#!/usr/bin/perl

use strict;
use warnings;
use DateTime;

use constant SECONDS_PER_DAY => 24 * 60 * 60;

my $filename = "20080112BlaFasel.xys";
my ($year,$month,$day) = $filename =~ /(\d{4})(\d\d)(\d\d)/;

my $diff = DateTime->new( year => $year, month => $month, day => $day )
                   ->subtract_datetime_absolute( DateTime->now );

print $diff->seconds / SECONDS_PER_DAY;