use strict;

open(PLAYLIST, "<playlist.m3u");
opendir(FILES, 'd:\my files');
my %playlist ;
my @filelist = grep {/\.mp3$/} readdir FILES;
my $song;

while(<PLAYLIST>) {
    chomp;
    if(not(/#/)) {$playlist{$_} = 1}
    }

foreach $song(@filelist) {
    if(!exists $playlist{$song}) {
        unlink($song)
        }
    }

closedir FILES;
close PLAYLIST;