Maybe this example will help: 

#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long;

$| = 1;

my $blah = 0;

if ( scalar( grep( /^-/, @ARGV ) ) ) {
    GetOptions(
        'blah' => sub { $blah = ( $blah ? 0 : 1 ); },
        'help' => \&help
    );
}

printf <<RESULTS, $blah;
Blah: %d
RESULTS

sub help {
    print <<HELPTEXT;

$0 [-blah] [-help]

    -blah   - do something
    -help   - display this help text

HELPTEXT
    exit;
}

[download]

In this contrived example, using the -help option will execute the &help routine, while the -blah option will execute the anonymous subroutine (which in this contrived example flips the value of $blah between true and false).

Hope that helps.

In reply to Re: Getopt::Long subroutine usage by atcroft
in thread Getopt::Long subroutine usage by rockneybot

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