Select Code to Download

use strict;
use File::Find;
...
open(DB, ">$dbpath/$cod.txt") || die $!;

print DB map { s/\.mp3\z/\n/; $_ } sort @files;

use strict;
use File::Find;
...
sub trim {
   return map { s/\.mp3\z/\n/; $_ } sort @_;
}