opendir DIR, $dir
  or die "Couldn't open directory '$dir' : $!";
my @files = grep { /(.*)\.mrg$/ and not -f "$dir/$1.did" } readdir DIR;
closedir DIR;

##</code><code>##

  opendir DIR, $dir
    or die "Couldn't read '$dir' : $!";
  my @all_files = map { lc $_ } readdir DIR;
  closedir DIR;
  my %did = map { /(.*)\.did$/ and ($1 => 1) } grep { /\.did$/ } @all_files;
  my @files = grep { /(.*)\.mrg$/ and not $did{$1} } @all_files;

##</code><code>##

  # return a list or a reference to an array, depending
  # on what the caller wants:
  return wantarray ? @files : \@files;

##</code><code>##

perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ;    # The  
$d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider
($c = $d->accept())->get_request(); $c->send_response( new   #in the
HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' #  web