parcat: --rm, reading args from stdin.

CREDITS

@@ -1,3 +1,6 @@
+People who have helped GNU Parallel different ways.
+
+John Rusnak: Feedback on all documentation.
 FrithMartin: Bug patch for orphan blocks.
 Rasmus Villemoes: Code snips for signal processing.
 Martin d'Anjou: Code snips for signal processing.

Makefile.am

@@ -119,4 +119,4 @@ monitorman:
 # If man page changed: open new pdfman
 	inotifywait -qmre MOVED_TO -e CLOSE_WRITE --format %w%f . | parallel -uj1 'echo {=/\.pod$$/ or skip()=};make -j && sudo make install; pdfman {/.} &'
 
-EXTRA_DIST = CITATION CREDITS
+EXTRA_DIST = CITATION CREDITS cc-by-sa.txt fdl.txt

Makefile.in

@@ -275,7 +275,7 @@ top_build_prefix = @top_build_prefix@
 top_builddir = @top_builddir@
 top_srcdir = @top_srcdir@
 SUBDIRS = src
-EXTRA_DIST = CITATION CREDITS
+EXTRA_DIST = CITATION CREDITS cc-by-sa.txt fdl.txt
 all: config.h
 	$(MAKE) $(AM_MAKEFLAGS) all-recursive
 

doc/release_new_version

@@ -195,6 +195,8 @@ file:///home/tange/privat/parallel/doc/release_new_version
 
 from:tange@gnu.org
 to:parallel@gnu.org, bug-parallel@gnu.org
+stable-bcc: Jesse Alama <jessealama@fastmail.fm>
+
 
 Subject: GNU Parallel 20170822 ('<<>>') released <<[stable]>>
 
@@ -214,10 +216,24 @@ New in this release:
   http://meta.askubuntu.com/a/16750/22307
   http://meta.serverfault.com/a/9040/45704
 
-* GNU Parallel was cited in:
+* GNU Parallel was cited in: https://springerplus.springeropen.com/articles/10.1186/s40064-016-2022-y
+
+https://dzone.com/articles/running-bash-commands-in-parallel-1
 
 * https://medium.com/@nornagon/today-i-learned-gnu-parallel-plate-tectonics-9fcf24045e63
 
+* https://www.upf.edu/web/sct-sit/gnu-parallel-tutorial
+
+
+http://blogs.fluidinfo.com/terry/2017/08/05/do-stuff-on-things-in-parallel/
+
+http://ino.pm/outreach/presentations/2014/03/genomics-wranglers/index.html#/5
+http://www.ettemalab.org/using-for-loop-vs-gnu-parallel-for-blast/
+
+https://medium.com/@nornagon/today-i-learned-gnu-parallel-plate-tectonics-9fcf24045e63
+
+https://gxnotes.com/article/175866.html
+
 <<Citation not OK: BAMClipper: removing primers from alignments to minimize false-negative mutations in amplicon next-generation sequencing https://www.nature.com/articles/s41598-017-01703-6>>
 
 <<Wrong citation https://iris.sissa.it/retrieve/handle/20.500.11767/36149/10823/And%C3%B2_tesi.pdf>>

src/parcat

@@ -16,24 +16,44 @@ my $okq = Thread::Queue->new();
 my @producers;
 
 if(not @ARGV) {
-    print "Usage:\n";
-    print "  parcat file(s)\n";
+    if(-t *STDIN) {
+	print "Usage:\n";
+	print "  parcat file(s)\n";
+	print "  cat argfile | parcat\n";
+    } else {
+	# Read arguments from stdin
+	chomp(@ARGV = <STDIN>);
+    }
 }
 
+my $files_to_open = 0;
+# Default: fd = stdout
+my $fd = 1;
 for (@ARGV) {
-    push @producers, threads->create('producer', $_);
+    # --rm = remove file when opened
+    /^--rm$/ and do { $opt::rm = 1; next; };
+    # -1 = output to fd 1, -2 = output to fd 2
+    /^-(\d+)$/ and do { $fd = $1; next; };
+    push @producers, threads->create('producer', $_, $fd);
+    $files_to_open++;
 }
 
 sub producer {
     # Open a file/fifo, set non blocking, enqueue fileno of the file handle
     my $file = shift;
+    my $output_fd = shift;
     open(my $fh, "<", $file) || do {
 	print STDERR "parcat: Cannot open $file\n";
 	exit(1);
     };
+    # Remove file when it has been opened
+    if($opt::rm) {
+	unlink $file;
+    }
     set_fh_non_blocking($fh);
-    $q->enqueue(fileno($fh));
     $opened++;
+    # Pass the fileno to parent
+    $q->enqueue(fileno($fh),$output_fd);
     # Get an OK that the $fh is opened and we can release the $fh
     while(1) {
 	my $ok = $okq->dequeue();
@@ -48,31 +68,38 @@ my $s = IO::Select->new();
 my %buffer;
 
 sub add_file {
-    my $fd = shift;
-    open(my $fh, "<&=", $fd) || die;
-    $s->add($fh);
+    my $infd = shift;
+    my $outfd = shift;
+    open(my $infh, "<&=", $infd) || die;
+    open(my $outfh, ">&=", $outfd) || die;
+    $s->add($infh);
     # Tell the producer now opened here and can be released
-    $okq->enqueue($fd);
+    $okq->enqueue($infd);
     # Initialize the buffer
-    @{$buffer{$fh}} = ();
+    @{$buffer{$infh}{$outfd}} = ();
+    $Global::fh{$outfd} = $outfh;
 }
 
 sub add_files {
     # Non-blocking dequeue
-    while(defined(my $fd = $q->dequeue_nb())) {
-	add_file($fd);
-    }
+    my ($infd,$outfd);
+    do {
+	($infd,$outfd) = $q->dequeue_nb(2);
+	if(defined($outfd)) {
+	    add_file($infd,$outfd);
+	}
+    } while(defined($outfd));
 }
 
 sub add_files_block {
     # Blocking dequeue
-    my $fd = $q->dequeue();
-    add_file($fd);
+    my ($infd,$outfd) = $q->dequeue(2);
+    add_file($infd,$outfd);
 }
 
 
 my $fd;
-my (@ready,$file,$rv,$buf);
+my (@ready,$infh,$rv,$buf);
 do {
     # Wait until at least one file is opened
     add_files_block();
@@ -83,43 +110,46 @@ do {
 	    if(not @ready) {
 		add_files();
 	    }
-	    for $file (@ready) {
-		$rv = sysread($file, $buf, 65536);
-		if (!$rv) {
-		    if($! == EAGAIN) {
-			# Would block: Nothing read
-			next;
+	    for $infh (@ready) {
+		# There is only one key, namely the output file descriptor
+		for my $outfd (keys %{$buffer{$infh}}) {
+		    $rv = sysread($infh, $buf, 65536);
+		    if (!$rv) {
+			if($! == EAGAIN) {
+			    # Would block: Nothing read
+			    next;
+			} else {
+			    # Nothing read, but would not block:
+			    # This file is done
+			    $s->remove($infh);
+			    syswrite($Global::fh{$outfd},"@{$buffer{$infh}{$outfd}}");
+			    delete $buffer{$infh};
+			    # Closing the $infh causes it to block
+			    # close $infh;
+			    add_files();
+			    next;
+			}
+		    }
+		    # Something read.
+		    # Find \n or \r for full line
+		    my $i = (rindex($buf,"\n")+1);
+		    if($i) {
+			# Print full line
+			for(@{$buffer{$infh}{$outfd}}, substr($buf,0,$i)) {
+			    syswrite($Global::fh{$outfd},$_);
+			}
+			# @buffer = remaining half line
+			$buffer{$infh}{$outfd} = [substr($buf,$i,$rv-$i)];
 		    } else {
-			# This file is done
-			$s->remove($file);
-			print @{$buffer{$file}};
-			delete $buffer{$file};
-			# Closing the $file causes it to block
-			# close $file;
-			add_files();
-			next;
+			# Something read, but not a full line
+			push @{$buffer{$infh}{$outfd}}, $buf;
 		    }
-		}
-
-		# Find \n for full line
-		my $i = (rindex($buf,"\n")+1);
-		if($i) {
-		    # Print full line
-		    for(@{$buffer{$file}}, substr($buf,0,$i)) {
-			syswrite(STDOUT,$_);
-		    }
-		    # @buffer = remaining half line
-		    @{$buffer{$file}} = (substr($buf,$i,$rv-$i));
-		    redo;
-		} else {
-		    # Something read, but not a full line
-		    push @{$buffer{$file}}, $buf;
 		    redo;
 		}
 	    }
 	}
     }
-} while($opened <= $#ARGV);
+} while($opened < $files_to_open);
 
 
 for (@producers) {
@@ -139,4 +169,3 @@ sub set_fh_non_blocking {
     $flags |= &O_NONBLOCK; # Add non-blocking to the flags
     fcntl($fh, &F_SETFL, $flags) || die $!; # Set the flags on the filehandle
 }
-

src/parcat.pod

@@ -19,15 +19,20 @@ you use:
 
 =head1 EXAMPLES
 
-=head2 Do be done
+=head2 Simple line buffered output
 
-  mkfifo slot-{1..5}-digit-{0..9}
-  parallel -j5 'seq 100000 | grep {} > slot-{%}-digit-{}' ::: {0..9} &
-  parallel parcat slot-{1..5}-digit-{} '>' digit-{} ::: {0..9}
+GNU Parallel saves output to tempfiles. If the amount of data is
+bigger than the free disk space, then you can use this technique to do
+line buffering without saving to disk:
+
+  mkfifo slot-{1..5}
+  seq 10000000 | parallel -j5 --round --pipe 'cat > slot-{%}' &
+  parcat slot-{1..5} | wc
 
 =head1 REPORTING BUGS
 
-GNU B<parcat> is part of GNU B<parallel>. Report bugs to <bug-parallel@gnu.org>.
+GNU B<parcat> is part of GNU B<parallel>. Report bugs to
+<bug-parallel@gnu.org>.
 
 
 =head1 AUTHOR

testsuite/tests-to-run/parallel-local-0.3s.sh

@@ -728,6 +728,25 @@ par_X_eta_div_zero() {
 	perl -pe 's/\d+/0/g'
 }
 
+par_parcat_args_stdin() {
+    echo 'bug #51690: parcat: read args from stdin'
+    tmp1=$(tempfile)
+    tmp2=$(tempfile)
+    echo OK1 > $tmp1
+    echo OK2 > $tmp2
+    (echo $tmp1
+     echo $tmp2) | parcat
+    rm $tmp1 $tmp2
+}
+
+par_parcat_rm() {
+    echo 'bug #51691: parcat --rm remove fifo when opened'
+    tmp1=$(tempfile)
+    echo OK1 > $tmp1
+    parcat --rm $tmp1
+    rm $tmp1 2>/dev/null || echo OK file removed
+}
+
 export -f $(compgen -A function | grep par_)
 compgen -A function | grep par_ | sort |
     parallel -j6 --tag -k --joblog +/tmp/jl-`basename $0` '{} 2>&1'

testsuite/tests-to-run/parallel-local-3s.sh

@@ -152,5 +152,28 @@ newlines"' ::: a b c d e | sort
     ) | perl -pe 's/\0/<null>/g;s/\d+/./g'
 }
 
+par_parcat_mixing() {
+    echo 'parcat output should mix: a b a b'
+    mktmpfifo() {
+	tmp=$(tempfile)
+	rm $tmp
+	mkfifo $tmp
+	echo $tmp
+    }
+    slow_output() {
+	string=$1
+	perl -e 'print "'$string'"x9000,"start\n"'
+	sleep 1
+	perl -e 'print "'$string'"x9000,"end\n"'
+    }
+    tmp1=$(mktmpfifo)
+    tmp2=$(mktmpfifo)
+    slow_output a > $tmp1 &
+    sleep 0.5
+    slow_output b > $tmp2 &
+    parcat $tmp1 $tmp2 | tr -s ab
+}
+
+
 export -f $(compgen -A function | grep par_)
 compgen -A function | grep par_ | sort | parallel -j6 --tag -k '{} 2>&1'

testsuite/wanted-results/parallel-local-3s

@@ -52,6 +52,11 @@ par_multiline_commands	finish 2
 par_multiline_commands	parallel: Warning: Command lines contain newline. Forcing --null.
 par_multiline_commands	3
 par_multiline_commands	finish 3
+par_parcat_mixing	parcat output should mix: a b a b
+par_parcat_mixing	astart
+par_parcat_mixing	bstart
+par_parcat_mixing	bend
+par_parcat_mixing	aend
 par_pipepart_block	### --pipepart --block -# (# < 0)
 par_pipepart_block	1
 par_pipepart_block	2