#!/usr/bin/perl

use warnings;
use strict;
use File::stat;

my $file = '/bin/su';
my $oldtime = 'Sun Apr 23 08:48:54 2006';

my $sb = stat($file) || die "something went wrong :/";

my $newtime = scalar localtime $sb->mtime;

if($newtime ne $oldtime) {
  print "Warning, file was modified!\n";
} else {
  print "no modification\n";
}