Implemented -X.

Fixed bug with -x:
  If the command line had more than one {} it could result in a too
  long line

parallel

@@ -28,7 +28,7 @@ command also invokes B<-f>.
 If B<command> is given, B<parallel> will behave similar to B<xargs>. If
 B<command> is not given B<parallel> will behave similar to B<cat | sh>.
 
-=item I<-0>
+=item B<-0>
 
 Use NUL as delimiter.  Normally input lines will end in \n
 (newline). If they end in \0 (NUL), then use this option. It is useful
@@ -56,13 +56,13 @@ B<-g> is the default. Can be reversed with B<-u>.
 
 Run N jobs in parallel.  0 means as many as possible. Default is 10.
 
-=item B<-j> +I<N>
+=item B<-j> I<+N>
 
 Add N to the number of CPUs.  Run this many jobs in parallel. For
 compute intensive jobs I<-j +0> is useful as it will run
 number-of-cpus jobs in parallel.
 
-=item B<-j> -I<N>
+=item B<-j> I<-N>
 
 Subtract N from the number of CPUs.  Run this many jobs in parallel.
 If the evaluated number is less than 1 then 1 will be used.
@@ -95,7 +95,14 @@ Verbose.  Print the job to be run. Can be reversed with B<-s>.
 
 =item B<-x>
 
-xargs.  Insert as many arguments as the command line length permits.
+xargs. Insert as many arguments as the command line length permits. If
+{} is not used the arguments will be appended to the line.  If {} is
+used multiple times each {} will be replaced with all the arguments.
+
+=item B<-X>
+
+xargs with context replace. This works like B<-x> except if {} is part
+of a word (like I<pic{}.jpg>) then the whole word will be repeated.
 
 =back
 
@@ -264,6 +271,7 @@ B<cat | sh> functionality is missing.
 Quoting in B<xargs> works like B<-q> in B<parallel>. Doing B<ls |
 parallel "wc {} >> B<{}.wc"> using B<xargs> seems to be impossible.
 
+
 =head1 BUGS
 
 Filenames beginning with '-' can cause some commands to give
@@ -322,7 +330,7 @@ use Getopt::Std;
 use strict;
 
 my ($processes,$command);
-getopts("0cdefgj:qsuvx") || die_usage();
+getopts("0cdefgj:qsuvxX") || die_usage();
 
 # Defaults:
 $Global::debug = 0;
@@ -339,6 +347,10 @@ if(defined $::opt_x) {
     $Global::xargs = 1; 
     $Global::command_line_max_len = max_length_of_command_line(); 
 }
+if(defined $::opt_X) { 
+    $Global::Xargs = 1; 
+    $Global::command_line_max_len = max_length_of_command_line(); 
+}
 if(defined $::opt_v) { $Global::verbose = 1; }
 if(defined $::opt_s) { $Global::verbose = 0; }
 if(defined $::opt_g) { $Global::grouped = 1; }
@@ -378,16 +390,40 @@ sub generate_command_line {
     my $command = shift;
     my ($job_line,$last_good);
     my ($next_arg,@quoted_args,$arg_length);
+    my ($number_of_substitution) = 1;
+    my ($length_of_context) = 0;
+    my ($length_of_command_no_args);
+    if($Global::xargs or $Global::Xargs) {
+	# Count number of {}'s on the command line
+	$number_of_substitution = ($command =~ s/{}/{}/g);
+	$number_of_substitution ||= 1;
+    }
+    if($Global::xargs) {
+	my $c = $command;
+	# remove all {}s
+	$c =~ s/{}//g;
+	$length_of_command_no_args = length($c);
+    }
+    if($Global::Xargs) {
+	my $c = $command;
+	while($c =~ s/(\S*{}\S*)//) {
+	    # Length of context minus the {}
+	    $length_of_context += length($1) - 2;
+	}
+	$length_of_command_no_args = length($c);
+    }
+
     while ($next_arg = get_next_arg()) {
 	push (@quoted_args, $next_arg);
-	if(not $Global::xargs) {
+	if(not $Global::xargs and not $Global::Xargs) {
 	    last;
 	} else {
-	    # Emulate xargs if there is a command and -x is set
+	    # Emulate xargs if there is a command and -x or -X is set
-	    $arg_length += length $next_arg + 1;
+	    $arg_length += $number_of_substitution * (1 + length ($next_arg)) 
-	    debug("arglen $arg_length\n");
+		+ $length_of_context;
-	    my $job_line_length = length($command) + 1 + $arg_length;
+	    # debug("arglen $arg_length = $number_of_substitution * (1 + length ($next_arg)) + $length_of_context\n");
-	    debug("linelen $job_line_length\n");
+	    my $job_line_length = $length_of_command_no_args + 1 + $arg_length;
+	    # debug("linelen $job_line_length = $length_of_command_no_args + 1 + $arg_length\n");
 	    if($job_line_length >= $Global::command_line_max_len) {
 		unget_arg(pop @quoted_args);
 		if($quoted_args[0]) {
@@ -399,12 +435,31 @@ sub generate_command_line {
 	}
     }
     if(@quoted_args) {
-	my $arg=join(" ",@quoted_args);
 	$job_line = $command;
-	if(defined $job_line and $job_line =~ s/{}/$arg/g) {
+	if(defined $job_line and $job_line =~/{}/) {
-	    # substituted {} with args
+	    # substitute {} with args
+	    if($Global::Xargs) {
+		# Context sensitive replace
+		while($job_line =~/{}/) {
+		    $job_line =~ /(\S*{}\S*)/ or die ("This should never happen"); 
+		    my $wordarg = $1;
+		    my @all_word_arg;
+		    for my $arg (@quoted_args) {
+			my $substituted = $wordarg;
+			$substituted=~s/{}/$arg/g;
+			push @all_word_arg, $substituted;
+		    }
+		    my $all_word_arg = join(" ",@all_word_arg);
+		    $job_line =~ s/$wordarg/$all_word_arg/;
+		}
+	    } else {
+		# Normal replace
+		my $arg=join(" ",@quoted_args);
+		$job_line =~ s/{}/$arg/g;
+	    }
 	} else {
 	    # append args
+	    my $arg=join(" ",@quoted_args);
 	    $job_line .= " $arg";
 	}
 	debug("Return jobline: $job_line\n");
@@ -905,5 +960,5 @@ sub my_dump {
 # Keep perl -w happy
 $main::opt_u = $main::opt_c = $main::opt_f = $main::opt_q =
 $main::opt_0 = $main::opt_s = $main::opt_v = $main::opt_g =
-$main::opt_j = $main::opt_d = $main::opt_x =1;
+$main::opt_j = $main::opt_d = $main::opt_x = $main::opt_X =1;
 $Global::xargs = 1;

parallel.1

@@ -124,7 +124,7 @@
 .\" ========================================================================
 .\"
 .IX Title "PARALLEL 1"
-.TH PARALLEL 1 "2009-03-12" "perl v5.10.0" "User Contributed Perl Documentation"
+.TH PARALLEL 1 "2009-03-16" "perl v5.10.0" "User Contributed Perl Documentation"
 .\" For nroff, turn off justification.  Always turn off hyphenation; it makes
 .\" way too many mistakes in technical documents.
 .if n .ad l
@@ -150,7 +150,7 @@ command also invokes \fB\-f\fR.
 .Sp
 If \fBcommand\fR is given, \fBparallel\fR will behave similar to \fBxargs\fR. If
 \&\fBcommand\fR is not given \fBparallel\fR will behave similar to \fBcat | sh\fR.
-.IP "\fI\-0\fR" 9
+.IP "\fB\-0\fR" 9
 .IX Item "-0"
 Use \s-1NUL\s0 as delimiter.  Normally input lines will end in \en
 (newline). If they end in \e0 (\s-1NUL\s0), then use this option. It is useful
@@ -173,12 +173,12 @@ printed when the command is finished. \s-1STDERR\s0 first followed by \s-1STDOUT
 .IP "\fB\-j\fR \fIN\fR" 9
 .IX Item "-j N"
 Run N jobs in parallel.  0 means as many as possible. Default is 10.
-.IP "\fB\-j\fR +\fIN\fR" 9
+.IP "\fB\-j\fR \fI+N\fR" 9
 .IX Item "-j +N"
 Add N to the number of CPUs.  Run this many jobs in parallel. For
 compute intensive jobs \fI\-j +0\fR is useful as it will run
 number-of-cpus jobs in parallel.
-.IP "\fB\-j\fR \-\fIN\fR" 9
+.IP "\fB\-j\fR \fI\-N\fR" 9
 .IX Item "-j -N"
 Subtract N from the number of CPUs.  Run this many jobs in parallel.
 If the evaluated number is less than 1 then 1 will be used.
@@ -205,7 +205,13 @@ output from different commands to be mixed. Can be reversed with \fB\-g\fR.
 Verbose.  Print the job to be run. Can be reversed with \fB\-s\fR.
 .IP "\fB\-x\fR" 9
 .IX Item "-x"
-xargs.  Insert as many arguments as the command line length permits.
+xargs. Insert as many arguments as the command line length permits. If
+{} is not used the arguments will be appended to the line.  If {} is
+used multiple times each {} will be replaced with all the arguments.
+.IP "\fB\-X\fR" 9
+.IX Item "-X"
+xargs with context replace. This works like \fB\-x\fR except if {} is part
+of a word (like \fIpic{}.jpg\fR) then the whole word will be repeated.
 .SH "EXAMPLE 1: Working as cat | sh. Ressource inexpensive jobs and evaluation"
 .IX Header "EXAMPLE 1: Working as cat | sh. Ressource inexpensive jobs and evaluation"
 \&\fBparallel\fR can work similar to \fBcat | sh\fR.

unittest/actual-results/test10

@@ -1,4 +1,10 @@
 33bf8b2986551515cdaff5e860618098  -
 960bedf6398273937e314fb49c7b3ffa  -
-8f7a50abe8d1024e90a2bc9c99ee0b05  -
+b35d8e49be8d94899b719c40d3f1f4bb  -
-      3   80000  468894
+      3   60000  348894
+1foo bar2foo bar3 Afoo barBfoo barC
+1foo2foo3 1bar2bar3 AfooBfooC AbarBbarC
+1c0c49286e5b5b18437e51b438ea5475  -
+      6  119994  697800
+1c0c49286e5b5b18437e51b438ea5475  -
+Chars per line: 116300

unittest/tests-to-run/test10.sh

@@ -5,4 +5,13 @@ seq 1 40 | parallel -j 0 seq 1 10  | sort |md5sum
 seq 1 40 | parallel -j 0 seq 1 10 '| parallel -j 3 echo' | sort |md5sum
 
 # Test of xargs
-seq 1 80000 | parallel -x echo  | mop -d 4 "|sort |md5sum" "| wc" 
+seq 1 60000 | parallel -x echo  | mop -d 4 "|sort |md5sum" "| wc" 
+(echo foo;echo bar) | parallel -x echo 1{}2{}3 A{}B{}C
+(echo foo;echo bar) | parallel -X echo 1{}2{}3 A{}B{}C
+seq 1 60000 | parallel -x echo 1{}2{}3 | mop -d 4 "|sort |md5sum" "| wc" 
+seq 1 60000 | parallel -x echo 1{}2{}3 | \
+  mop -q "|sort |md5sum" :parallel
+echo -n "Chars per line: "
+CHAR=$(cat ~/.mop/:parallel | wc -c)
+LINES=$(cat ~/.mop/:parallel | wc -l)
+echo "$CHAR/$LINES" | bc

unittest/wanted-results/test10

@@ -1,4 +1,10 @@
 33bf8b2986551515cdaff5e860618098  -
 960bedf6398273937e314fb49c7b3ffa  -
-8f7a50abe8d1024e90a2bc9c99ee0b05  -
+b35d8e49be8d94899b719c40d3f1f4bb  -
-      3   80000  468894
+      3   60000  348894
+1foo bar2foo bar3 Afoo barBfoo barC
+1foo2foo3 1bar2bar3 AfooBfooC AbarBbarC
+1c0c49286e5b5b18437e51b438ea5475  -
+      6  119994  697800
+1c0c49286e5b5b18437e51b438ea5475  -
+Chars per line: 116300