#!/bin/perl-5.8.3/bin/perl$

 use warnings;

 use strict;

 use Data::Dumper;

 use Getopt::Long;

 use Pod::Usage;

 our $g_opts;

 our $optionX=''; #if not defined in command line, it will be empty string

 sub parse_opts{

     my $result = GetOptions(

                     "optionA=s" => \$g_opts->{'optionA'},#string

                     "optionB=s" => \$g_opts->{'optionB'},#string

                     "optionC=i" => \$g_opts->{'optionC'},#integer

                     "optionD=f" => \$g_opts->{'optionD'},#float

                     "optionX=f" => \$optionX,

                     "optionY=f" => \$optionY,

                     "verbose"   => \$g_opts->{'verbose'},#flag

                     "quiet"     => sub { $g_opts->{'verbose'} =  },

                     "help|?"    => \$g_opts->{'help'}

                   );

     if(!($g_opts->{'optionA'})){

         &pod2usage( -verbose => );#exit status will be 1

     }

     if($g_opts->{'help'}){

         &pod2usage( -verbose => );#exit status will be 1

     }

 }

 &parse_opts();

 print("\n$optionX\n");

 print($optionY); #if not defined in command line, it will be undefined

 print($g_opts->{"optionB"});

 foreach my $key (keys %{$g_opts}){

   if(!$g_opts->{$key}) {next;}

   print($key . "=" . $g_opts->{$key} . "\n");

   }

  exit();

  __END__  =head1 NAME

  sample - Using Getopt::Long and Pod::Usage

  =head1 SYNOPSIS

  sample [options] [args ...]

  Options:     -optionA         optionA

    -optionB         optionB

    -optionC         optionC

    -optionD         optionD

    -verbose         verbose

    -quiet           noverbose

    -help            brief help message

  =head1 OPTIONS

  =over   =item B<-help>  Print a brief help message and exits.  =back

  =head1 DESCRIPTION

  B<This program> will read the given input file(s) and do something

 useful with the contents thereof.  =cut