For the sake of cuteness, this:

  if ($_ < $bytepos) {
    print '< ';
  }
  if ($_ > $bytepos) {
    print '> ';
  }
  if ($_ == $bytepos) {
    print '* ';
  }
[download]

can become:

  print qw(* > <)[$_ <=> $bytepos];
[download]

Whoosh, that was fun :-)

You should also be careful about feeding a negative index into substr, which could happen with a low enough bytepos.

update: deleted a bit of misguided foolishness.

   MeowChow                                   
               s aamecha.s a..a\u$&owag.print