use warnings;
use strict;
use Getopt::Long;
use Pod::Usage;
my %options = ( based_on => 'tp',
                top      => 1
               );
GetOptions( \%options,
            'based_on=s',
            'top=i',
            'man',
            'help',
          ) || pod2usage(2);

pod2usage(1) if $options{'help'};
pod2usage( '-verbose' => 2 ) if $options{'man'};

##</code><code>##

%> myprog -based_on sn -top 5
# or as 
%> myprog -top 3 -based_on sn
#or you can use the automaticly provided abbreviation recognition ...
%> myprog -base sn -t 2
# or use tht default values
%> myprog

##</code><code>##

#!/usr/bin/perl 

##</code><code>##

perldoc perltoc