#!/usr/local/bin/perl

use warnings;
use strict;

use Date::Format;
use Date::Parse;

my $str = "Thu, 7 Aug 2008 08:35:36 +01:00";
my $time = str2time($str);
print qq{time: $time\n};

my $datekey = time2str(q{%Y%m%d}, $time);
print qq{datekey: $datekey\n};

__DATA__
ouputs:

time: 1218094536
datekey: 20080807