for my $val ( qw(1 5 10 24) ) {

    print "Add $val hour ...\n";

    for my $date (qw(1096600000 1099170000) ) {
        print "\tBefore: $date - ".localtime($date)."\n";

        print "\tAfter: ".($date+$val*3600)." - ".localtime($date+$val*3600)."\n";

    }

    print "\n";

}