#!/usr/bin/perl

use strict;
use warnings;

my $datum = '05.12.14 12:00:04';

my $timestamp = $datum;

$timestamp =~ s/(\d{2})\.(\d{2})\.(\d{2})\ (\d{2})\:(\d{2})\:(\d{2})/20$3$2$1$4$5$6/;

print $timestamp;