#!/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;
}