#!/usr/bin/perl
use strict;
use warnings;

my $input = "      -rw-r--r-- 3  owner   group   size  Feb 25 11:37 filename";

$input =~ s~^\s+~~;
$input =~ s~\s+$~~;

my @felder = split /\s+/, $input;

my %monatsnummer = ( 'Jan' => '01',
                     'Feb' => '02',
                     'Mar' => '03',
                     'Apr' => '04',
                     'Mai' => '05',
                     'Jun' => '06',
                     'Jul' => '07',
                     'Aug' => '08',
                     'Sep' => '09',
                     'Oct' => '10',
                     'Nov' => '11',
                     'Dec' => '12',
                   );
my $ergebnis = $monatsnummer{$felder[5]} .
               sprintf("%02s%05s", $felder[6], $felder[7]);
$ergebnis =~ y/://d;

print "$ergebnis\n";