A handy Perl script to calculate duration in seconds

#!/usr/bin/perl

use strict;
use warnings;
use DateTime;

my $dt2 = DateTime->new(
                       year   => 2013,
                       month  => 8,
                       day    => 2,
                       hour   => 9,
                       minute => $ARGV[0],
                       second => $ARGV[1],
                       time_zone => 'local',
                     );

my $dt1 = DateTime->new(
                       year   => 2013,
                       month  => 8,
                       day    => 2,
                       hour   => 9,
                       minute => $ARGV[2],
                       second => $ARGV[3],
                       time_zone => 'local',
                     );

my $duration = int($dt1->subtract_datetime_absolute($dt2)->delta_seconds);

print "duration: $duration\n";

__END__