("","","");
	    # --transfer
	    $pre .= $self->sshtransfer();
	    # --return
	    $post .= $self->sshreturn();
	    # --cleanup
	    $post .= $self->sshcleanup();
	    if($post) {
		# We need to save the exit status of the job
		$post = '_EXIT_status=$?; ' . $post . ' exit $_EXIT_status;';
	    }
	    $self->{'sshlogin_wrap'} =
		($pre
		 . "$sshcmd $serverlogin -- exec "
		 . $quoted_remote_command
		 . ";"
		 . $post);
	}
    }
    return $self->{'sshlogin_wrap'};
}

sub transfer {
    # Files to transfer
    # Non-quoted and with {...} substituted
    # Returns:
    #   @transfer - File names of files to transfer
    my $self = shift;

    my $transfersize = 0;
    my @transfer = $self->{'commandline'}->
	replace_placeholders($self->{'commandline'}{'transfer_files'},0,0);
    for(@transfer) {
	# filesize
	if(-e $_) {
	    $transfersize += (stat($_))[7];
	}
    }
    $self->add_transfersize($transfersize);
    return @transfer;
}

sub transfersize {
    my $self = shift;
    return $self->{'transfersize'};
}

sub add_transfersize {
    my $self = shift;
    my $transfersize = shift;
    $self->{'transfersize'} += $transfersize;
    $opt::sqlworker and
	$Global::sql->update("SET Send = ? WHERE Seq = ".$self->seq(),
			     $self->{'transfersize'});
}

sub sshtransfer {
    # Returns for each transfer file:
    #   rsync $file remote:$workdir
    my $self = shift;
    my @pre;
    my $sshlogin = $self->sshlogin();
    my $workdir = $self->workdir();
    for my $file ($self->transfer()) {
	push @pre, $sshlogin->rsync_transfer_cmd($file,$workdir).";";
    }
    return join("",@pre);
}

sub return {
    # Files to return
    # Non-quoted and with {...} substituted
    # Returns:
    #   @non_quoted_filenames
    my $self = shift;
    return $self->{'commandline'}->
	replace_placeholders($self->{'commandline'}{'return_files'},0,0);
}

sub returnsize {
    # This is called after the job has finished
    # Returns:
    #   $number_of_bytes transferred in return
    my $self = shift;
    for my $file ($self->return()) {
	if(-e $file) {
	    $self->{'returnsize'} += (stat($file))[7];
	}
    }
    return $self->{'returnsize'};
}

sub add_returnsize {
    my $self = shift;
    my $returnsize = shift;
    $self->{'returnsize'} += $returnsize;
    $opt::sqlworker and
	$Global::sql->update("SET Receive = ? WHERE Seq = ".$self->seq(),
			     $self->{'returnsize'});
}

sub sshreturn {
    # Returns for each return-file:
    #   rsync remote:$workdir/$file .
    my $self = shift;
    my $sshlogin = $self->sshlogin();
    my $sshcmd = $sshlogin->sshcommand();
    my $serverlogin = $sshlogin->serverlogin();
    my $rsync_opts = $ENV{'PARALLEL_RSYNC_OPTS'}.
	" -e".::shell_quote_scalar($sshcmd);
    my $pre = "";
    for my $file ($self->return()) {
	$file =~ s:^\./::g; # Remove ./ if any
	my $relpath = ($file !~ m:^/:) || ($file =~ m:/\./:); # Is the path relative or /./?
	my $cd = "";
	my $wd = "";
	if($relpath) {
	    #   rsync -avR /foo/./bar/baz.c remote:/tmp/
	    # == (on old systems)
	    #   rsync -avR --rsync-path="cd /foo; rsync" remote:bar/baz.c /tmp/
	    $wd = ::shell_quote_file($self->workdir()."/");
	}
	# Only load File::Basename if actually needed
	$Global::use{"File::Basename"} ||= eval "use File::Basename; 1;";
	# dir/./file means relative to dir, so remove dir on remote
	$file =~ m:(.*)/\./:;
	my $basedir = $1 ? ::shell_quote_file($1."/") : "";
	my $nobasedir = $file;
	$nobasedir =~ s:.*/\./::;
	$cd = ::shell_quote_file(::dirname($nobasedir));
	my $rsync_cd = '--rsync-path='.::shell_quote_scalar("cd $wd$cd; rsync");
	my $basename =
	    ::shell_quote_scalar(::shell_quote_file(::basename($file)));
	# --return
	#   mkdir -p /home/tange/dir/subdir/;
        #   rsync (--protocol 30) -rlDzR
	#     --rsync-path="cd /home/tange/dir/subdir/; rsync"
        #     server:file.gz /home/tange/dir/subdir/
	$pre .= "mkdir -p $basedir$cd && ". $sshlogin->rsync().
	    " $rsync_cd $rsync_opts $serverlogin:".
	     $basename . " ".$basedir.$cd.";";
    }
    return $pre;
}

sub sshcleanup {
    # Return the sshcommand needed to remove the file
    # Returns:
    #   ssh command needed to remove files from sshlogin
    my $self = shift;
    my $sshlogin = $self->sshlogin();
    my $sshcmd = $sshlogin->sshcommand();
    my $serverlogin = $sshlogin->serverlogin();
    my $workdir = $self->workdir();
    my $cleancmd = "";

    for my $file ($self->remote_cleanup()) {
	my @subworkdirs = parentdirs_of($file);
	$cleancmd .= $sshlogin->cleanup_cmd($file,$workdir).";";
    }
    if(defined $opt::workdir and $opt::workdir eq "...") {
	$cleancmd .= "$sshcmd $serverlogin -- rm -rf " . ::shell_quote_scalar($workdir).';';
    }
    return $cleancmd;
}

sub remote_cleanup {
    # Returns:
    #   Files to remove at cleanup
    my $self = shift;
    if($opt::cleanup) {
	my @transfer = $self->transfer();
	my @return = $self->return();
	return (@transfer,@return);
    } else {
	return ();
    }
}

sub workdir {
    # Returns:
    #   the workdir on a remote machine
    my $self = shift;
    if(not defined $self->{'workdir'}) {
	my $workdir;
	if(defined $opt::workdir) {
	    if($opt::workdir eq ".") {
		# . means current dir
		my $home = $ENV{'HOME'};
		eval 'use Cwd';
		my $cwd = cwd();
		$workdir = $cwd;
		if($home) {
		    # If homedir exists: remove the homedir from
		    # workdir if cwd starts with homedir
		    # E.g. /home/foo/my/dir => my/dir
		    # E.g. /tmp/my/dir => /tmp/my/dir
		    my ($home_dev, $home_ino) = (stat($home))[0,1];
		    my $parent = "";
		    my @dir_parts = split(m:/:,$cwd);
		    my $part;
		    while(defined ($part = shift @dir_parts)) {
			$part eq "" and next;
			$parent .= "/".$part;
			my ($parent_dev, $parent_ino) = (stat($parent))[0,1];
			if($parent_dev == $home_dev and $parent_ino == $home_ino) {
			    # dev and ino is the same: We found the homedir.
			    $workdir = join("/",@dir_parts);
			    last;
			}
		    }
		}
		if($workdir eq "") {
		    $workdir = ".";
		}
	    } elsif($opt::workdir eq "...") {
		$workdir = ".parallel/tmp/" . ::hostname() . "-" . $$
		    . "-" . $self->seq();
	    } else {
		$workdir = $self->{'commandline'}->
		    replace_placeholders([$opt::workdir],0,0);
		#$workdir = $opt::workdir;
		# Rsync treats /./ special. We dont want that
		$workdir =~ s:/\./:/:g; # Remove /./
		$workdir =~ s:(.)/+$:$1:; # Remove ending / if any
		$workdir =~ s:^\./::g; # Remove starting ./ if any
	    }
	} else {
	    $workdir = ".";
	}
	$self->{'workdir'} = ::shell_quote_scalar($workdir);
    }
    return $self->{'workdir'};
}

sub parentdirs_of {
    # Return:
    #   all parentdirs except . of this dir or file - sorted desc by length
    my $d = shift;
    my @parents = ();
    while($d =~ s:/[^/]+$::) {
	if($d ne ".") {
	    push @parents, $d;
	}
    }
    return @parents;
}

sub start {
    # Setup STDOUT and STDERR for a job and start it.
    # Returns:
    #   job-object or undef if job not to run

    sub open3_setpgrp_internal {
	# Run open3+setpgrp followed by the command
	# Input:
	#   $stdin_fh = Filehandle to use as STDIN
	#   $stdout_fh = Filehandle to use as STDOUT
	#   $stderr_fh = Filehandle to use as STDERR
	#   $command = Command to run
	# Returns:
	#   $pid = Process group of job started
	my ($stdin_fh,$stdout_fh,$stderr_fh,$command) = @_;
	my $pid;
	local (*OUT,*ERR);
	open OUT, '>&', $stdout_fh or ::die_bug("Can't dup STDOUT: $!");
	open ERR, '>&', $stderr_fh or ::die_bug("Can't dup STDERR: $!");
	# The eval is needed to catch exception from open3
	eval {
	    if(not $pid = ::open3($stdin_fh, ">&OUT", ">&ERR", "-")) {
		# Each child gets its own process group to make it safe to killall
		eval{setpgrp(0,0)};
		exec($Global::shell,"-c",$command)
		    || ::die_bug("open3-$stdin_fh $command");
	    }
	};
	return $pid;
    }

    sub open3_setpgrp_external {
	# Run open3 on $command wrapped with a perl script doing setpgrp
	# Works on systems that do not support open3(,,,"-")
	# Input:
	#   $stdin_fh = Filehandle to use as STDIN
	#   $stdout_fh = Filehandle to use as STDOUT
	#   $stderr_fh = Filehandle to use as STDERR
	#   $command = Command to run
	# Returns:
	#   $pid = Process group of job started
	my ($stdin_fh,$stdout_fh,$stderr_fh,$command) = @_;
	local (*OUT,*ERR);
	open OUT, '>&', $stdout_fh or ::die_bug("Can't dup STDOUT: $!");
	open ERR, '>&', $stderr_fh or ::die_bug("Can't dup STDERR: $!");

	my $pid;
	my @setpgrp_wrap =
	    ('perl','-e',
	     "eval\{setpgrp\}\;eval\{setpriority\(0,0,$opt::nice\)\}\;".
	     "exec '$Global::shell', '-c', \@ARGV");
	# The eval is needed to catch exception from open3
	eval {
	    $pid = ::open3($stdin_fh, ">&OUT", ">&ERR", @setpgrp_wrap, $command)
		|| ::die_bug("open3-$stdin_fh");
	    1;
	};
	return $pid;
    }

    sub open3_setpgrp {
	# Select and run open3_setpgrp_internal/open3_setpgrp_external
	no warnings 'redefine';
	my ($outfh,$name) = ::tmpfile(SUFFIX => ".tst");
	# Test to see if open3(x,x,x,"-") is fully supported
	# Can an exported bash function be called via open3?
	my $script = 'if($pid=::open3($i,$o,$e,"-")) { wait; } '.
	    'else { exec("bash","-c","testfun && true"); }';
	my $bash =
	    ::shell_quote_scalar_default(
	    "testfun() { rm $name; }; export -f testfun; ".
	    "perl -MIPC::Open3 -e ".
	    ::shell_quote_scalar_default($script)
	    );
	# Redirect STDERR temporarily,
	# so errors on MacOS X are ignored.
	open my $saveerr, ">&STDERR";
	open STDERR, '>', "/dev/null";
	# Run the test
	::debug("init",qq{bash -c $bash 2>/dev/null});
	qx{ bash -c $bash 2>/dev/null };
	open STDERR, ">&", $saveerr;

	if(-e $name) {
	    # Does not support open3(x,x,x,"-")
	    # or does not have bash:
	    # Use (slow) external version
	    unlink($name);
	    *open3_setpgrp = \&open3_setpgrp_external;
	    ::debug("init","open3_setpgrp_external chosen\n");
	} else {
	    # Supports open3(x,x,x,"-")
	    # This is 0.5 ms faster to run
	    *open3_setpgrp = \&open3_setpgrp_internal;
	    ::debug("init","open3_setpgrp_internal chosen\n");
	}
	# The sub is now redefined. Call it
	return open3_setpgrp(@_);
    }

    my $job = shift;
    # Get the shell command to be executed (possibly with ssh infront).
    my $command = $job->wrapped();
    my $pid;

    if($Global::interactive or $Global::stderr_verbose) {
	$job->interactive_start();
    }
    # Must be run after $job->interactive_start():
    # $job->interactive_start() may call $job->skip()
    if($job->{'commandline'}{'skip'}) {
	# $job->skip() was called
	$command = "true";
    }
    $job->openoutputfiles();
    # Call slot to store the slot value
    $job->slot();
    my($stdout_fh,$stderr_fh) = ($job->fh(1,"w"),$job->fh(2,"w"));
    if($opt::ungroup or $opt::sqlworker) {
	print_dryrun_and_verbose($stdout_fh,$job,$command);
    }
    if($opt::dryrun or $opt::sqlmaster) { $command = "true"; }
    $ENV{'PARALLEL_SEQ'} = $job->seq();
    $ENV{'PARALLEL_PID'} = $$;
    $ENV{'PARALLEL_TMP'} = ::tmpname("par");
    $job->add_rm($ENV{'PARALLEL_TMP'});
    ::debug("run", $Global::total_running, " processes . Starting (",
	    $job->seq(), "): $command\n");
    if($opt::pipe) {
	my ($stdin_fh) = ::gensym();
	$pid = open3_setpgrp($stdin_fh,$stdout_fh,$stderr_fh,$command);
	if($opt::roundrobin and not $opt::keeporder) {
	    # --keep-order will make sure the order will be reproducible
	    ::set_fh_non_blocking($stdin_fh);
	}
	$job->set_fh(0,"w",$stdin_fh);
    } elsif ($opt::tty and not $Global::tty_taken and -c "/dev/tty" and
	     open(my $devtty_fh, "<", "/dev/tty")) {
	# Give /dev/tty to the command if no one else is using it
	# The eval is needed to catch exception from open3
	local (*IN,*OUT,*ERR);
	open OUT, '>&', $stdout_fh or ::die_bug("Can't dup STDOUT: $!");
	open ERR, '>&', $stderr_fh or ::die_bug("Can't dup STDERR: $!");
	*IN = $devtty_fh;
	# The eval is needed to catch exception from open3
	my @wrap = ('perl','-e',
			    "eval\{setpriority\(0,0,$opt::nice\)\}\;".
			    "exec '$Global::shell', '-c', \@ARGV");
	eval {
	    $pid = ::open3("<&IN", ">&OUT", ">&ERR", @wrap, $command)
		|| ::die_bug("open3-/dev/tty");
	    1;
	};
	$Global::tty_taken = $pid;
	close $devtty_fh;
    } else {
	$pid = open3_setpgrp(::gensym(),$stdout_fh,$stderr_fh,$command);
    }
    if($pid) {
	# A job was started
	$Global::total_running++;
	$Global::total_started++;
	$job->set_pid($pid);
	$job->set_starttime();
	$Global::running{$job->pid()} = $job;
	if($opt::timeout) {
	    $Global::timeoutq->insert($job);
	}
	$Global::newest_job = $job;
	$Global::newest_starttime = ::now();
	return $job;
    } else {
	# No more processes
	::debug("run", "Cannot spawn more jobs.\n");
	return undef;
    }
}

sub interactive_start {
    my $self = shift;
    my $command = $self->wrapped();
    if($Global::interactive) {
	::status_no_nl("$command ?...");
	open(my $tty_fh, "<", "/dev/tty") || ::die_bug("interactive-tty");
	my $answer = <$tty_fh>;
	close $tty_fh;
	my $run_yes = ($answer =~ /^\s*y/i);
	if (not $run_yes) {
	    $self->{'commandline'}->skip();
	}
    } else {
	print $Global::original_stderr "$command\n";
    }
}

sub print_dryrun_and_verbose {
    # For $opt::ungroup we print these ASAP
    # For $opt::group they are part of print()
    my $stdout_fh = shift;
    my $job = shift;
    my $command = shift;
    if($opt::dryrun or $Global::verbose) {
	if($Global::verbose <= 1) {
	    print $stdout_fh $job->replaced(),"\n";
	} else {
	    # Verbose level > 1: Print the rsync and stuff
	    print $stdout_fh $command,"\n";
	}
    }
    if($opt::sqlworker) {
	$Global::sql->update("SET Command = ? WHERE Seq = ".$job->seq(),
			     $job->replaced());
    }
}

{
    my $tmuxsocket;

    sub tmux_wrap {
	# Wrap command with tmux for session pPID
	# Input:
	#   $actual_command = the actual command being run (incl ssh wrap)
	my $self = shift;
	my $actual_command = shift;
	# Temporary file name. Used for fifo to communicate exit val
	my $tmpfifo=::tmpname("tmx");
	$self->add_rm($tmpfifo);

	if(length($tmpfifo) >=100) {
	    ::error("tmux does not support sockets with path > 100.");
	    ::wait_and_exit(255);
	}
	if($opt::tmuxpane) {
	    # Move the command into a pane in window 0
	    $actual_command = $ENV{'PARALLEL_TMUX'}.' joinp -t :0 ; '.
		$ENV{'PARALLEL_TMUX'}.' select-layout -t :0 tiled ; '.
		$actual_command;
	}
	my $visual_command = $self->replaced();
	my $title = $visual_command;
	if($visual_command =~ /\0/) {
	    ::error("Command line contains NUL. tmux is confused by NUL.");
	    ::wait_and_exit(255);
	}
	# ; causes problems
	# ascii 194-245 annoys tmux
	$title =~ tr/[\011-\016;\302-\365]/ /s;
	$title = ::shell_quote_scalar($title);

	my $l_act = length($actual_command);
	my $l_tit = length($title);
	my $l_fifo = length($tmpfifo);
	# The line to run contains a 118 chars extra code + the title 2x
	my $l_tot = 2 * $l_tit + $l_act + $l_fifo;

	my $quoted_space75 = ::shell_quote_scalar(" ")x75;
	while($l_tit < 1000 and
	      (
	       (890 < $l_tot and $l_tot < 1350)
	       or
	       (9250 < $l_tot and $l_tot < 9800)
	      )) {
	    # tmux blocks for certain lengths:
	    # 900 < title + command < 1200
	    # 9250 < title + command < 9800
	    # but only if title < 1000, so expand the title with 75 spaces
	    # The measured lengths are:
	    # 996 < (title + whole command) < 1127
	    # 9331 < (title + whole command) < 9636
	    $title .= $quoted_space75;
	    $l_tit = length($title);
	    $l_tot = 2 * $l_tit + $l_act + $l_fifo;
	}

	my $tmux;
	$ENV{'PARALLEL_TMUX'} ||= "tmux";
	if(not $tmuxsocket) {
	    $tmuxsocket = ::tmpname("tms");
	    if($opt::fg) {
		if(not fork) {
		    # Run tmux in the foreground
		    # Wait for the socket to appear
		    while (not -e $tmuxsocket) { }
		    `$ENV{'PARALLEL_TMUX'} -S $tmuxsocket attach`;
		    exit;
		}
	    }
	    ::status("See output with: $ENV{'PARALLEL_TMUX'} -S $tmuxsocket attach");
	}
	$tmux = "sh -c '".
	    $ENV{'PARALLEL_TMUX'}." -S $tmuxsocket new-session -s p$$ -d \"sleep .2\" >/dev/null 2>&1';" .
	    $ENV{'PARALLEL_TMUX'}." -S $tmuxsocket new-window -t p$$ -n $title";

	::debug("tmux", "title len:", $l_tit, " act ", $l_act, " max ",
		$Limits::Command::line_max_len, " tot ",
		$l_tot, "\n");

	return "mkfifo $tmpfifo && $tmux ".
	    # Run in tmux
	    ::shell_quote_scalar
	    (
	     "(".$actual_command.');'.
	     # The triple print is needed - otherwise the testsuite fails
	     q[ perl -e 'while($t++<3){ print $ARGV[0],"\n" }' $?h/$status >> ].$tmpfifo."&".
	     "echo $title; echo \007Job finished at: `date`;sleep 10"
	    ).
	    # Run outside tmux
	    # Read a / separated line: 0h/2 for csh, 2/0 for bash.
	    # If csh the first will be 0h, so use the second as exit value.
	    # Otherwise just use the first value as exit value.
	    q{; exec perl -e '$/="/";$_=<>;$c=<>;unlink $ARGV; /(\d+)h/ and exit($1);exit$c' }.$tmpfifo;
    }
}

sub is_already_in_results {
    # Do we already have results for this job?
    # Returns:
    #   $job_already_run = bool whether there is output for this or not
    my $job = $_[0];
    my $out = $job->{'commandline'}->results_out();
    ::debug("run", "Test ${out}stdout", -e "${out}stdout", "\n");
    return(-e $out."stdout" or -f $out);
}

sub is_already_in_joblog {
    my $job = shift;
    return vec($Global::job_already_run,$job->seq(),1);
}

sub set_job_in_joblog {
    my $job = shift;
    vec($Global::job_already_run,$job->seq(),1) = 1;
}

sub should_be_retried {
    # Should this job be retried?
    # Returns
    #   0 - do not retry
    #   1 - job queued for retry
    my $self = shift;
    if (not $opt::retries) {
	return 0;
    }
    if(not $self->exitstatus() and not $self->exitsignal()) {
	# Completed with success. If there is a recorded failure: forget it
	$self->reset_failed_here();
	return 0;
    } else {
	# The job failed. Should it be retried?
	$self->add_failed_here();
	my $retries = $self->{'commandline'}->
	    replace_placeholders([$opt::retries],0,0);
	if($self->total_failed() == $retries) {
	    # This has been retried enough
	    return 0;
	} else {
	    # This command should be retried
	    $self->set_endtime(undef);
	    $self->reset_exitstatus();
	    $Global::JobQueue->unget($self);
	    ::debug("run", "Retry ", $self->seq(), "\n");
	    return 1;
	}
    }
}

{
    my (%print_later,$job_seq_to_print);

    sub print_earlier_jobs {
	# Print jobs whose output is postponed due to --keep-order
	# Returns: N/A
	my $job = shift;
	$print_later{$job->seq()} = $job;
	$job_seq_to_print ||= 1;
	my $returnsize = 0;
	::debug("run", "Looking for: $job_seq_to_print ",
		"This: ", $job->seq(), "\n");
	for(;vec($Global::job_already_run,$job_seq_to_print,1);
	    $job_seq_to_print++) {}
	while(my $j = $print_later{$job_seq_to_print}) {
	    $returnsize += $j->print();
	    if($j->endtime()) {
		# Job finished - look at the next
		delete $print_later{$job_seq_to_print};
		$job_seq_to_print++;
		next;
	    } else {
		# Job not finished yet - look at it again next round
		last;
	    }
	}
	return $returnsize;
    }
}

sub print {
    # Print the output of the jobs
    # Returns: N/A

    my $self = shift;
    ::debug("print", ">>joboutput ", $self->replaced(), "\n");
    if($opt::dryrun) {
	# Nothing was printed to this job:
	# cleanup tmp files if --files was set
	::rm($self->fh(1,"name"));
    }
    if($opt::pipe and $self->virgin() and not $opt::tee) {
	# Skip --joblog, --dryrun, --verbose
    } else {
	if($opt::ungroup) {
	    # NULL returnsize = 0 returnsize
	    $self->returnsize() or $self->add_returnsize(0);
	    if($Global::joblog and defined $self->{'exitstatus'}) {
		# Add to joblog when finished
		$self->print_joblog();
		# Printing is only relevant for grouped/--line-buffer output.
		$opt::ungroup and return;
	    }
	}

	# Check for disk full
	::exit_if_disk_full();

	if(($opt::dryrun or $Global::verbose)
	   and
	   not $self->{'verbose_printed'}
	   and
	   not $opt::sqlmaster
	   and
	   not $opt::sqlworker) {
	    $self->{'verbose_printed'}++;
	    if($Global::verbose <= 1) {
		print STDOUT $self->replaced(),"\n";
	    } else {
		# Verbose level > 1: Print the rsync and stuff
		print STDOUT $self->wrapped(),"\n";
	    }
	    # If STDOUT and STDERR are merged,
	    # we want the command to be printed first
	    # so flush to avoid STDOUT being buffered
	    flush STDOUT;
	}
    }
    my $returnsize = $self->returnsize();
    for my $fdno (sort { $a <=> $b } keys %Global::fd) {
	# Sort by file descriptor numerically: 1,2,3,..,9,10,11
	$fdno == 0 and next;
	my $out_fd = $Global::fd{$fdno};
	my $in_fh = $self->fh($fdno,"r");
	if(not $in_fh) {
	    if(not $Job::file_descriptor_warning_printed{$fdno}++) {
		# ::warning("File descriptor $fdno not defined\n");
	    }
	    next;
	}
	::debug("print", "File descriptor $fdno (", $self->fh($fdno,"name"), "):\n");
	if($opt::linebuffer) {
	    # Line buffered print out
	    $self->print_linebuffer($fdno,$in_fh,$out_fd);
	} elsif($opt::files) {
	    $self->print_files($fdno,$in_fh,$out_fd);
	} elsif($opt::tag or defined $opt::tagstring) {
	    $self->print_tag($fdno,$in_fh,$out_fd);
	} else {
	    $self->print_normal($fdno,$in_fh,$out_fd);
	}
	flush $out_fd;
    }
    ::debug("print", "<<joboutput @command\n");
    if(defined $self->{'exitstatus'}
       and not ($self->virgin() and $opt::pipe)) {
	if($Global::joblog and not $opt::sqlworker) {
	    # Add to joblog when finished
	    $self->print_joblog();
	}
	if($opt::sqlworker and not $opt::results) {
	    $Global::sql->output($self);
	}
	if($Global::csv) {
	    # Add output to CSV when finished
	    $self->print_csv();
	}
    }
    return $returnsize - $self->returnsize();
}

{
    my $header_printed;

    sub print_csv {
	my $self = shift;
	my $cmd;
	if($Global::verbose <= 1) {
	    $cmd = $self->replaced();
	} else {
	    # Verbose level > 1: Print the rsync and stuff
	    $cmd = "@command";
	}
	my $record_ref = $self->{'commandline'}{'arg_list_flat_orig'};

	if(not $header_printed) {
	    # Variable headers
	    # Normal => V1..Vn
	    # --header : => first value from column
	    my @V;
	    if($opt::header) {
		my $i = 1;
		@V = (map { $Global::input_source_header{$i++} }
		      @$record_ref[1..$#$record_ref]);
	    } else {
		my $V = "V1";
		@V = (map { $V++ } @$record_ref[1..$#$record_ref]);
	    }
	    print $Global::csv_fh
		(map { $$_ }
		 combine_ref("Seq", "Host", "Starttime", "JobRuntime",
			     "Send", "Receive", "Exitval", "Signal", "Command",
			     @V,
			     "Stdout","Stderr"
		 )),"\n";
	    $header_printed++;
	}
	# Memory optimization: Overwrite with the joined output
	$self->{'output'}{1} = join("", @{$self->{'output'}{1}});
	$self->{'output'}{2} = join("", @{$self->{'output'}{2}});
	print $Global::csv_fh
	    (map { $$_ }
	     combine_ref
	     ($self->seq(),
	      $self->sshlogin()->string(),
	      $self->starttime(), sprintf("%0.3f",$self->runtime()),
	      $self->transfersize(), $self->returnsize(),
	      $self->exitstatus(), $self->exitsignal(), \$cmd,
	      \@$record_ref[1..$#$record_ref],
	      \$self->{'output'}{1},
	      \$self->{'output'}{2})),"\n";
    }
}

sub combine_ref {
    # Inspired by Text::CSV_PP::_combine (by Makamaka Hannyaharamitu)
    my @part = @_;
    my $sep = $Global::csv;
    my $quot = '"';
    my @out = ();

    my $must_be_quoted;
    for my $column (@part) {
	# Memory optimization: Content transferred as reference
	if(ref $column ne "SCALAR") {
	    # Convert all columns to scalar references
	    my $v = $column;
	    $column = \$v;
	}
        if(not defined $$column) {
            $$column = '';
            next;
        }

        $must_be_quoted = 0;

        if($$column =~ s/$quot/$quot$quot/go){
	    # Replace " => ""
            $must_be_quoted ||=1;
        }
        if($$column =~ /[\s\Q$sep\E]/o){
	    # Put quotes around if the column contains ,
            $must_be_quoted ||=1;
        }

	$Global::use{"bytes"} ||= eval "use bytes; 1;";
	if ($$column =~ /\0/) {
	    # Contains \0 => put quotes around
	    $must_be_quoted ||=1;
        }
        if($must_be_quoted){
	    push @out, \$sep, \$quot, $column, \$quot;
        } else {
	    push @out, \$sep, $column;
	}
    }
    # Pop off a $sep
    shift @out;
    return @out;
}

sub print_files {
    # Print the name of the file containing stdout on stdout
    # Uses:
    #   $opt::pipe
    #   $opt::group = Print when job is done
    #   $opt::linebuffer = Print ASAP
    # Returns: N/A
    my $self = shift;
    my ($fdno,$in_fh,$out_fd) = @_;

    # If the job is dead: close printing fh. Needed for --compress
    close $self->fh($fdno,"w");
    if($? and $opt::compress) {
	::error($opt::compress_program." failed.");
	$self->set_exitstatus(255);
    }
    if($opt::compress) {
	# Kill the decompressor which will not be needed
	CORE::kill "TERM", $self->fh($fdno,"rpid");
    }
    close $in_fh;

    if($opt::pipe and $self->virgin()) {
	# Nothing was printed to this job:
	# cleanup unused tmp files if --files was set
	for my $fdno (1,2) {
	    ::rm($self->fh($fdno,"name"));
	    ::rm($self->fh($fdno,"unlink"));
	}
    } elsif($fdno == 1 and $self->fh($fdno,"name")) {
	print $out_fd $self->tag(),$self->fh($fdno,"name"),"\n";
	if($Global::membuffer) {
	    push @{$self->{'output'}{$fdno}}, $self->tag(), $self->fh($fdno,"name");
	}
	$self->add_returnsize(-s $self->fh($fdno,"name"));
	# Mark as printed - do not print again
	$self->set_fh($fdno,"name",undef);
    }
}

sub print_linebuffer {
    my $self = shift;
    my ($fdno,$in_fh,$out_fd) = @_;

    if(defined $self->{'exitstatus'}) {
	# If the job is dead: close printing fh. Needed for --compress
	close $self->fh($fdno,"w");
	if($? and $opt::compress) {
	    ::error($opt::compress_program." failed.");
	    $self->set_exitstatus(255);
	}
	if($opt::compress) {
	    # Blocked reading in final round
	    for my $fdno (1,2) {
		::set_fh_blocking($self->fh($fdno,'r'));
	    }
	}
    }
    if($opt::files or ($opt::results and not $Global::csv)) {
	if($fdno == 1 and not $self->fh($fdno,"printed")) {
	    print $out_fd $self->tag(),$self->fh($fdno,"name"),"\n";
	    if($Global::membuffer) {
		push @{$self->{'output'}{$fdno}}, $self->tag(), $self->fh($fdno,"name");
	    }
	    $self->set_fh($fdno,"printed",1);
	}
	# No need for reading $in_fh, as it it from "cat >/dev/null"
    } else {
	my $outputlength = 0;
	my $halfline_ref = $self->{'halfline'};
	my ($buf,$i,$rv);
	while($rv = sysread($in_fh, $buf, 131072)) {
	    $outputlength += $rv;
	    $i = (rindex($buf,"\n")+1) || (rindex($buf,"\r")+1);
	    if($i) {
		# One or more complete lines were found
		if($opt::tag or defined $opt::tagstring) {
		    # Replace ^ with $tag within the full line
		    my $tag = $self->tag();
		    substr($buf,0,$i-1) =~ s/(?<=[\n\r])/$tag/gm;
		    $i = (rindex($buf,"\n")+1) || (rindex($buf,"\r")+1);
		    unshift @$halfline_ref, $tag;
		}
		# Print the partial line (halfline) and the last half
		print $out_fd @$halfline_ref, substr($buf,0,$i);
		# Buffer in memory for SQL and CSV-output
		if($Global::membuffer) {
		    push(@{$self->{'output'}{$fdno}},
			 @$halfline_ref, substr($buf,0,$i));
		}
		# Remove the printed part by keeping the unprinted part
		@$halfline_ref = (substr($buf,$i));
	    } else {
		push @$halfline_ref, $buf;
	    }
	}
	$self->add_returnsize($outputlength);
    }
    if(defined $self->{'exitstatus'}) {
	if($opt::files or ($opt::results and not $Global::csv)) {
	    $self->add_returnsize(-s $self->fh($fdno,"name"));
	} else {
	    # If the job is dead: print the remaining partial line
	    # read remaining
	    my $halfline_ref = $self->{'halfline'};
	    if(grep /./, @$halfline_ref) {
		$self->add_returnsize(length join("",@$halfline_ref));
		if($opt::tag or defined $opt::tagstring) {
		    # Prepend $tag the the remaining half line
		    unshift @$halfline_ref, $self->tag();
		}
		# Print the partial line (halfline)
		print $out_fd @{$self->{'halfline'}};
		# Buffer in memory for SQL and CSV-output
		if($Global::membuffer) {
		    push(@{$self->{'output'}{$fdno}}, @$halfline_ref);
		}
		@$halfline_ref = ();
	    }
	}
	if($self->fh($fdno,"rpid") and CORE::kill 0, $self->fh($fdno,"rpid")) {
	    # decompress still running
	} else {
	    # decompress done: close fh
	    close $in_fh;
	    if($? and $opt::compress) {
		::error($opt::decompress_program." failed.");
		$self->set_exitstatus(255);
	    }
	}
    }
}

sub print_tag {
    my $self = shift;
    my ($fdno,$in_fh,$out_fd) = @_;
    my $buf;
    local $/ = "\n";
    close $self->fh($fdno,"w");
    if($? and $opt::compress) {
	::error($opt::compress_program." failed.");
	$self->set_exitstatus(255);
    }
    seek $in_fh, 0, 0;
    # $in_fh is now ready for reading at position 0
    my $tag = $self->tag();
    my $outputlength = 0;
    my @output;
    while(<$in_fh>) {
	print $out_fd $tag,$_;
	$outputlength += length $_;
	if($Global::membuffer) {
	    push @{$self->{'output'}{$fdno}}, $tag, $_;
	}
    }
    if($fdno == 1) {
	$self->add_returnsize($outputlength);
    }
    close $in_fh;
    if($? and $opt::compress) {
	::error($opt::decompress_program." failed.");
	$self->set_exitstatus(255);
    }
}

sub print_normal {
    my $self = shift;
    my ($fdno,$in_fh,$out_fd) = @_;
    my $buf;
    close $self->fh($fdno,"w");
    if($? and $opt::compress) {
	::error($opt::compress_program." failed.");
	$self->set_exitstatus(255);
    }
    seek $in_fh, 0, 0;
    # $in_fh is now ready for reading at position 0
    my $outputlength = 0;
    my @output;
    while(sysread($in_fh,$buf,131072)) {
	print $out_fd $buf;
	$outputlength += length $buf;
	if($Global::membuffer) {
	    push @{$self->{'output'}{$fdno}}, $buf;
	}
    }
    if($fdno == 1) {
	$self->add_returnsize($outputlength);
    }
    close $in_fh;
    if($? and $opt::compress) {
	::error($opt::decompress_program." failed.");
	$self->set_exitstatus(255);
    }
}

sub print_joblog {
    my $self = shift;
    my $cmd;
    if($Global::verbose <= 1) {
	$cmd = $self->replaced();
    } else {
	# Verbose level > 1: Print the rsync and stuff
	$cmd = "@command";
    }
    # Newlines make it hard to parse the joblog
    $cmd =~ s/\n/\0/g;
    print $Global::joblog
	join("\t", $self->seq(), $self->sshlogin()->string(),
	     $self->starttime(), sprintf("%10.3f",$self->runtime()),
	     $self->transfersize(), $self->returnsize(),
	     $self->exitstatus(), $self->exitsignal(), $cmd
	). "\n";
    flush $Global::joblog;
    $self->set_job_in_joblog();
}

sub tag {
    my $self = shift;
    if(not defined $self->{'tag'}) {
	if($opt::tag or defined $opt::tagstring) {
	    $self->{'tag'} = $self->{'commandline'}->
		replace_placeholders([$opt::tagstring],0,0)."\t";
	} else {
	    $self->{'tag'} = "";
	}
    }
    return $self->{'tag'};
}

sub hostgroups {
    my $self = shift;
    if(not defined $self->{'hostgroups'}) {
	$self->{'hostgroups'} = $self->{'commandline'}->{'arg_list'}[0][0]->{'hostgroups'};
    }
    return @{$self->{'hostgroups'}};
}

sub exitstatus {
    my $self = shift;
    return $self->{'exitstatus'};
}

sub set_exitstatus {
    my $self = shift;
    my $exitstatus = shift;
    if($exitstatus) {
	# Overwrite status if non-zero
	$self->{'exitstatus'} = $exitstatus;
    } else {
	# Set status but do not overwrite
	# Status may have been set by --timeout
	$self->{'exitstatus'} ||= $exitstatus;
    }
    $opt::sqlworker and
	$Global::sql->update("SET Exitval = ? WHERE Seq = ".$self->seq(),
			     $exitstatus);
}

sub reset_exitstatus {
    my $self = shift;
    undef $self->{'exitstatus'};
}

sub exitsignal {
    my $self = shift;
    return $self->{'exitsignal'};
}

sub set_exitsignal {
    my $self = shift;
    my $exitsignal = shift;
    $self->{'exitsignal'} = $exitsignal;
    $opt::sqlworker and
	$Global::sql->update("SET _Signal = ? WHERE Seq = ".$self->seq(),
			     $exitsignal);
}

{
    my $status_printed;
    my $total_jobs;

    sub should_we_halt {
	# Should we halt? Immediately? Gracefully?
	# Returns: N/A
	my $job = shift;
	my $limit;
	if($job->exitstatus() or $job->exitsignal()) {
	    # Job failed
	    $Global::exitstatus++;
	    $Global::total_failed++;
	    if($Global::halt_fail) {
		::status("$Global::progname: This job failed:",
			 $job->replaced());
		$limit = $Global::total_failed;
	    }
	} elsif($Global::halt_success) {
	    ::status("$Global::progname: This job succeeded:",
		     $job->replaced());
	    $limit = $Global::total_completed-$Global::total_failed;
	}
	if($Global::halt_done) {
	    ::status("$Global::progname: This job finished:",
		     $job->replaced());
	    $limit = $Global::total_completed;
	}
	if(not defined $limit) {
	    return ""
	}
	#  --halt # => 1..100 (number of jobs failed, 101 means > 100)
	#  --halt % => 1..100 (pct of jobs failed)
	if($Global::halt_pct and not $Global::halt_count) {
	    $total_jobs ||= $Global::JobQueue->total_jobs();
	    # From the pct compute the number of jobs that must fail/succeed
	    $Global::halt_count = $total_jobs * $Global::halt_pct;
	}
	if($limit >= $Global::halt_count) {
	    # At least N jobs have failed/succeded/completed
	    # or at least N% have failed/succeded/completed
	    # So we should prepare for exit
	    if($Global::halt_fail or $Global::halt_done) {
		# Set exit status
		if(not defined $Global::halt_exitstatus) {
		    if($Global::halt_pct) {
			# --halt now,fail=X% or soon,fail=X%
			# --halt now,done=X% or soon,done=X%
			$Global::halt_exitstatus =
			    ::ceil($Global::total_failed / $total_jobs * 100);
		    } elsif($Global::halt_count) {
			# --halt now,fail=X or soon,fail=X
			# --halt now,done=X or soon,done=X
			$Global::halt_exitstatus = ::min($Global::total_failed,101);
		    }
		    if($Global::halt_count and $Global::halt_count == 1) {
			# --halt now,fail=1 or soon,fail=1
			# --halt now,done=1 or soon,done=1
			$Global::halt_exitstatus = $job->exitstatus();
		    }
		}
		::debug("halt","Pct: ",$Global::halt_pct,
			" count: ",$Global::halt_count,
			" status: ",$Global::halt_exitstatus,"\n");
	    } elsif($Global::halt_success) {
		$Global::halt_exitstatus = 0;
	    }
	    if($Global::halt_when eq "soon"
	       and scalar(keys %Global::running) > 0) {
		::status
		    ("$Global::progname: Starting no more jobs. ".
		     "Waiting for ". (keys %Global::running).
		     " jobs to finish.");
		$Global::start_no_new_jobs ||= 1;
	    }
	    return($Global::halt_when);
	}
	return "";
    }
}


package CommandLine;

sub new {
    my $class = shift;
    my $seq = shift;
    my $commandref = shift;
    $commandref || die;
    my $arg_queue = shift;
    my $context_replace = shift;
    my $max_number_of_args = shift; # for -N and normal (-n1)
    my $transfer_files = shift;
    my $return_files = shift;
    my $replacecount_ref = shift;
    my $len_ref = shift;
    my %replacecount = %$replacecount_ref;
    my %len = %$len_ref;
    for (keys %$replacecount_ref) {
	# Total length of this replacement string {} replaced with all args
	$len{$_} = 0;
    }
    return bless {
	'command' => $commandref,
	'seq' => $seq,
	'len' => \%len,
	'arg_list' => [],
	'arg_list_flat' => [],
	'arg_list_flat_orig' => [undef],
	'arg_queue' => $arg_queue,
	'max_number_of_args' => $max_number_of_args,
	'replacecount' => \%replacecount,
	'context_replace' => $context_replace,
	'transfer_files' => $transfer_files,
	'return_files' => $return_files,
	'replaced' => undef,
    }, ref($class) || $class;
}

sub seq {
    my $self = shift;
    return $self->{'seq'};
}

sub set_seq {
    my $self = shift;
    $self->{'seq'} = shift;
}

sub slot {
    # Find the number of a free job slot and return it
    # Uses:
    #   @Global::slots - list with free jobslots
    # Returns:
    #   $jobslot = number of jobslot
    my $self = shift;
    if(not $self->{'slot'}) {
	if(not @Global::slots) {
	    # $max_slot_number will typically be $Global::max_jobs_running
	    push @Global::slots, ++$Global::max_slot_number;
	}
	$self->{'slot'} = shift @Global::slots;
    }
    return $self->{'slot'};
}

{
    my $already_spread;

    sub populate {
	# Add arguments from arg_queue until the number of arguments or
	# max line length is reached
	# Uses:
	#   $Global::minimal_command_line_length
	#   $opt::cat
	#   $opt::fifo
	#   $Global::JobQueue
	#   $opt::m
	#   $opt::X
	#   $Global::max_jobs_running
	# Returns: N/A
	my $self = shift;
	my $next_arg;
	my $max_len = $Global::minimal_command_line_length
	    || Limits::Command::max_length();

	if($opt::cat or $opt::fifo) {
	    # Get the empty arg added by --pipepart (if any)
	    $Global::JobQueue->{'commandlinequeue'}->{'arg_queue'}->get();
	    # $PARALLEL_TMP will point to a tempfile that will be used as {}
	    $Global::JobQueue->{'commandlinequeue'}->{'arg_queue'}->
		unget([Arg->new('$PARALLEL_TMP')]);
	}
	while (not $self->{'arg_queue'}->empty()) {
	    $next_arg = $self->{'arg_queue'}->get();
	    if(not defined $next_arg) {
		next;
	    }
	    $self->push($next_arg);
	    if($self->len() >= $max_len) {
		# Command length is now > max_length
		# If there are arguments: remove the last
		# If there are no arguments: Error
		# TODO stuff about -x opt_x
		if($self->number_of_args() > 1) {
		    # There is something to work on
		    $self->{'arg_queue'}->unget($self->pop());
		    last;
		} else {
		    my $args = join(" ", map { $_->orig() } @$next_arg);
		    ::error("Command line too long (".
			    $self->len(). " >= ".
			    $max_len.
			    ") at input ".
			    $self->{'arg_queue'}->arg_number().
			    ": ".
			    ((length $args > 50) ?
			     (substr($args,0,50))."..." :
			     $args));
		    $self->{'arg_queue'}->unget($self->pop());
		    ::wait_and_exit(255);
		}
	    }

	    if(defined $self->{'max_number_of_args'}) {
		if($self->number_of_args() >= $self->{'max_number_of_args'}) {
		    last;
		}
	    }
	}
	if(($opt::m or $opt::X) and not $already_spread
	   and $self->{'arg_queue'}->empty() and $Global::max_jobs_running) {
	    # -m or -X and EOF => Spread the arguments over all jobslots
	    # (unless they are already spread)
	    $already_spread ||= 1;
	    if($self->number_of_args() > 1) {
		$self->{'max_number_of_args'} =
		    ::ceil($self->number_of_args()/$Global::max_jobs_running);
		$Global::JobQueue->{'commandlinequeue'}->{'max_number_of_args'} =
		    $self->{'max_number_of_args'};
		$self->{'arg_queue'}->unget($self->pop_all());
		while($self->number_of_args() < $self->{'max_number_of_args'}) {
		    $self->push($self->{'arg_queue'}->get());
		}
	    }
	    $Global::JobQueue->flush_total_jobs();
	}

	if($opt::sqlmaster) {
	    # Insert the V1..Vn for this $seq in SQL table instead of generating one
	    $Global::sql->insert_records($self->seq(), $self->{'command'},
					 $self->{'arg_list_flat_orig'});
	}
    }
}

sub push {
    # Add one or more records as arguments
    # Returns: N/A
    my $self = shift;
    my $record = shift;
    push @{$self->{'arg_list_flat_orig'}}, map { $_->orig() } @$record;
    push @{$self->{'arg_list_flat'}}, @$record;
    push @{$self->{'arg_list'}}, $record;
    # Make @arg available for {= =}
    *Arg::arg = $self->{'arg_list_flat_orig'};

    my $quote_arg = $Global::noquote ? 0 : not $Global::quoting;
    for my $perlexpr (keys %{$self->{'replacecount'}}) {
	if($perlexpr =~ /^(\d+) /) {
	    # Positional
	    defined($record->[$1-1]) or next;
	    $self->{'len'}{$perlexpr} +=
		length $record->[$1-1]->replace($perlexpr,$quote_arg,$self);
	} else {
	    for my $arg (@$record) {
		if(defined $arg) {
		    $self->{'len'}{$perlexpr} +=
			length $arg->replace($perlexpr,$quote_arg,$self);
		}
	    }
	}
    }
}

sub pop {
    # Remove last argument
    # Returns:
    #   the last record
    my $self = shift;
    my $record = pop @{$self->{'arg_list'}};
    # pop off arguments from @$record
    splice @{$self->{'arg_list_flat_orig'}}, -($#$record+1), $#$record+1;
    splice @{$self->{'arg_list_flat'}}, -($#$record+1), $#$record+1;
    my $quote_arg = $Global::noquote ? 0 : not $Global::quoting;
    for my $perlexpr (keys %{$self->{'replacecount'}}) {
	if($perlexpr =~ /^(\d+) /) {
	    # Positional
	    defined($record->[$1-1]) or next;
	    $self->{'len'}{$perlexpr} -=
		length $record->[$1-1]->replace($perlexpr,$quote_arg,$self);
	} else {
	    for my $arg (@$record) {
		if(defined $arg) {
		    $self->{'len'}{$perlexpr} -=
			length $arg->replace($perlexpr,$quote_arg,$self);
		}
	    }
	}
    }
    return $record;
}

sub pop_all {
    # Remove all arguments and zeros the length of replacement perlexpr
    # Returns:
    #   all records
    my $self = shift;
    my @popped = @{$self->{'arg_list'}};
    for my $perlexpr (keys %{$self->{'replacecount'}}) {
	$self->{'len'}{$perlexpr} = 0;
    }
    $self->{'arg_list'} = [];
    $self->{'arg_list_flat_orig'} = [undef];
    $self->{'arg_list_flat'} = [];
    return @popped;
}

sub number_of_args {
    # The number of records
    # Returns:
    #   number of records
    my $self = shift;
    # This is really the number of records
    return $#{$self->{'arg_list'}}+1;
}

sub number_of_recargs {
    # The number of args in records
    # Returns:
    #   number of args records
    my $self = shift;
    my $sum = 0;
    my $nrec = scalar @{$self->{'arg_list'}};
    if($nrec) {
	$sum = $nrec * (scalar @{$self->{'arg_list'}[0]});
    }
    return $sum;
}

sub args_as_string {
    # Returns:
    #  all unmodified arguments joined with ' ' (similar to {})
    my $self = shift;
    return (join " ", map { $_->orig() }
	    map { @$_ } @{$self->{'arg_list'}});
}

sub results_out {
    sub max_file_name_length {
	# Figure out the max length of a subdir
	# TODO and the max total length
	# Ext4 = 255,130816
	# Uses:
	#   $Global::max_file_length is set
	# Returns:
	#   $Global::max_file_length
	my $testdir = shift;

	my $upper = 8_000_000;
	# Dir length of 8 chars is supported everywhere
	my $len = 8;
	my $dir = "x"x$len;
	do {
	    rmdir($testdir."/".$dir);
	    $len *= 16;
	    $dir = "x"x$len;
	} while ($len < $upper and mkdir $testdir."/".$dir);
	# Then search for the actual max length between $len/16 and $len
	my $min = $len/16;
	my $max = $len;
	while($max-$min > 5) {
	    # If we are within 5 chars of the exact value:
	    # it is not worth the extra time to find the exact value
	    my $test = int(($min+$max)/2);
	    $dir = "x"x$test;
	    if(mkdir $testdir."/".$dir) {
		rmdir($testdir."/".$dir);
		$min = $test;
	    } else {
		$max = $test;
	    }
	}
	$Global::max_file_length = $min;
	return $min;
    }

    my $self = shift;
    my $out = $self->replace_placeholders([$opt::results],0,0);
    if($out eq $opt::results) {
	# $opt::results simple string: Append args_as_dirname
	my $args_as_dirname = $self->args_as_dirname();
	# Output in: prefix/name1/val1/name2/val2/stdout
	$out = $opt::results."/".$args_as_dirname;
	if(-d $out or eval{ File::Path::mkpath($out); }) {
	    # OK
	} else {
	    # mkpath failed: Argument probably too long.
	    # Set $Global::max_file_length, which will keep the individual
	    # dir names shorter than the max length
	    max_file_name_length($opt::results);
	    $args_as_dirname = $self->args_as_dirname();
	    # prefix/name1/val1/name2/val2/
	    $out = $opt::results."/".$args_as_dirname;
	    File::Path::mkpath($out);
	}
	$out .="/";
    } else {
	if($out =~ m:/$:) {
	    # / = dir
	    if(-d $out or eval{ File::Path::mkpath($out); }) {
		# OK
	    } else {
		::error("Cannot make dir '$out'.");
		::wait_and_exit(255);
	    }
	} else {
	    $out =~ m:(.*)/:;
	    File::Path::mkpath($1);
	}
    }
    return $out;
}

sub args_as_dirname {
    # Returns:
    #  all unmodified arguments joined with '/' (similar to {})
    #  \t \0 \\ and / are quoted as: \t \0 \\ \_
    # If $Global::max_file_length: Keep subdirs < $Global::max_file_length
    my $self = shift;
    my @res = ();

    for my $rec_ref (@{$self->{'arg_list'}}) {
	# If headers are used, sort by them.
	# Otherwise keep the order from the command line.
	my @header_indexes_sorted = header_indexes_sorted($#$rec_ref+1);
	for my $n (@header_indexes_sorted) {
	    CORE::push(@res,
		 $Global::input_source_header{$n},
		 map { my $s = $_;
		       #  \t \0 \\ and / are quoted as: \t \0 \\ \_
		       $s =~ s/\\/\\\\/g;
		       $s =~ s/\t/\\t/g;
		       $s =~ s/\0/\\0/g;
		       $s =~ s:/:\\_:g;
		       if($Global::max_file_length) {
			   # Keep each subdir shorter than the longest
			   # allowed file name
			   $s = substr($s,0,$Global::max_file_length);
		       }
		       $s; }
		 $rec_ref->[$n-1]->orig());
	}
    }
    return join "/", @res;
}

sub header_indexes_sorted {
    # Sort headers first by number then by name.
    # E.g.: 1a 1b 11a 11b
    # Returns:
    #  Indexes of %Global::input_source_header sorted
    my $max_col = shift;

    no warnings 'numeric';
    for my $col (1 .. $max_col) {
	# Make sure the header is defined. If it is not: use column number
	if(not defined $Global::input_source_header{$col}) {
	    $Global::input_source_header{$col} = $col;
	}
    }
    my @header_indexes_sorted = sort {
	# Sort headers numerically then asciibetically
	$Global::input_source_header{$a} <=> $Global::input_source_header{$b}
	or
	    $Global::input_source_header{$a} cmp $Global::input_source_header{$b}
    } 1 .. $max_col;
    return @header_indexes_sorted;
}

sub len {
    # Uses:
    #   $opt::shellquote
    # The length of the command line with args substituted
    my $self = shift;
    my $len = 0;
    # Add length of the original command with no args
    # Length of command w/ all replacement args removed
    $len += $self->{'len'}{'noncontext'} + @{$self->{'command'}} -1;
    ::debug("length", "noncontext + command: $len\n");
    my $recargs = $self->number_of_recargs();
    if($self->{'context_replace'}) {
	# Context is duplicated for each arg
	$len += $recargs * $self->{'len'}{'context'};
	for my $replstring (keys %{$self->{'replacecount'}}) {
	    # If the replacements string is more than once: mulitply its length
	    $len += $self->{'len'}{$replstring} *
		$self->{'replacecount'}{$replstring};
	    ::debug("length", $replstring, " ", $self->{'len'}{$replstring}, "*",
		    $self->{'replacecount'}{$replstring}, "\n");
	}
	# echo 11 22 33 44 55 66 77 88 99 1010
	# echo 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
	# 5 +  ctxgrp*arg
	::debug("length", "Ctxgrp: ", $self->{'len'}{'contextgroups'},
		" Groups: ", $self->{'len'}{'noncontextgroups'}, "\n");
	# Add space between context groups
	$len += ($recargs-1) * ($self->{'len'}{'contextgroups'});
    } else {
	# Each replacement string may occur several times
	# Add the length for each time
	$len += 1*$self->{'len'}{'context'};
	::debug("length", "context+noncontext + command: $len\n");
	for my $replstring (keys %{$self->{'replacecount'}}) {
	    # (space between regargs + length of replacement)
	    # * number this replacement is used
	    $len += ($recargs -1 + $self->{'len'}{$replstring}) *
		$self->{'replacecount'}{$replstring};
	}
    }
    if($Global::quoting) {
	# Pessimistic length if -q is set
	# Worse than worst case: every char needs to be quoted with \
	$len *= 2;
    }
    if($opt::shellquote) {
	# Pessimistic length if --shellquote is set
	# Worse than worst case: every char needs to be quoted with \ twice
	$len *= 4;
    }
    # If we are using --env, add the prefix for that, too.
    $len += 0;
    return $len;
}

sub replaced {
    # Uses:
    #   $Global::noquote
    #   $Global::quoting
    # Returns:
    #   $replaced = command with place holders replaced and prepended
    my $self = shift;
    if(not defined $self->{'replaced'}) {
	# Don't quote arguments if the input is the full command line
	my $quote_arg = $Global::noquote ? 0 : not $Global::quoting;
	# or if ($opt::cat or $opt::pipe) as they use $PARALLEL_TMP
	$quote_arg = ($opt::cat || $opt::fifo) ? 0 : $quote_arg;
	$self->{'replaced'} = $self->
	    replace_placeholders($self->{'command'},$Global::quoting,
				 $quote_arg);
	my $len = length $self->{'replaced'};
	if ($len != $self->len()) {
	    ::debug("length", $len, " != ", $self->len(),
		    " ", $self->{'replaced'}, "\n");
	} else {
	    ::debug("length", $len, " == ", $self->len(),
		    " ", $self->{'replaced'}, "\n");
	}
    }
    return $self->{'replaced'};
}

{
    my @target;
    my $context_replace;
    my $perl_expressions_as_re;
    my @arg;
    my %words_with_rpl_strings;

    sub fish_out_words_with_rpl_strings {
	if(not $words_with_rpl_strings{$context_replace,@target}) {
	    my %word;
	    for (@target) {
		my $tt = $_;
		::debug("replace", "Target: $tt");
		# Command line template:
		#   a{1}b{}c{}d
		# becomes:
		#   a{=1 $_=$_ =}b{= $_=$_ =}c{= $_=$_ =}d
		# becomes:
		#   a\257<1 $_=$_ \257>b\257< $_=$_ \257>c\257< $_=$_ \257>d
		# Input A B C (no context) becomes:
		#    A B C => aAbA B CcA B Cd
		# Input A B C (context -X) becomes:
		#    A B C => aAbAcAd aAbBcBd aAbCcCd
		if($context_replace) {
		    while($tt =~ s/([^\s\257]*  # before {=
                     (?:
                      \257<       # {=
                      (?: (?! \257[<>]). )* # The perl expression
                      \257>       # =}
                      [^\s\257]*  # after =}
                     )+)/ /xs) {
			# $1 = pre \257< perlexpr \257> post
			$word{"$1"} ||= 1;
		    }
		} else {
		    while($tt =~ s/( \257<(?: (?! \257[<>]). )*\257> )//xs) {
			# $1 = \257< perlexpr \257>
			$word{$1} ||= 1;
		    }
		}
	    }
	    @{$words_with_rpl_strings{$context_replace,@target}} = keys %word
	}
	return @{$words_with_rpl_strings{$context_replace,@target}};
    }

    sub replace_placeholders {
	# Replace foo{}bar with fooargbar
	# Uses:
	#   @Arg::arg = arguments as strings to be use in {= =}
	# Input:
	#   $targetref = command as shell words
	#   $quote = should everything be quoted?
	#   $quote_arg = should replaced arguments be quoted?
	# Returns:
	#   @target with placeholders replaced
	my $self = shift;
	my $targetref = shift;
	my $quote = shift;
	my $quote_arg = shift;
	my %replace;
	# -X = context replace (fish_out_words_with_rpl_strings)
	$context_replace = $self->{'context_replace'};
	@target = @$targetref;
	::debug("replace", "Replace @target\n");
	if(not @target) {
	    # @target is empty: Return empty array
	    return @target;
	}
	# Make it possible to use $arg[2] in {= =}
	*Arg::arg = $self->{'arg_list_flat_orig'};
	# Flat list:
	# $self->{'arg_list'} = [ [Arg11, Arg12], [Arg21, Arg22], [Arg31, Arg32] ]
	# $self->{'arg_list_flat'} = [ Arg11, Arg12, Arg21, Arg22, Arg31, Arg32 ]
	if(not @{$self->{'arg_list_flat'}}) {
	    @{$self->{'arg_list_flat'}} = Arg->new("");
	}
	my $argref = $self->{'arg_list_flat'};
	# Number of arguments - used for positional arguments
	my $n = $#$argref+1;

	# $self is actually a CommandLine-object,
	# but it looks nice to be able to say {= $job->slot() =}
	my $job = $self;
	$perl_expressions_as_re =
	    join("|", map {s/^-?\d+//; "\Q$_\E"} keys %{$self->{'replacecount'}});
	# Fish out the words that have replacement strings in them
	for my $word (fish_out_words_with_rpl_strings()) {
	    # word = AB \257< perlexpr \257> CD \257< perlexpr \257> EF
	    ::debug("replace", "Replacing in $word\n");
	    my $normal_replace;

	    # for each arg:
	    #   replace replacement strings with replacement in the word value
	    #   push to replace word value
	    for my $arg (@$argref) {
		my $val = $word;
		# Replace {= perl expr =} with value for each arg
		$val =~ s{\257<(-?\d+)?($perl_expressions_as_re)\257>}
		{
			if($1) {
			    # Positional replace
			    # Find the relevant arg and replace it
			    ($argref->[$1 > 0 ? $1-1 : $n+$1] ? # If defined: replace
			     $argref->[$1 > 0 ? $1-1 : $n+$1]->
			     replace($2,$quote_arg,$self)
			     : "");
			} else {
			    # Normal replace
			    $normal_replace ||= 1;
			    ($arg ? $arg->replace($2,$quote_arg,$self) : "");
			}
		    }gxe;
		if($quote) {
		    CORE::push(@{$replace{::shell_quote_scalar($word)}},
			       ::shell_quote_scalar($val));
		} else {
		    CORE::push(@{$replace{$word}}, $val);
		}
		# No normal replacements => only run once
		$normal_replace or last;
	    }
	}
	*Arg::arg = [];
	if($quote) {
	    @target = ::shell_quote(@target);
	}
	if(%replace) {
	    # Substitute the replace strings with the replacement values
	    # Must be sorted by length if a short word is a substring of a long word
	    my $regexp = join('|', map { my $s = $_; $s =~ s/(\W)/\\$1/g; $s }
			      sort { length $b <=> length $a } keys %replace);
	    for(@target) {
		s/($regexp)/join(" ",@{$replace{$1}})/ge;
	    }
	}
	if($Global::escape_string_present) {
	    # Command line contains \257: Unescape it \257\256 => \257
	    # If a replacement resulted in \257\256
	    # it will have been escaped into \\\257\\\\256
	    # and will not be matched below
	    for(@target) {
		s/\257\256/\257/g;
	    }
	    if($opt::q) {
		# \257 will be quoted too much
		for(@target) {
		    s/\\\257\\\256/\\\257/g;
		}
	    }
	}
	::debug("replace", "Return @target\n");
	return wantarray ? @target : "@target";
    }
}

sub skip {
    # Skip this job
    my $self = shift;
    $self->{'skip'} = 1;
}


package CommandLineQueue;

sub new {
    my $class = shift;
    my $commandref = shift;
    my $read_from = shift;
    my $context_replace = shift || 0;
    my $max_number_of_args = shift;
    my $transfer_files = shift;
    my $return_files = shift;
    my @unget = ();
    my ($count,$posrpl,$perlexpr);
    my ($replacecount_ref, $len_ref);
    my @command = @$commandref;
    my $dummy = '';
    my $seq = 1;
    # If the first command start with '-' it is probably an option
    if($command[0] =~ /^\s*(-\S+)/) {
	# Is this really a command in $PATH starting with '-'?
	my $cmd = $1;
	if(not ::which($cmd)) {
	    ::error("Command ($cmd) starts with '-'. Is this a wrong option?");
	    ::wait_and_exit(255);
	}
    }
    # Replace replacement strings with {= perl expr =}
    # '{=' 'perlexpr' '=}'  => '{= perlexpr =}'
    @command = merge_rpl_parts(@command);

    # Protect matching inside {= perl expr =}
    # by replacing {= and =} with \257< and \257>
    # in options that can contain replacement strings:
    # @command, --transferfile, --return,
    # --tagstring, --workdir, --results
    for(@command, @$transfer_files, @$return_files,
	$opt::tagstring, $opt::workdir, $opt::results, $opt::retries) {
	# Skip if undefined
	$_ or next;
	# Escape \257 => \257\256
	$Global::escape_string_present += s/\257/\257\256/g;
	# Needs to match rightmost left parens (Perl defaults to leftmost)
	# to deal with: {={==} and {={==}=}
	# Replace {= -> \257<  and  =} -> \257>
	#
	# Complex way to do:
	#   s/{=(.*)=}/\257<$1\257>/g
	# which would not work
	s[\Q$Global::parensleft\E # Match {=
          # Match . unless the next string is {= or =}
          #   needed to force matching the shortest {= =}
          ((?:(?! \Q$Global::parensleft\E|\Q$Global::parensright\E ).)*?)
          \Q$Global::parensright\E ] # Match =}
	{\257<$1\257>}gx;
	for my $rpl (sort { length $b <=> length $a } keys %Global::rpl) {
	    # Replace long --rpl's before short ones, as a short may be a
	    # substring of a long:
	    #   --rpl '% s/a/b/' --rpl '%% s/b/a/'
	    #
	    # Replace the shorthand string (--rpl)
	    # with the {= perl expr =}
	    #
	    # Avoid searching for shorthand strings inside existing {= perl expr =}
	    #
	    # Replace $$1 in {= perl expr =} with groupings in shorthand string
	    #
	    #   --rpl '{/(\.\S+)/(\.\S+)} s/$$1/$$2/g;'
	    #     echo {/.tar/.gz} ::: UU.tar.gz
	    my ($prefix,$grp_regexp,$postfix) =
		$rpl =~ /^( [^(]*  )    # Prefix - e.g. {%%
                          ( \(.*\) )?   # Group capture regexp - e.g (.*)
                          ( [^)]*  )$   # Postfix - e.g }
                        /xs;
	    $grp_regexp ||= '';
	    my $rplval = $Global::rpl{$rpl};
	    while(s{( (?: ^|\257> ) (?: (?! \257[<>])(?:.|\n) )*? )
                      # Don't replace after \257 unless \257>
                    \Q$prefix\E $grp_regexp \Q$postfix\E}
		  {
		      # The start remains the same
		      my $unchanged = $1;
		      # Dummy entry to start at 1.
		      my @grp = (1);
		      # $2 = first ()-group in $grp_regexp
		      # Put $2 in $grp[1], Put $3 in $grp[2]
		      # so first ()-group in $grp_regexp is $grp[1];
		      for(my $i = 2; defined $grp[$#grp]; $i++) {
			  push @grp, eval '$'.$i;
		      }
		      my $rv = $rplval;
		      # replace $$1 with $_pAr_gRp1, $$2 with $_pAr_gRp2
		      # in the code to be executed
		      $rv =~ s/\$\$ (\d+)/\$_pAr_gRp$1/gx;
		      # prepend with $_pAr_gRp1 = perlquote($1),
		      my $set_args = "";
		      for(my $i = 1;defined $grp[$i]; $i++) {
			  $set_args .= "\$_pAr_gRp$i = \"" .
			      ::perl_quote_scalar($grp[$i]) . "\";";
		      }
		      $unchanged . "\257<" . $set_args . $rv . "\257>"
		  }gxes) {
	    }
	    # Do the same for the positional replacement strings
	    $posrpl = $rpl;
	    if($posrpl =~ s/^\{//) {
		# Only do this if the shorthand start with {
		$prefix=~s/^\{//;
		# Don't replace after \257 unless \257>
		while(s{( (?: ^|\257> ) (?: (?! \257[<>]). )*? )
		  \{(-?\d+) \s* \Q$prefix\E $grp_regexp \Q$postfix\E}
		      {
		      # The start remains the same
		      my $unchanged = $1;
		      my $position = $2;
		      # Dummy entry to start at 1.
		      my @grp = (1);
		      # $3 = first ()-group in $grp_regexp
		      # Put $3 in $grp[1], Put $4 in $grp[2]
		      # so first ()-group in $grp_regexp is $grp[1];
		      for(my $i = 3; defined $grp[$#grp]; $i++) {
			  push @grp, eval '$'.$i;
		      }
		      my $rv = $rplval;
		      # replace $$1 with $_pAr_gRp1, $$2 with $_pAr_gRp2
		      # in the code to be executed
		      $rv =~ s/\$\$ (\d+)/\$_pAr_gRp$1/gx;
		      # prepend with $_pAr_gRp1 = perlquote($1),
		      my $set_args = "";
		      for(my $i = 1;defined $grp[$i]; $i++) {
			  $set_args .= "\$_pAr_gRp$i = \"" .
			      ::perl_quote_scalar($grp[$i]) . "\";";
		      }
		      $unchanged . "\257<" . $position . $set_args . $rv . "\257>"
		  }gxes) {
		}
	    }
	}
    }

    # Add {} if no replacement strings in @command
    ($replacecount_ref, $len_ref, @command) =
	replacement_counts_and_lengths($transfer_files,$return_files,@command);
    if("@command" =~ /^[^ \t\n=]*\257</) {
	# Replacement string is (part of) the command (and not just
	# argument or variable definition V1={})
	# E.g. parallel {}, parallel my_{= s/_//=}, parallel {2}
	# Do no quote (Otherwise it will fail if the input contains spaces)
	$Global::noquote = 1;
    }

    if($opt::sqlmaster and $Global::sql->append()) {
	$seq = $Global::sql->max_seq() + 1;
    }

    return bless {
	'unget' => \@unget,
	'command' => \@command,
	'replacecount' => $replacecount_ref,
	'arg_queue' => RecordQueue->new($read_from,$opt::colsep),
	'context_replace' => $context_replace,
	'len' => $len_ref,
	'max_number_of_args' => $max_number_of_args,
	'size' => undef,
	'transfer_files' => $transfer_files,
	'return_files' => $return_files,
	'seq' => $seq,
    }, ref($class) || $class;
}

sub merge_rpl_parts {
    # '{=' 'perlexpr' '=}'  => '{= perlexpr =}'
    # Input:
    #   @in = the @command as given by the user
    # Uses:
    #   $Global::parensleft
    #   $Global::parensright
    # Returns:
    #   @command with parts merged to keep {= and =} as one
    my @in = @_;
    my @out;
    my $l = quotemeta($Global::parensleft);
    my $r = quotemeta($Global::parensright);

    while(@in) {
	my $s = shift @in;
	$_ = $s;
	# Remove matching (right most) parens
	while(s/(.*)$l.*?$r/$1/o) {}
	if(/$l/o) {
	    # Missing right parens
	    while(@in) {
		$s .= " ".shift @in;
		$_ = $s;
		while(s/(.*)$l.*?$r/$1/o) {}
		if(not /$l/o) {
		    last;
		}
	    }
	}
	push @out, $s;
    }
    return @out;
}

sub replacement_counts_and_lengths {
    # Count the number of different replacement strings.
    # Find the lengths of context for context groups and non-context
    # groups.
    # If no {} found in @command: add it to @command
    #
    # Input:
    #   \@transfer_files = array of filenames to transfer
    #   \@return_files = array of filenames to return
    #   @command = command template
    # Output:
    #   \%replacecount, \%len, @command
    my $transfer_files = shift;
    my $return_files = shift;
    my @command = @_;
    my (%replacecount,%len);
    my $sum = 0;
    while($sum == 0) {
	# Count how many times each replacement string is used
	my @cmd = @command;
	my $contextlen = 0;
	my $noncontextlen = 0;
	my $contextgroups = 0;
	for my $c (@cmd) {
	    while($c =~ s/ \257<( (?: (?! \257[<>]). )*?)\257> /\000/xs) {
		# %replacecount = { "perlexpr" => number of times seen }
		# e.g { "s/a/b/" => 2 }
		$replacecount{$1}++;
		$sum++;
	    }
	    # Measure the length of the context around the {= perl expr =}
	    # Use that {=...=} has been replaced with \000 above
	    # So there is no need to deal with \257<
	    while($c =~ s/ (\S*\000\S*) //xs) {
		my $w = $1;
		$w =~ tr/\000//d; # Remove all \000's
		$contextlen += length($w);
		$contextgroups++;
	    }
	    # All {= perl expr =} have been removed: The rest is non-context
	    $noncontextlen += length $c;
	}
	for(@$transfer_files, @$return_files,
	    $opt::tagstring, $opt::workdir, $opt::results, $opt::retries) {
	    # Options that can contain replacement strings
	    $_ or next;
	    my $t = $_;
	    while($t =~ s/ \257<( (?: (?! \257[<>]). )* )\257> //xs) {
		# %replacecount = { "perlexpr" => number of times seen }
		# e.g { "$_++" => 2 }
		# But for tagstring we just need to mark it as seen
		$replacecount{$1} ||= 1;
	    }
	}
	if($opt::bar) {
	    # If the command does not contain {} force it to be computed
	    # as it is being used by --bar
	    $replacecount{""} ||= 1;
	}

	$len{'context'} = 0+$contextlen;
	$len{'noncontext'} = $noncontextlen;
	$len{'contextgroups'} = $contextgroups;
	$len{'noncontextgroups'} = @cmd-$contextgroups;
	::debug("length", "@command Context: ", $len{'context'},
		" Non: ", $len{'noncontext'}, " Ctxgrp: ", $len{'contextgroups'},
		" NonCtxGrp: ", $len{'noncontextgroups'}, "\n");
	if($sum == 0) {
	    if(not @command) {
		# Default command = {}
		@command = ("\257<\257>");
	    } elsif(($opt::pipe or $opt::pipepart)
		    and not $opt::fifo and not $opt::cat) {
		# With --pipe / --pipe-part you can have no replacement
		last;
	    } else {
		# Append {} to the command if there are no {...}'s and no {=...=}
		push @command, ("\257<\257>");
	    }
	}
    }
    return(\%replacecount,\%len,@command);
}

sub get {
    my $self = shift;
    if(@{$self->{'unget'}}) {
	my $cmd_line = shift @{$self->{'unget'}};
	return ($cmd_line);
    } else {
	if($opt::sqlworker) {
	    # Get the sequence number from the SQL table
	    $self->set_seq($SQL::next_seq);
	    # Get the command from the SQL table
	    $self->{'command'} = $SQL::command_ref;
	    my @command;
	    # Recompute replace counts based on the read command
	    ($self->{'replacecount'},
	     $self->{'len'}, @command) =
		replacement_counts_and_lengths($self->{'transfer_files'},
					       $self->{'return_files'},
					       @$SQL::command_ref);
	    if("@command" =~ /^[^ \t\n=]*\257</) {
		# Replacement string is (part of) the command (and not just
		# argument or variable definition V1={})
		# E.g. parallel {}, parallel my_{= s/_//=}, parallel {2}
		# Do no quote (Otherwise it will fail if the input contains spaces)
		$Global::noquote = 1;
	    }
	}

	my $cmd_line = CommandLine->new($self->seq(),
					$self->{'command'},
					$self->{'arg_queue'},
					$self->{'context_replace'},
					$self->{'max_number_of_args'},
					$self->{'transfer_files'},
					$self->{'return_files'},
					$self->{'replacecount'},
					$self->{'len'},
	    );
	$cmd_line->populate();
	::debug("init","cmd_line->number_of_args ",
		$cmd_line->number_of_args(), "\n");
	if(not $Global::no_more_input and ($opt::pipe or $opt::pipepart)) {
	    if($cmd_line->replaced() eq "") {
		# Empty command - pipe requires a command
		::error("--pipe/--pipepart must have a command to pipe into ".
			"(e.g. 'cat').");
		::wait_and_exit(255);
	    }
	} else {
	    if($cmd_line->number_of_args() == 0) {
		# We did not get more args - maybe at EOF string?
		return undef;
	    } elsif($cmd_line->replaced() eq "") {
		# Empty command - get the next instead
		return $self->get();
	    }
	}
	$self->set_seq($self->seq()+1);
	return $cmd_line;
    }
}

sub unget {
    my $self = shift;
    unshift @{$self->{'unget'}}, @_;
}

sub empty {
    my $self = shift;
    my $empty = (not @{$self->{'unget'}}) && $self->{'arg_queue'}->empty();
    ::debug("run", "CommandLineQueue->empty $empty");
    return $empty;
}

sub seq {
    my $self = shift;
    return $self->{'seq'};
}

sub set_seq {
    my $self = shift;
    $self->{'seq'} = shift;
}

sub quote_args {
    my $self = shift;
    # If there is not command emulate |bash
    return $self->{'command'};
}


package Limits::Command;

# Maximal command line length (for -m and -X)
sub max_length {
    # Find the max_length of a command line and cache it
    # Returns:
    #   number of chars on the longest command line allowed
    if(not $Limits::Command::line_max_len) {
	# Disk cache of max command line length
	my $len_cache = $Global::cache_dir . "/tmp/sshlogin/" . ::hostname() .
	    "/linelen";
	my $cached_limit;
	if(-e $len_cache) {
	    open(my $fh, "<", $len_cache) || ::die_bug("Cannot read $len_cache");
	    $cached_limit = <$fh>;
	    close $fh;
	} else {
	    $cached_limit = real_max_length();
	    # If $HOME is write protected: Do not fail
	    my $dir = ::dirname($len_cache);
	    -d $dir or eval { File::Path::mkpath($dir); };
	    open(my $fh, ">", $len_cache);
	    print $fh $cached_limit;
	    close $fh;
	}
	$Limits::Command::line_max_len = tmux_length($cached_limit);
	if($opt::max_chars) {
	    if($opt::max_chars <= $cached_limit) {
		$Limits::Command::line_max_len = $opt::max_chars;
	    } else {
		::warning("Value for -s option should be < $cached_limit.");
	    }
	}
    }
    return int($Limits::Command::line_max_len);
}

sub real_max_length {
    # Find the max_length of a command line
    # Returns:
    #   The maximal command line length
    # Use an upper bound of 8 MB if the shell allows for infinite long lengths
    my $upper = 8_000_000;
    my $len = 8;
    do {
	if($len > $upper) { return $len };
	$len *= 16;
    } while (is_acceptable_command_line_length($len));
    # Then search for the actual max length between 0 and upper bound
    return binary_find_max_length(int($len/16),$len);
}

sub binary_find_max_length {
    # Given a lower and upper bound find the max_length of a command line
    # Returns:
    #   number of chars on the longest command line allowed
    my ($lower, $upper) = (@_);
    if($lower == $upper or $lower == $upper-1) { return $lower; }
    my $middle = int (($upper-$lower)/2 + $lower);
    ::debug("init", "Maxlen: $lower,$upper,$middle : ");
    if (is_acceptable_command_line_length($middle)) {
	return binary_find_max_length($middle,$upper);
    } else {
	return binary_find_max_length($lower,$middle);
    }
}

sub is_acceptable_command_line_length {
    # Test if a command line of this length can run
    # in the current environment
    # Returns:
    #   0 if the command line length is too long
    #   1 otherwise
    my $len = shift;
    if($ENV{PARALLEL_ENV}) {
	$len += length $ENV{PARALLEL_ENV} + (-s $ENV{PARALLEL_ENV})*2;
    }
    ::qqx("true "."x"x$len);
    ::debug("init", "$len=$? ");
    return not $?;
}

sub tmux_length {
    # If $opt::tmux set, find the limit for tmux
    # tmux 1.8 has a 2kB limit
    # tmux 1.9 has a 16kB limit
    # tmux 2.0 has a 16kB limit
    # tmux 2.1 has a 16kB limit
    # tmux 2.2 has a 16kB limit
    # Input:
    #   $len = maximal command line length
    # Returns:
    #   $tmux_len = maximal length runable in tmux
    local $/ = "\n";
    my $len = shift;
    if($opt::tmux) {
	$ENV{'PARALLEL_TMUX'} ||= "tmux";
	if(not ::which($ENV{'PARALLEL_TMUX'})) {
	    ::error($ENV{'PARALLEL_TMUX'}." not found in \$PATH.");
	    ::wait_and_exit(255);
	}
	my @out;
	for my $l (1, 2020, 16320, 100000, $len) {
	    my $tmpfile = ::tmpname("tms");
	    my $tmuxcmd = $ENV{'PARALLEL_TMUX'}.
		" -S $tmpfile new-session -d -n echo $l".
		("x"x$l). " && echo $l; rm -f $tmpfile";
	    push @out, ::qqx($tmuxcmd);
	    ::rm($tmpfile);
	}
	::debug("tmux","tmux-out ",@out);
	chomp @out;
	# The arguments is given 3 times on the command line
	# and the wrapping is around 30 chars
	# (29 for tmux1.9, 33 for tmux1.8)
	my $tmux_len = (::max(@out));
	$len = ::min($len,int($tmux_len/4-33));
	::debug("tmux","tmux-length ",$len);
    }
    return $len;
}


package RecordQueue;

sub new {
    my $class = shift;
    my $fhs = shift;
    my $colsep = shift;
    my @unget = ();
    my $arg_sub_queue;
    if($opt::sqlworker) {
	# Open SQL table
	$arg_sub_queue = SQLRecordQueue->new();
    } elsif(defined $colsep) {
	# Open one file with colsep
	$arg_sub_queue = RecordColQueue->new($fhs);
    } else {
	# Open one or more files if multiple -a
	$arg_sub_queue = MultifileQueue->new($fhs);
    }
    return bless {
	'unget' => \@unget,
	'arg_number' => 0,
	'arg_sub_queue' => $arg_sub_queue,
    }, ref($class) || $class;
}

sub get {
    # Returns:
    #   reference to array of Arg-objects
    my $self = shift;
    if(@{$self->{'unget'}}) {
	$self->{'arg_number'}++;
	# Flush cached computed replacements in Arg-objects
	# To fix: parallel --bar echo {%} ::: a b c ::: d e f
	my $ret = shift @{$self->{'unget'}};
	if($ret) {
	    map { $_->flush_cache() } @$ret;
	}
	return $ret;
    }
    my $ret = $self->{'arg_sub_queue'}->get();
    if($ret and
       grep { index($_->orig(),"\0") > 0 } @$ret) {
	# Allow for \0 in position 0 because GNU Parallel uses "\0"
	# to mean no-string
	::warning("a NUL character occurred in the input.",
		  "It cannot be passed through in the argument list.",
		  "Did you mean to use the --null option?");
    }
    if(defined $Global::max_number_of_args
       and $Global::max_number_of_args == 0) {
	::debug("run", "Read 1 but return 0 args\n");
	# \0 => nothing (not the empty string)
	$ret = [Arg->new("\0")];
    } else {
	# Flush cached computed replacements in Arg-objects
	# To fix: parallel --bar echo {%} ::: a b c ::: d e f
	if($ret) {
	    map { $_->flush_cache() } @$ret;
	}
    }
    return $ret;
}

sub unget {
    my $self = shift;
    ::debug("run", "RecordQueue-unget '@_'\n");
    $self->{'arg_number'} -= @_;
    unshift @{$self->{'unget'}}, @_;
}

sub empty {
    my $self = shift;
    my $empty = not @{$self->{'unget'}};
    $empty &&= $self->{'arg_sub_queue'}->empty();
    ::debug("run", "RecordQueue->empty $empty");
    return $empty;
}

sub arg_number {
    my $self = shift;
    return $self->{'arg_number'};
}


package RecordColQueue;

sub new {
    my $class = shift;
    my $fhs = shift;
    my @unget = ();
    my $arg_sub_queue = MultifileQueue->new($fhs);
    return bless {
	'unget' => \@unget,
	'arg_sub_queue' => $arg_sub_queue,
    }, ref($class) || $class;
}

sub get {
    # Returns:
    #   reference to array of Arg-objects
    my $self = shift;
    if(@{$self->{'unget'}}) {
	return shift @{$self->{'unget'}};
    }
    my $unget_ref = $self->{'unget'};
    if($self->{'arg_sub_queue'}->empty()) {
	return undef;
    }
    my $in_record = $self->{'arg_sub_queue'}->get();
    if(defined $in_record) {
	my @out_record = ();
	for my $arg (@$in_record) {
	    ::debug("run", "RecordColQueue::arg $arg\n");
	    my $line = $arg->orig();
	    ::debug("run", "line='$line'\n");
	    if($line ne "") {
		for my $s (split /$opt::colsep/o, $line, -1) {
		    push @out_record, Arg->new($s);
		}
	    } else {
		push @out_record, Arg->new("");
	    }
	}
	return \@out_record;
    } else {
	return undef;
    }
}

sub unget {
    my $self = shift;
    ::debug("run", "RecordColQueue-unget '@_'\n");
    unshift @{$self->{'unget'}}, @_;
}

sub empty {
    my $self = shift;
    my $empty = (not @{$self->{'unget'}} and
		 $self->{'arg_sub_queue'}->empty());
    ::debug("run", "RecordColQueue->empty $empty");
    return $empty;
}


package SQLRecordQueue;

sub new {
    my $class = shift;
    my @unget = ();
    return bless {
	'unget' => \@unget,
    }, ref($class) || $class;
}

sub get {
    # Returns:
    #   reference to array of Arg-objects
    my $self = shift;
    if(@{$self->{'unget'}}) {
	return shift @{$self->{'unget'}};
    }
    return $Global::sql->get_record();
}

sub unget {
    my $self = shift;
    ::debug("run", "SQLRecordQueue-unget '@_'\n");
    unshift @{$self->{'unget'}}, @_;
}

sub empty {
    my $self = shift;
    if(@{$self->{'unget'}}) { return 0; }
    my $get = $self->get();
    if(defined $get) {
	$self->unget($get);
    }
    my $empty = not $get;
    ::debug("run", "SQLRecordQueue->empty $empty");
    return $empty;
}


package MultifileQueue;

@Global::unget_argv=();

sub new {
    my $class = shift;
    my $fhs = shift;
    for my $fh (@$fhs) {
	if(-t $fh and -t ($Global::status_fd || *STDERR)) {
	    ::warning("Input is read from the terminal. You either know what you",
		      "are doing (in which case: YOU ARE AWESOME!) or you forgot",
		      "::: or :::: or to pipe data into parallel. If so",
		      "consider going through the tutorial: man parallel_tutorial",
		      "Press CTRL-D to exit.");
	}
    }
    return bless {
	'unget' => \@Global::unget_argv,
	'fhs' => $fhs,
	'arg_matrix' => undef,
    }, ref($class) || $class;
}

sub get {
    my $self = shift;
    if($opt::link) {
	return $self->link_get();
    } else {
	return $self->nest_get();
    }
}

sub unget {
    my $self = shift;
    ::debug("run", "MultifileQueue-unget '@_'\n");
    unshift @{$self->{'unget'}}, @_;
}

sub empty {
    my $self = shift;
    my $empty = (not @Global::unget_argv
		 and not @{$self->{'unget'}});
    for my $fh (@{$self->{'fhs'}}) {
	$empty &&= eof($fh);
    }
    ::debug("run", "MultifileQueue->empty $empty ");
    return $empty;
}

sub link_get {
    my $self = shift;
    if(@{$self->{'unget'}}) {
	return shift @{$self->{'unget'}};
    }
    my @record = ();
    my $prepend;
    my $empty = 1;
    for my $fh (@{$self->{'fhs'}}) {
	my $arg = read_arg_from_fh($fh);
	if(defined $arg) {
	    # Record $arg for recycling at end of file
	    push @{$self->{'arg_matrix'}{$fh}}, $arg;
	    push @record, $arg;
	    $empty = 0;
	} else {
	    ::debug("run", "EOA ");
	    # End of file: Recycle arguments
	    push @{$self->{'arg_matrix'}{$fh}}, shift @{$self->{'arg_matrix'}{$fh}};
	    # return last @{$args->{'args'}{$fh}};
	    push @record, @{$self->{'arg_matrix'}{$fh}}[-1];
	}
    }
    if($empty) {
	return undef;
    } else {
	return \@record;
    }
}

sub nest_get {
    my $self = shift;
    if(@{$self->{'unget'}}) {
	return shift @{$self->{'unget'}};
    }
    my @record = ();
    my $prepend;
    my $empty = 1;
    my $no_of_inputsources = $#{$self->{'fhs'}} + 1;
    if(not $self->{'arg_matrix'}) {
	# Initialize @arg_matrix with one arg from each file
	# read one line from each file
	my @first_arg_set;
	my $all_empty = 1;
	for (my $fhno = 0; $fhno < $no_of_inputsources ; $fhno++) {
	    my $arg = read_arg_from_fh($self->{'fhs'}[$fhno]);
	    if(defined $arg) {
		$all_empty = 0;
	    }
	    $self->{'arg_matrix'}[$fhno][0] = $arg || Arg->new("");
	    push @first_arg_set, $self->{'arg_matrix'}[$fhno][0];
	}
	if($all_empty) {
	    # All filehandles were at eof or eof-string
	    return undef;
	}
	return [@first_arg_set];
    }

    # Treat the case with one input source special.  For multiple
    # input sources we need to remember all previously read values to
    # generate all combinations. But for one input source we can
    # forget the value after first use.
    if($no_of_inputsources == 1) {
	my $arg = read_arg_from_fh($self->{'fhs'}[0]);
	if(defined($arg)) {
	    return [$arg];
	}
	return undef;
    }
    for (my $fhno = $no_of_inputsources - 1; $fhno >= 0; $fhno--) {
	if(eof($self->{'fhs'}[$fhno])) {
	    next;
	} else {
	    # read one
	    my $arg = read_arg_from_fh($self->{'fhs'}[$fhno]);
	    defined($arg) || next; # If we just read an EOF string: Treat this as EOF
	    my $len = $#{$self->{'arg_matrix'}[$fhno]} + 1;
	    $self->{'arg_matrix'}[$fhno][$len] = $arg;
	    # make all new combinations
	    my @combarg = ();
	    for (my $fhn = 0; $fhn < $no_of_inputsources; $fhn++) {
		push(@combarg, [0, $#{$self->{'arg_matrix'}[$fhn]}],
		     # Is input source --link'ed to the next?
		     $opt::linkinputsource[$fhn+1]);
	    }
	    # Find only combinations with this new entry
	    $combarg[2*$fhno] = [$len,$len];
	    # map combinations
	    # [ 1, 3, 7 ], [ 2, 4, 1 ]
	    # =>
	    # [ m[0][1], m[1][3], m[2][7] ], [ m[0][2], m[1][4], m[2][1] ]
	    my @mapped;
	    for my $c (expand_combinations(@combarg)) {
		my @a;
		for my $n (0 .. $no_of_inputsources - 1 ) {
		    push @a,  $self->{'arg_matrix'}[$n][$$c[$n]];
		}
		push @mapped, \@a;
	    }
	    # append the mapped to the ungotten arguments
	    push @{$self->{'unget'}}, @mapped;
	    # get the first
	    if(@mapped) {
		return shift @{$self->{'unget'}};
	    }
	}
    }
    # all are eof or at EOF string; return from the unget queue
    return shift @{$self->{'unget'}};
}

sub read_arg_from_fh {
    # Read one Arg from filehandle
    # Returns:
    #   Arg-object with one read line
    #   undef if end of file
    my $fh = shift;
    my $prepend;
    my $arg;
    do {{
	# This makes 10% faster
	if(not ($arg = <$fh>)) {
	    if(defined $prepend) {
		return Arg->new($prepend);
	    } else {
		return undef;
	    }
	}
	# Remove delimiter
	chomp $arg;
	if($Global::end_of_file_string and
	   $arg eq $Global::end_of_file_string) {
	    # Ignore the rest of input file
	    close $fh;
	    ::debug("run", "EOF-string ($arg) met\n");
	    if(defined $prepend) {
		return Arg->new($prepend);
	    } else {
		return undef;
	    }
	}
	if(defined $prepend) {
	    $arg = $prepend.$arg; # For line continuation
	    undef $prepend;
	}
	if($Global::ignore_empty) {
	    if($arg =~ /^\s*$/) {
		redo; # Try the next line
	    }
	}
	if($Global::max_lines) {
	    if($arg =~ /\s$/) {
		# Trailing space => continued on next line
		$prepend = $arg;
		redo;
	    }
	}
    }} while (1 == 0); # Dummy loop {{}} for redo
    if(defined $arg) {
	return Arg->new($arg);
    } else {
	::die_bug("multiread arg undefined");
    }
}

sub expand_combinations {
    # Input:
    #   ([xmin,xmax], [ymin,ymax], ...)
    # Returns: ([x,y,...],[x,y,...])
    # where xmin <= x <= xmax and ymin <= y <= ymax
    my $minmax_ref = shift;
    my $link = shift; # This is linked to the next input source
    my $xmin = $$minmax_ref[0];
    my $xmax = $$minmax_ref[1];
    my @p;
    if(@_) {
	my @rest = expand_combinations(@_);
	if($link) {
	    # Linked to next col with --link/:::+/::::+
	    # TODO BUG does not wrap values if not same number of vals
	    push(@p, map { [$$_[0], @$_] }
		 grep { $xmin <= $$_[0] and $$_[0] <= $xmax } @rest);
	} else {
	    # If there are more columns: Compute those recursively
	    for(my $x = $xmin; $x <= $xmax; $x++) {
		push @p, map { [$x, @$_] } @rest;
	    }
	}
    } else {
	for(my $x = $xmin; $x <= $xmax; $x++) {
	    push @p, [$x];
	}
    }
    return @p;
}


package Arg;

sub new {
    my $class = shift;
    my $orig = shift;
    my @hostgroups;
    if($opt::hostgroups) {
	if($orig =~ s:@(.+)::) {
	    # We found hostgroups on the arg
	    @hostgroups = split(/\+/, $1);
	    if(not grep { defined $Global::hostgroups{$_} } @hostgroups) {
		::warning("No such hostgroup (@hostgroups).");
		@hostgroups = (keys %Global::hostgroups);
	    }
        } else {
	    @hostgroups = (keys %Global::hostgroups);
	}
    }
    return bless {
	'orig' => $orig,
	'hostgroups' => \@hostgroups,
    }, ref($class) || $class;
}

sub Q {
    # Q alias for ::shell_quote_scalar
    # Run shell_quote_scalar once to set the reference to the sub
    my $a = ::shell_quote_scalar(@_);
    *Q = \&::shell_quote_scalar;
    return $a;
}

sub pQ {
    # pQ alias for ::perl_quote_scalar
    *pQ = \&::perl_quote_scalar;
    return pQ(@_);
}

sub total_jobs {
    return $Global::JobQueue->total_jobs();
}

{
    my %perleval;
    my $job;
    sub skip {
	# shorthand for $job->skip();
	$job->skip();
    }
    sub slot {
	# shorthand for $job->slot();
	$job->slot();
    }
    sub seq {
	# shorthand for $job->seq();
	$job->seq();
    }

    sub replace {
	# Calculates the corresponding value for a given perl expression
	# Returns:
	#   The calculated string (quoted if asked for)
	my $self = shift;
	my $perlexpr = shift; # E.g. $_=$_ or s/.gz//
	my $quote = (shift) ? 1 : 0; # should the string be quoted?
	# This is actually a CommandLine-object,
	# but it looks nice to be able to say {= $job->slot() =}
	$job = shift;
	$perlexpr =~ s/^(-?\d+)? *//; # Positional replace treated as normal replace
	if(not $self->{'cache'}{$perlexpr}) {
	    # Only compute the value once
	    # Use $_ as the variable to change
	    local $_;
	    if($Global::trim eq "n") {
		$_ = $self->{'orig'};
	    } else {
		# Trim the input
		$_ = trim_of($self->{'orig'});
	    }
	    ::debug("replace", "eval ", $perlexpr, " ", $_, "\n");
	    if(not $perleval{$perlexpr}) {
		# Make an anonymous function of the $perlexpr
		# And more importantly: Compile it only once
		if($perleval{$perlexpr} =
		   eval('sub { no strict; no warnings; my $job = shift; '.
			$perlexpr.' }')) {
		    # All is good
		} else {
		    # The eval failed. Maybe $perlexpr is invalid perl?
		    ::error("Cannot use $perlexpr: $@");
		    ::wait_and_exit(255);
		}
	    }
	    # Execute the function
	    $perleval{$perlexpr}->($job);
	    $self->{'cache'}{$perlexpr} = $_;
	}
	# Return the value quoted if needed
	return($quote ? ::shell_quote_scalar($self->{'cache'}{$perlexpr})
	       : $self->{'cache'}{$perlexpr});
    }
}

sub flush_cache {
    # Flush cache of computed values
    my $self = shift;
    $self->{'cache'} = undef;
}

sub orig {
    my $self = shift;
    return $self->{'orig'};
}

sub trim_of {
    # Removes white space as specifed by --trim:
    # n = nothing
    # l = start
    # r = end
    # lr|rl = both
    # Returns:
    #   string with white space removed as needed
    my @strings = map { defined $_ ? $_ : "" } (@_);
    my $arg;
    if($Global::trim eq "n") {
	# skip
    } elsif($Global::trim eq "l") {
	for my $arg (@strings) { $arg =~ s/^\s+//; }
    } elsif($Global::trim eq "r") {
	for my $arg (@strings) { $arg =~ s/\s+$//; }
    } elsif($Global::trim eq "rl" or $Global::trim eq "lr") {
	for my $arg (@strings) { $arg =~ s/^\s+//; $arg =~ s/\s+$//; }
    } else {
	::error("--trim must be one of: r l rl lr.");
	::wait_and_exit(255);
    }
    return wantarray ? @strings : "@strings";
}


package TimeoutQueue;

sub new {
    my $class = shift;
    my $delta_time = shift;
    my ($pct);
    if($delta_time =~ /(\d+(\.\d+)?)%/) {
	# Timeout in percent
	$pct = $1/100;
	$delta_time = 1_000_000;
    }
    if($delta_time =~ /[dhms]/i) {
	$delta_time =~ s/s/*1+/gi;
	$delta_time =~ s/m/*60+/gi;
	$delta_time =~ s/h/*3600+/gi;
	$delta_time =~ s/d/*86400+/gi;
	$delta_time = eval $delta_time."0";
    }
    return bless {
	'queue' => [],
	'delta_time' => $delta_time,
	'pct' => $pct,
	'remedian_idx' => 0,
	'remedian_arr' => [],
	'remedian' => undef,
    }, ref($class) || $class;
}

sub delta_time {
    my $self = shift;
    return $self->{'delta_time'};
}

sub set_delta_time {
    my $self = shift;
    $self->{'delta_time'} = shift;
}

sub remedian {
    my $self = shift;
    return $self->{'remedian'};
}

sub set_remedian {
    # Set median of the last 999^3 (=997002999) values using Remedian
    #
    # Rousseeuw, Peter J., and Gilbert W. Bassett Jr. "The remedian: A
    # robust averaging method for large data sets." Journal of the
    # American Statistical Association 85.409 (1990): 97-104.
    my $self = shift;
    my $val = shift;
    my $i = $self->{'remedian_idx'}++;
    my $rref = $self->{'remedian_arr'};
    $rref->[0][$i%999] = $val;
    $rref->[1][$i/999%999] = (sort @{$rref->[0]})[$#{$rref->[0]}/2];
    $rref->[2][$i/999/999%999] = (sort @{$rref->[1]})[$#{$rref->[1]}/2];
    $self->{'remedian'} = (sort @{$rref->[2]})[$#{$rref->[2]}/2];
}

sub update_median_runtime {
    # Update delta_time based on runtime of finished job if timeout is
    # a percentage
    my $self = shift;
    my $runtime = shift;
    if($self->{'pct'}) {
	$self->set_remedian($runtime);
	$self->{'delta_time'} = $self->{'pct'} * $self->remedian();
	::debug("run", "Timeout: $self->{'delta_time'}s ");
    }
}

sub process_timeouts {
    # Check if there was a timeout
    my $self = shift;
    # $self->{'queue'} is sorted by start time
    while (@{$self->{'queue'}}) {
	my $job = $self->{'queue'}[0];
	if($job->endtime()) {
	    # Job already finished. No need to timeout the job
	    # This could be because of --keep-order
	    shift @{$self->{'queue'}};
	} elsif($job->is_timedout($self->{'delta_time'})) {
	    # Need to shift off queue before kill
	    # because kill calls usleep that calls process_timeouts
	    shift @{$self->{'queue'}};
	    $job->kill();
	} else {
	    # Because they are sorted by start time the rest are later
	    last;
	}
    }
}

sub insert {
    my $self = shift;
    my $in = shift;
    push @{$self->{'queue'}}, $in;
}


package SQL;

sub new {
    my $class = shift;
    my $dburl = shift;
    $Global::use{"DBI"} ||= eval "use DBI; 1;";
    # +DBURL = append to this DBURL
    my $append = $dburl=~s/^\+//;
    my %options = parse_dburl(get_alias($dburl));
    my %driveralias = ("sqlite" => "SQLite",
		       "sqlite3" => "SQLite",
		       "pg" => "Pg",
		       "postgres" => "Pg",
		       "postgresql" => "Pg",
		       "csv" => "CSV",
		       "oracle" => "Oracle",
		       "ora" => "Oracle");
    my $driver = $driveralias{$options{'databasedriver'}} ||
	$options{'databasedriver'};
    my $database = $options{'database'};
    my $host = $options{'host'} ? ";host=".$options{'host'} : "";
    my $port = $options{'port'} ? ";port=".$options{'port'} : "";
    my $dsn = "DBI:$driver:dbname=$database$host$port";
    my $userid = $options{'user'};
    my $password = $options{'password'};;
    my $dbh = DBI->connect($dsn, $userid, $password,
			   { RaiseError => 1, AutoInactiveDestroy => 1 })
	or die $DBI::errstr;
    $dbh->{'PrintWarn'} = $Global::debug || 0;
    $dbh->{'PrintError'} = $Global::debug || 0;
    $dbh->{'RaiseError'} = 1;
    $dbh->{'ShowErrorStatement'} = 1;
    $dbh->{'HandleError'} = sub {};

    if(not defined $options{'table'}) {
	::error("The DBURL ($dburl) must contain a table.");
	::wait_and_exit(255);
    }

    return bless {
	'dbh' => $dbh,
	'driver' => $driver,
	'max_number_of_args' => undef,
	'table' => $options{'table'},
	'append' => $append,
    }, ref($class) || $class;
}

sub get_alias {
    my $alias = shift;
    $alias =~ s/^(sql:)*//; # Accept aliases prepended with sql:
    if ($alias !~ /^:/) {
	return $alias;
    }

    # Find the alias
    my $path;
    if (-l $0) {
	($path) = readlink($0) =~ m|^(.*)/|;
    } else {
	($path) = $0 =~ m|^(.*)/|;
    }

    my @deprecated = ("$ENV{HOME}/.dburl.aliases",
		      "$path/dburl.aliases", "$path/dburl.aliases.dist");
    for (@deprecated) {
	if(-r $_) {
	    ::warning("$_ is deprecated. ".
		      "Use .sql/aliases instead (read man sql).");
	}
    }
    my @urlalias=();
    check_permissions("$ENV{HOME}/.sql/aliases");
    check_permissions("$ENV{HOME}/.dburl.aliases");
    my @search = ("$ENV{HOME}/.sql/aliases",
		  "$ENV{HOME}/.dburl.aliases", "/etc/sql/aliases",
		  "$path/dburl.aliases", "$path/dburl.aliases.dist");
    for my $alias_file (@search) {
	# local $/ needed if -0 set
	local $/ = "\n";
	if(-r $alias_file) {
	    open(my $in, "<", $alias_file) || die;
	    push @urlalias, <$in>;
	    close $in;
	}
    }
    my ($alias_part,$rest) = $alias=~/(:\w*)(.*)/;
    # If we saw this before: we have an alias loop
    if(grep {$_ eq $alias_part } @Private::seen_aliases) {
	::error("$alias_part is a cyclic alias.");
	exit -1;
    } else {
	push @Private::seen_aliases, $alias_part;
    }

    my $dburl;
    for (@urlalias) {
	/^$alias_part\s+(\S+.*)/ and do { $dburl = $1; last; }
    }

    if($dburl) {
	return get_alias($dburl.$rest);
    } else {
	::error("$alias is not defined in @search");
	exit(-1);
    }
}

sub check_permissions {
    my $file = shift;

    if(-e $file) {
	if(not -o $file) {
	    my $username = (getpwuid($<))[0];
	    ::warning("$file should be owned by $username: ".
		      "chown $username $file");
	}
	my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
	    $atime,$mtime,$ctime,$blksize,$blocks) = stat($file);
	if($mode & 077) {
	    my $username = (getpwuid($<))[0];
	    ::warning("$file should be only be readable by $username: ".
		      "chmod 600 $file");
	}
    }
}

sub parse_dburl {
    my $url = shift;
    my %options = ();
    # sql:mysql://[[user][:password]@][host][:port]/[database[/table][?query]]

    if($url=~m!(?:sql:)? # You can prefix with 'sql:'
               ((?:oracle|ora|mysql|pg|postgres|postgresql)(?:s|ssl|)|
                 (?:sqlite|sqlite2|sqlite3|csv)):// # Databasedriver ($1)
               (?:
                ([^:@/][^:@]*|) # Username ($2)
                (?:
                 :([^@]*) # Password ($3)
                )?
               @)?
               ([^:/]*)? # Hostname ($4)
               (?:
                :
                ([^/]*)? # Port ($5)
               )?
               (?:
                /
                ([^/?]*)? # Database ($6)
               )?
               (?:
                /
                ([^?]*)? # Table ($7)
               )?
               (?:
                \?
                (.*)? # Query ($8)
               )?
              !ix) {
	$options{databasedriver} = ::undef_if_empty(lc(uri_unescape($1)));
	$options{user} = ::undef_if_empty(uri_unescape($2));
	$options{password} = ::undef_if_empty(uri_unescape($3));
	$options{host} = ::undef_if_empty(uri_unescape($4));
	$options{port} = ::undef_if_empty(uri_unescape($5));
	$options{database} = ::undef_if_empty(uri_unescape($6));
	$options{table} = ::undef_if_empty(uri_unescape($7));
	$options{query} = ::undef_if_empty(uri_unescape($8));
	::debug("sql", "dburl $url\n");
	::debug("sql", "databasedriver ", $options{databasedriver},
		" user ", $options{user},
		" password ", $options{password}, " host ", $options{host},
		" port ", $options{port}, " database ", $options{database},
		" table ", $options{table}, " query ", $options{query}, "\n");
    } else {
	::error("$url is not a valid DBURL");
	exit 255;
    }
    return %options;
}

sub uri_unescape {
    # Copied from http://cpansearch.perl.org/src/GAAS/URI-1.55/URI/Escape.pm
    # to avoid depending on URI::Escape
    # This section is (C) Gisle Aas.
    # Note from RFC1630:  "Sequences which start with a percent sign
    # but are not followed by two hexadecimal characters are reserved
    # for future extension"
    my $str = shift;
    if (@_ && wantarray) {
	# not executed for the common case of a single argument
	my @str = ($str, @_);  # need to copy
	foreach (@str) {
	    s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
	}
	return @str;
    }
    $str =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg if defined $str;
    $str;
}

sub run {
    my $self = shift;
    my $stmt = shift;
    if($self->{'driver'} eq "CSV") {
	$stmt=~ s/;$//;
	if($stmt eq "BEGIN" or
	   $stmt eq "COMMIT") {
	    return undef;
	}
    }
    my @retval;
    my $dbh = $self->{'dbh'};
    ::debug("sql","$opt::sqlmaster$opt::sqlworker run $stmt\n");
    # Execute with the rest of the args - if any
    my $rv;
    my $sth;
    my $lockretry = 0;
    while($lockretry < 10) {
	$sth = $dbh->prepare($stmt);
	if($sth
	   and
	   eval { $rv = $sth->execute(@_) }) {
	    last;
	} else {
	    if($@ =~ /no such table|Table .* doesn.t exist|relation ".*" does not exist/
	       or
	       $DBI::errstr =~ /no such table|Table .* doesn.t exist|relation ".*" does not exist/) {
		# This is fine:
		# It is just a worker that reported back too late -
		# another worker had finished the job first
		# and the table was then dropped
		$rv = $sth = 0;
		last;
	    }
	    if($DBI::errstr =~ /locked/) {
		::debug("sql", "Lock retry: $lockretry");
		$lockretry++;
		::usleep(rand()*300);
	    } elsif(not $sth) {
		# Try again
		$lockretry++;
	    } else {
		::error($DBI::errstr);
		::wait_and_exit(255);
	    }
	}
    }
    if($lockretry >= 10) {
	::die_bug("retry > 10: $DBI::errstr");
    }
    if($rv < 0 and $DBI::errstr){
	::error($DBI::errstr);
	::wait_and_exit(255);
    }
    return $sth;
}

sub get {
    my $self = shift;
    my $sth = $self->run(@_);
    my @retval;
    # If $sth = 0 it means the table was dropped by another process
    while($sth) {
	my @row = $sth->fetchrow_array();
	@row or last;
	push @retval, \@row;
    }
    return \@retval;
}

sub table {
    my $self = shift;
    return $self->{'table'};
}

sub append {
    my $self = shift;
    return $self->{'append'};
}

sub update {
    my $self = shift;
    my $stmt = shift;
    my $table = $self->table();
    $self->run("UPDATE $table $stmt",@_);
}

sub output {
    my $self = shift;
    my $commandline = shift;

    $self->update("SET Stdout = ?, Stderr = ? WHERE Seq = ".
		  $commandline->seq(),
		  join("",@{$commandline->{'output'}{1}}),
		  join("",@{$commandline->{'output'}{2}}));
}

sub max_number_of_args {
    # Maximal number of args for this table
    my $self = shift;
    if(not $self->{'max_number_of_args'}) {
	# Read the number of args from the SQL table
	my $table = $self->table();
	my $v = $self->get("SELECT * FROM $table LIMIT 1;");
	my @reserved_columns = qw(Seq Host Starttime JobRuntime Send
	    Receive Exitval _Signal Command Stdout Stderr);
	if(not $v) {
	    ::error("$table contains no records");
	}
	# Count the number of Vx columns
	$self->{'max_number_of_args'} = $#{$v->[0]} - $#reserved_columns;
    }
    return $self->{'max_number_of_args'};
}

sub set_max_number_of_args {
    my $self = shift;
    $self->{'max_number_of_args'} = shift;
}

sub create_table {
    my $self = shift;
    if($self->append()) { return; }
    my $max_number_of_args = shift;
    $self->set_max_number_of_args($max_number_of_args);
    my $table = $self->table();
    $self->run(qq(DROP TABLE IF EXISTS $table;));
    # BIGINT and TEXT are not supported in these databases or are too small
    my %vartype = (
	"Oracle" => { "BIGINT" => "NUMBER(19,0)",
		      "TEXT" => "CLOB", },
	"mysql" => { "TEXT" => "LONGTEXT", },
	"CSV" => { "BIGINT" => "INT",
		   "FLOAT" => "REAL", },
	);
    my $BIGINT = $vartype{$self->{'driver'}}{"BIGINT"} || "BIGINT";
    my $TEXT = $vartype{$self->{'driver'}}{"TEXT"} || "TEXT";
    my $FLOAT = $vartype{$self->{'driver'}}{"FLOAT"} || "FLOAT(44)";
    my $v_def = join "", map { "V$_ $TEXT," } (1..$self->max_number_of_args());
    $self->run(qq{CREATE TABLE $table
		(Seq $BIGINT,
		 Host $TEXT,
		 Starttime $FLOAT,
		 JobRuntime $FLOAT,
		 Send $BIGINT,
		 Receive $BIGINT,
		 Exitval $BIGINT,
		 _Signal $BIGINT,
		 Command $TEXT,}.
	       $v_def.
	       qq{Stdout $TEXT,
		 Stderr $TEXT);});
}

sub insert_records {
    my $self = shift;
    my $seq = shift;
    my $command_ref = shift;
    my $record_ref = shift;
    my $table = $self->table();
    # For SQL encode the command with \257 space as split points
    my $command = join("\257 ",@$command_ref);
    my $v_cols = join ",", map { "V$_" } (1..$self->max_number_of_args());
    # Two extra value due to $seq, Exitval, Send
    my $v_vals = join ",", map { "?" } (1..$self->max_number_of_args()+4);
    $self->run("INSERT INTO $table (Seq,Command,Exitval,Send,$v_cols) ".
	       "VALUES ($v_vals);", $seq, $command, -1000,
	       0, @$record_ref[1..$#$record_ref]);
}

sub get_record {
    my $self = shift;
    my @retval;
    my $table = $self->table();
    my $v_cols = join ",", map { "V$_" } (1..$self->max_number_of_args());
    my $v = $self->get("SELECT Seq, Command, $v_cols FROM $table ".
		       "WHERE Exitval = -1000 ORDER BY Seq LIMIT 1;");
    if($v->[0]) {
	my $val_ref = $v->[0];
	# Mark record as taken
	my $seq = shift @$val_ref;
	# Save the sequence number to use when running the job
	$SQL::next_seq = $seq;
	$self->update("SET Exitval = ? WHERE Seq = ".$seq, -1220);
	my @command = split /\257 /, shift @$val_ref;
	$SQL::command_ref = \@command;
	for (@$val_ref) {
	    push @retval, Arg->new($_);
	}
    }
    if(@retval) {
	return \@retval;
    } else {
	return undef;
    }
}

sub total_jobs {
    my $self = shift;
    my $table = $self->table();
    my $v = $self->get("SELECT count(*) FROM $table;");
    if($v->[0]) {
	return $v->[0]->[0];
    } else {
	::die_bug("SQL::total_jobs");
    }
}

sub max_seq {
    my $self = shift;
    my $table = $self->table();
    my $v = $self->get("SELECT max(Seq) FROM $table;");
    if($v->[0]) {
	return $v->[0]->[0];
    } else {
	::die_bug("SQL::max_seq");
    }
}

sub finished {
    # Check if there are any jobs left in the SQL table that do not
    # have a "real" exitval
    my $self = shift;
    if($opt::wait or $Global::start_sqlworker) {
	my $table = $self->table();
	my $rv = $self->get("select Seq,Exitval from $table ".
			    "where Exitval <= -1000 limit 1");
	return not $rv->[0];
    } else {
	return 1;
    }
}

package Semaphore;

# This package provides a counting semaphore
#
# If a process dies without releasing the semaphore the next process
# that needs that entry will clean up dead semaphores
#
# The semaphores are stored in $PARALLEL_HOME/semaphores/id-<name> Each
# file in $PARALLEL_HOME/semaphores/id-<name>/ is the process ID of the
# process holding the entry. If the process dies, the entry can be
# taken by another process.

sub new {
    my $class = shift;
    my $id = shift;
    my $count = shift;
    $id =~ s/([^-_a-z0-9])/unpack("H*",$1)/ige; # Convert non-word chars to hex
    $id = "id-".$id; # To distinguish it from a process id
    my $parallel_locks = $Global::cache_dir . "/semaphores";
    -d $parallel_locks or ::mkdir_or_die($parallel_locks);
    my $lockdir = "$parallel_locks/$id";

    my $lockfile = $lockdir.".lock";
    if($count < 1) { ::die_bug("semaphore-count: $count"); }
    return bless {
	'lockfile' => $lockfile,
	'lockfh' => Symbol::gensym(),
	'lockdir' => $lockdir,
	'id' => $id,
	'idfile' => $lockdir."/".$id,
	'pid' => $$,
	'pidfile' => $lockdir."/".$$.'@'.::hostname(),
	'count' => $count + 1 # nlinks returns a link for the 'id-' as well
    }, ref($class) || $class;
}

sub remove_dead_locks {
    my $self = shift;
    my $lockdir = $self->{'lockdir'};

    for my $d (glob "$lockdir/*") {
	$d =~ m:$lockdir/([0-9]+)\@([-\._a-z0-9]+)$:o or next;
	my ($pid, $host) = ($1, $2);
	if($host eq ::hostname()) {
	    if(kill 0, $pid) {
		::debug("sem", "Alive: $pid $d\n");
	    } else {
		::debug("sem", "Dead: $d\n");
		::rm($d);
	    }
	}
    }
}

sub acquire {
    my $self = shift;
    my $sleep = 1; # 1 ms
    my $start_time = time;
    while(1) {
	# Can we get a lock?
	$self->atomic_link_if_count_less_than() and last;
	$self->remove_dead_locks();
	# Retry slower and slower up to 1 second
	$sleep = ($sleep < 1000) ? ($sleep * 1.1) : ($sleep);
	# Random to avoid every sleeping job waking up at the same time
	::usleep(rand()*$sleep);
	if($opt::semaphoretimeout) {
	    if($opt::semaphoretimeout > 0
	       and
	       time - $start_time > $opt::semaphoretimeout) {
		# Timeout: Take the semaphore anyway
		::warning("Semaphore timed out. Stealing the semaphore.");
		if(not -e $self->{'idfile'}) {
		    open (my $fh, ">", $self->{'idfile'}) or
			::die_bug("timeout_write_idfile: $self->{'idfile'}");
		    close $fh;
		}
		link $self->{'idfile'}, $self->{'pidfile'};
		last;
	    }
	    if($opt::semaphoretimeout < 0
	       and
	       time - $start_time > -$opt::semaphoretimeout) {
		# Timeout: Exit
		::warning("Semaphore timed out. Exiting.");
		exit(1);
		last;
	    }
	}
    }
    ::debug("sem", "acquired $self->{'pid'}\n");
}

sub release {
    my $self = shift;
    ::rm($self->{'pidfile'});
    if($self->nlinks() == 1) {
	# This is the last link, so atomic cleanup
	$self->lock();
	if($self->nlinks() == 1) {
	    ::rm($self->{'idfile'});
	    rmdir $self->{'lockdir'};
	}
	$self->unlock();
    }
    ::debug("run", "released $self->{'pid'}\n");
}

sub pid_change {
    # This should do what release()+acquire() would do without having
    # to re-acquire the semaphore
    my $self = shift;

    my $old_pidfile =  $self->{'pidfile'};
    $self->{'pid'} = $$;
    $self->{'pidfile'} = $self->{'lockdir'}."/".$$.'@'.::hostname();
    my $retval = link $self->{'idfile'}, $self->{'pidfile'};
    ::debug("sem","link($self->{'idfile'},$self->{'pidfile'})=$retval\n");
    ::rm($old_pidfile);
}

sub atomic_link_if_count_less_than {
    # Link $file1 to $file2 if nlinks to $file1 < $count
    my $self = shift;
    my $retval = 0;
    $self->lock();
    my $nlinks = $self->nlinks();
    ::debug("sem","$nlinks<$self->{'count'} ");
    if($nlinks < $self->{'count'}) {
	-d $self->{'lockdir'} or ::mkdir_or_die($self->{'lockdir'});
	if(not -e $self->{'idfile'}) {
	    open (my $fh, ">", $self->{'idfile'}) or
		::die_bug("write_idfile: $self->{'idfile'}");
	    close $fh;
	}
	$retval = link $self->{'idfile'}, $self->{'pidfile'};
	::debug("sem","link($self->{'idfile'},$self->{'pidfile'})=$retval\n");
    }
    $self->unlock();
    ::debug("sem", "atomic $retval");
    return $retval;
}

sub nlinks {
    my $self = shift;
    if(-e $self->{'idfile'}) {
	return (stat(_))[3];
    } else {
	return 0;
    }
}

sub lock {
    my $self = shift;
    my $sleep = 100; # 100 ms
    my $total_sleep = 0;
    $Global::use{"Fcntl"} ||= eval "use Fcntl qw(:DEFAULT :flock); 1;";
    my $locked = 0;
    while(not $locked) {
	if(tell($self->{'lockfh'}) == -1) {
	    # File not open
	    open($self->{'lockfh'}, ">", $self->{'lockfile'})
		or ::debug("run", "Cannot open $self->{'lockfile'}");
	}
	if($self->{'lockfh'}) {
	    # File is open
	    chmod 0666, $self->{'lockfile'}; # assuming you want it a+rw
	    if(flock($self->{'lockfh'}, LOCK_EX()|LOCK_NB())) {
		# The file is locked: No need to retry
		$locked = 1;
		last;
	    } else {
		if ($! =~ m/Function not implemented/) {
		    ::warning("flock: $!",
			      "Will wait for a random while.");
		    ::usleep(rand(5000));
		    # File cannot be locked: No need to retry
		    $locked = 2;
		    last;
		}
	    }
	}
	# Locking failed in first round
	# Sleep and try again
	$sleep = ($sleep < 1000) ? ($sleep * 1.1) : ($sleep);
	# Random to avoid every sleeping job waking up at the same time
	::usleep(rand()*$sleep);
	$total_sleep += $sleep;
	if($opt::semaphoretimeout) {
	    if($opt::semaphoretimeout > 0
	       and
	       $total_sleep/1000 > $opt::semaphoretimeout) {
		# Timeout: Take the semaphore anyway
		::warning("Semaphore timed out. Taking the semaphore.");
		$locked = 3;
		last;
	    }
	    if($opt::semaphoretimeout < 0
	       and
	       $total_sleep/1000 > -$opt::semaphoretimeout) {
		# Timeout: Exit
		::warning("Semaphore timed out. Exiting.");
		$locked = 4;
		last;
	    }
	} else {
	    if($total_sleep/1000 > 30) {
		::warning("Semaphore stuck for 30 seconds. ".
			  "Consider using --semaphoretimeout.");
	    }
	}
    }
    ::debug("run", "locked $self->{'lockfile'}");
}

sub unlock {
    my $self = shift;
    ::rm($self->{'lockfile'});
    close $self->{'lockfh'};
    ::debug("run", "unlocked\n");
}

# Keep perl -w happy

$opt::x = $Semaphore::timeout = $Semaphore::wait =
$Job::file_descriptor_warning_printed = $Global::envdef = @Arg::arg =
$Global::max_slot_number;