field: Converted to wrapper for (m)awk.

Makefile

@@ -1,18 +1,19 @@
 CMD = blink 2grep 2search burncpu duplicate-packets em encdir field	\
 	forever fxkill G gitnext gitundo goodpasswd histogram mtrr	\
-	mirrorpdf neno off parsort pdfman pidcmd plotpipe puniq		\
-	ramusage rand rclean rina rn rrm seekmaniac shython		\
+	mirrorpdf neno off parsort pdfman pidcmd pidtree plotpipe	\
+	puniq ramusage rand rclean rina rn rrm seekmaniac shython	\
 	sound-reload splitvideo stdout swapout T timestamp tracefile	\
 	transpose upsidedown vid w4it-for-port-open whitehash		\
 	wifi-reload wssh ytv yyyymmdd
 
 all: blink/blink.1 2search/2grep.1 2search/2search.1			\
-	burncpu/burncpu.1 encdir/encdir.1 G/G.1 gitnext/gitnext.1	\
-	gitundo/gitundo.1 goodpasswd/goodpasswd.1			\
+	burncpu/burncpu.1 encdir/encdir.1 field/field.1 G/G.1		\
+	gitnext/gitnext.1 gitundo/gitundo.1 goodpasswd/goodpasswd.1	\
 	histogram/histogram.1 mirrorpdf/mirrorpdf.1 neno/neno.1		\
 	off/off.1 parsort/parsort.1 pdfman/pdfman.1 pidcmd/pidcmd.1	\
-	plotpipe/plotpipe.1 puniq/puniq.1 rand/rand.1 rina/rina.1	\
-	rn/rn.1 rrm/rrm.1 seekmaniac/seekmaniac.1 shython/shython.1	\
+	pidtree/pidtree.1 plotpipe/plotpipe.1 puniq/puniq.1		\
+	rand/rand.1 rina/rina.1 rn/rn.1 rrm/rrm.1			\
+	seekmaniac/seekmaniac.1 shython/shython.1			\
 	sound-reload/sound-reload.1 splitvideo/splitvideo.1		\
 	stdout/stdout.1 timestamp/timestamp.1 tracefile/tracefile.1	\
 	transpose/transpose.1 T/T.1 upsidedown/upsidedown.1 vid/vid.1	\

field/field

@@ -1,36 +1,133 @@
-#!/usr/bin/perl -an
+#!/usr/bin/perl
 
-# field 1
-# field 3,1
-# field 6,2-3
-# field 6-
-# field 2,6-,2-3
+=pod
 
-BEGIN {
-    @ranges = split(/,/, shift);
+=head1 NAME
+
+field - select fields in tabular files
+
+
+=head1 SYNOPSIS
+
+B<field> I<field spec> file
+
+... | B<field> I<field spec>
+
+
+=head1 DESCRIPTION
+
+B<field> selects fields in tabular files.
+
+
+=head1 EXAMPLE
+
+Select field 2:
+
+  field 2 file
+
+Select field 2,3,4,5:
+
+  field 2-5 file
+
+Select field 2..end:
+
+  field 2- file
+
+Select field 2,3,4,1:
+
+  field 2-4,1 file
+
+
+=head1 AUTHOR
+
+Copyright (C) 2017-2020 Ole Tange,
+http://ole.tange.dk and Free Software Foundation, Inc.
+
+
+=head1 LICENSE
+
+Copyright (C) 2012 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/>.
+
+
+=head1 SEE ALSO
+
+B<cut>
+
+
+=cut
+
+use strict;
+
+my @fields = range_to_fields(shift);
+my $fields = join(",", @fields);
+
+sub range_to_fields {
+    my @ranges = split(/,/, shift);
+    my @fields;
     for (@ranges) {
 	/^(\d+)$/ and push (@fields,($1-1));
 	/^(\d+)-(\d+)$/ and push (@fields,($1-1) .. ($2-1));
 	/^(\d+)-$/ and do {
 	    push (@fields,($1-1)." .. \$#F");
-	    $must_eval = 1;
+	    $Global::must_eval = 1;
 	};
     }
     # Default: field 1
-    if(not @fields) { @fields=(1-1); }
     # Perl counts from 0 - not from 1
-    $fields = join(",", @fields);
-}
-if($must_eval) {
-    if(not $Calc::f{$#F}) {
-	# Eval is expensive, so only do it if we have not done before
-	# If an argument ends in '-' then we must figure out the last field
-	# which depends on the number of fields in the line
-	$Calc::f{$#F}++;
-	@{$Calc::fields->{$#F}} = eval $fields;
-    }
-    print join(" ",@F[@{$Calc::fields->{$#F}}]),"\n";
-} else {
-    print join(" ",@F[@fields]),"\n";
+    if(not @fields) { @fields=(1-1); }
+    return @fields;
 }
 
+if($Global::must_eval) {
+    while(<>) {
+	my @F = split/\s+/,$_;
+	if(not $Calc::f{$#F}) {
+	    # Eval is expensive, so only do it if we have not done before
+	    # If an argument ends in '-' then we must figure out the last field
+	    # which depends on the number of fields in the line
+	    $Calc::f{$#F}++;
+	    @{$Calc::fields->{$#F}} = eval $fields;
+	}
+	print join(" ",@F[@{$Calc::fields->{$#F}}]),"\n";
+    }
+} else {
+    # awk counts from 1 not 0
+    @fields = map { $_+1 } @fields;
+    # Use mawk (60 MB/s)/gawk (30 MB/s)/awk (? MB/s)
+    my $awk = which("mawk") || which("gawk") || which("awk");
+
+    my $awkscript = '{print '.
+			  (join ",", map { '$'.$_ } @fields).
+			  '}';
+    exec($awk,$awkscript);
+}
+
+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(":",$ENV{'PATH'}));
+	if($prg =~ m:/:) {
+	    # Including path
+	    push(@which, grep { not -d $_ and -x $_ } $prg);
+	}
+    }
+    return wantarray ? @which : $which[0];
+}