diff --git a/README.md b/README.md
index fc431b8..8bf757f 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,11 @@ Configuration
 =============
 
 
-All the configuration is done in the file port-proxy.conf, which is readed from the current directory when starting port-proxy
+All the configuration is done in the file port-proxy.conf, which is readed from the current directory when starting port-proxy.
+
+It is possible to use environment variables in the configuration file. Any $WORD or ${WORD} will be replaced by the value of the environment variable WORD, provided that the variable exists.
+
+**NOTE**: There is currently no way to use the character "$" when it is followed by a word character or a "{".
 
 There are the following parameters which can apear multiple times:
 
@@ -117,6 +121,8 @@ perl port-proxy [-d] [-D] [-c conffile]
 -d	 Enable debug output
 -D	 Become a background process (detach don't work on windows)
 -c conffile	 Specify an config file
+-p PIDFILE  Create a file containing th PID plus commands to
+            to send a kill to the process and remove the pidfile
 ```
 
 **Example:**
diff --git a/src/port-proxy b/src/port-proxy
index 2614e41..452b343 100755
--- a/src/port-proxy
+++ b/src/port-proxy
@@ -24,10 +24,15 @@ my $detach=0; # detach (unix only)
 
 #-- options --
 my %opts;
-getopt('d:c:D',\%opts);
+getopts('dc:Dp:',\%opts);
 if (exists $opts{'d'}) { $debug=1; }
 if (exists $opts{'c'}) { $configFile=$opts{'c'}; }
 if (exists $opts{'D'}) { $detach=1; }
+# -p filename.pid will put
+# kill \
+# PID
+# rm filename.pid
+# into the file. Usefull for killing the daemon and removing the pidfile
 
 #---- Global Vars ---
 my @allow_proxy_to=();
@@ -172,22 +177,32 @@ sub ReadConfig()
     @allow_proxy_to=();
     open(F,"<$configFile") || die "can't open file $configFile\n";
     while(<F>) {
-	$line=$_;
-	$line=~s/#.*$//g; # remove comments
-	if ($debug) { print "Conf>$line"; }
-	if ( $line=~/^\s*(.+?)=(.*?)\s*$/) {
-	    $param=$1; $val=$2;
-	    if ($param eq 'forward') {
-		@aval=split(/ *, */,$val);
-		CreateListenSock($aval[0],$aval[1],$aval[2],$aval[3]);
-	    } elsif($param eq 'allow_proxy_to') {
-		push(@allow_proxy_to,$val)
-	    }
-	}
+		$line= $_;
+		$line=~ s/#.*$//g; # remove comments
+		$line=~ s/\$(\w+|\{\w+\})/envvar($1)/ge;
+		if ($debug) { print "Conf>$line"; }
+		if ( $line=~/^\s*(.+?)=(.*?)\s*$/) {
+			$param=$1; $val=$2;
+			if ($param eq 'forward') {
+				@aval=split(/ *, */,$val);
+				CreateListenSock($aval[0],$aval[1],$aval[2],$aval[3]);
+			} elsif($param eq 'allow_proxy_to') {
+				push(@allow_proxy_to,$val)
+			}
+		}
     }
     close(F);
 }
 
+sub envvar {
+	my($varname)= @_;
+	for ($varname) {
+		s/^\{//;
+		s/\}$//
+	}
+	return defined($ENV{$varname}) ? $ENV{$varname} : $_[0];
+}
+
 #---
 # Handle some (unix) signals; HUP: restart with reading config; TERM/KILL: shut down
 sub sigHandler($) # sigHandler(signame)
@@ -374,8 +389,15 @@ sub daemonize {
 	open STDIN, '/dev/null' or die "Can't read /dev/null: $!";
 	open STDOUT, '>/dev/null' or die "Can't write to /dev/null: $!";
 	defined(my $pid = fork) or die "Can't fork: $!";
-	exit if $pid;
-        setsid                  or die "Can't start a new session: $!";
-        open STDERR, '>&STDOUT' or die "Can't dup stdout: $!";
+	if ($pid) {
+		if ($opts{'p'}) {
+			open my $pidfile, '>', $opts{'p'} or exit;
+			print $pidfile "kill \\\n$pid\nrm ".$opts{'p'}."\n";
+			close $pidfile;
+		}
+		exit;
+	}
+	setsid                  or die "Can't start a new session: $!";
+	open STDERR, '>&STDOUT' or die "Can't dup stdout: $!";
 }