I'm needed to do further processing on the contents of a tar file. Manually, I'm simply issue: 

$ tar txf syssrc.tgz > /tmp/file

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...to create a list of directories & files, but doing this programmatically within a Perl script is giving me problems.

If I don't redirect, the following code works: 

#!/usr/bin/perl

use strict;
use warnings;
use Readonly;

Readonly my $filename => '/tmp/contents';

my $args = 'tf';

eval {
    die 'incorrect #command-line arguments' unless @ARGV == 1;
                                                              
    #   add switches based on filetype                        
    if ($ARGV[0] =~ /tgz$/) {         
        $args .= 'z';
    }
                    
    #   dump tar contents to file
    if (system('tar', $args, $ARGV[0]) != 0) {
        if ($? == -1) {
            die "failed to execute '$!'";
        }
        elsif ($? & 127) {
            die sprintf 'child process died with signal %d %s',
                ($? & 127), (($? & 128) ? 'with coredump' : '');
        }
        else {
            printf "child process exit value:\t%d\n", ($? >> 8);
        }
    }    
};
if ($@) {
    $@ =~ s/at $0 line \d+\.$//;
    print "syntax:\t$0 <filename>\n";
    print "error:\t$@\n";            
}

..but if I change the <b>system()</b> call to:

<code>
if (system('tar', $args, $ARGV[0], '>', $filename) != 0) {

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I get the following warning: 
tar: WARNING! These patterns were not matched:
>
/tmp/contents
child process exit value:       1

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...and /tmp/file is not created.

In reply to tar, system() & pipes? by Anonymous Monk

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