I guess you want something like this:

#!/usr/bin/env perl

use strict;
use warnings;
use Getopt::Long;
use Pod::Usage;
use Data::Dump;

my %options;

# Getopt::Long::Configure("no_ignore_case"); # perhaps you need it...

GetOptions( \%options, "device=i" );

pod2usage( -exitstatus => 0, -verbose => 2 ) unless defined $options{d
+evice};

dd \%options;

# stuff...

__END__

=pod

=head1 USAGE

Something went wrong.

=cut
[download]

Please see also Re: throw a warning if no argument were passed, Re: GetOpt Organization and Getopt::Long

Regards, Karl