dd-status

#!/bin/bash
#
# dd-status - a dd wrapper with progress status
#
#    Copyright (C) 2013 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
#
#    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. See <http://www.gnu.org/licenses/gpl.html>

myname="${0##*/}"
time=30
block=1M

fatal()   { [[ "$1" ]] && echo "$myname: error: $1" >&2 ; exit ${2:-1} ; }
message() { printf "%s\n" "$1"; }
argerr()  { printf "%s: %s\n" "$myname" "${1:-error}" >&2 ; usage 1 ; }
integer() { [[ "$1" != *[!0-9]* ]] || argerr "'$1'${2:+ in $2} is not an integer." ; }
invalid() { argerr "invalid option: $1" ; }
missing() { argerr "missing ${2:+$2 }argument${1:+ from $1}." ; }

is_running() { kill -0 $pid 2>/dev/null ; }

usage() {
	cat <<-USAGE
	Usage: $myname [options] INPUT OUTPUT
	USAGE
	if [[ "$1" ]] ; then
		cat >&2 <<- USAGE
		Try '$myname --help' for more information.
		USAGE
		exit 1
	fi
	cat <<-USAGE

	dd wrapper with progress status

	Options:
	  -h|--help    - show this page.
	  -f|--force   - force copy even for mounted partitions

	  --time TIME  - display progress every TIME seconds. [Default: $time]
	  --block SIZE - copy SIZE blocks at a time. [Default: $block]

	Copyright (C) 2012 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
	License: GPLv3 or later. See <http://www.gnu.org/licenses/gpl.html>
	USAGE
	exit 0
}

# Option handling
files=()
for arg in "$@"; do [[ "$arg" == "-h" || "$arg" == "--help" ]] && usage ; done
while (( $# )); do
	case "$1" in
	-f|--force   ) force=1                        ;;
	--time       ) shift ; time="$1"              ;;
	--time=*     ) time="${1#*=}"                 ;;
	--block      ) shift ; block="$1"             ;;
	--block=*    ) block="${1#*=}"                ;;
	--           ) shift ; break                  ;;
	-*           ) invalid "$1"                   ;;
	*            ) files+=( "$1" )                ;;
	esac
	shift
done
files+=( "$@" )
input=${files[0]}
output=${files[1]}

[[ "$input"  ]] || missing "" "INPUT"
[[ "$output" ]] || missing "" "OUTPUT"
[[ "$block"  ]] || missing "--block" "SIZE"

integer "$time" "--time"

if ! ((force)); then
	for file in "$input" "$output"; do
		if [[ -b "$file" ]] && grep -q "^$file " /proc/mounts; then
			fatal "$file seems to be a mounted partition. Un-mount it first or use --force."
		fi
	done
fi

echo "dd if=\"$input\" of=\"$output\" bs=\"$block\""

#set -m  # do not supress backgound output
dd if="$input" of="$output" bs="$block" & pid=$!
trap 'pkill -P $$' EXIT  # abort dd if script it aborted
sleep 0.2  # wait for any immediate errors (permission denied, file not found, etc)

if is_running $pid; then
	echo "dd PID:	$pid"
	echo "Starting at $(date)"
	echo "Reporting every $time seconds"
	while is_running $pid; do
		sleep "$time"
		date
		kill -USR1 $pid 2>/dev/null   # request dd status report
	done
fi