How to use GetOptions utility to handle 'optional' command-line arguments in Perl?

Question

There are many Perl tutorials explaining how to use GetOptions utility to process only the command-line arguments which are expected, else exit with an appropriate message.

In my requirement I have following optional command-line arguments, like,

• -z zip_dir_path : zip the output
• -h : show help.

I tried few combinations with GetOptions which did not work for me.
So my question is: How to use GetOptions to handle this requirement?

EDIT: -z needs 'zip directory path'

EDIT2: My script has following compulsory command-line arguments:

• -in input_dir_path : Input directory
• -out output_dir_path : Output directory

Here's my code:

my %args;
GetOptions(\%args,
"in=s",
"out=s"
) or die &usage();

die "Missing -in!" unless $args{in};
die "Missing -out!" unless $args{out};

Hope this EDIT adds more clarity.

Answer 1

A : (colon) can be used to indicate optional options:

#!/usr/bin/env perl

use strict;
use warnings;

use Getopt::Long;

my ( $zip, $help, $input_dir, $output_dir );

GetOptions(
    'z:s'   => \$zip,
    'h'     => \$help,
    'in=s'  => \$input_dir,
    'out=s' => \$output_dir,
);