#!/usr/bin/env perl
use warnings;
use strict;
use Getopt::Long;

GetOptions(
  'first' => \&first,
  'second'   => \&second,
  'help'     => \&help,
) or die "Invalid options passed to $0\n";

sub first () {
  print "Processing sub first\n";
}

sub second () {
  print "Processing sub second\n";
}

sub help () {
	print "Available options are: \n";
	print "\t--first\n";
	print "\t--second\n";
	print "\t--third\n";
	print "\t--fourth\n";
	print "\t--help\n";
}

##</code><code>##

***** Output *******
C:\temp>getopts.pl --year --first
Unknown option: year
Processing sub first
Invalid options passed to C:\temp\getopts.pl