#excert from tachyon's code at http://www.perlmonks.org/?node_id=157851
my @dirs  = ($root);

for my $path (@dirs){
    opendir ( DIR, $path ) or next;   # skip dirs we can't read
    while (my $file = readdir DIR) {
      next if $file eq '.' or $file eq '..'; # skip dot files
           if ( -d $path.$file ) {
            push @dirs, $path.$file.'/';     # add dir to list
        } 
    }
    closedir DIR;
}