And why might that be? Here are some possibilities:

1. You don't know what recursion is.
2. You do know what recursion is, but have no idea how to do it in perl.
3. You know what it is and how to do it, but cannot see how it applies to your problem.
4. You've decided it would be better not to roll your own but don't know how to look for appropriate existing code.
5. You've found some existing code but don't know how to implement it in your script.

If you want to pick a number that would give us a bit more idea of why you are stuck and hence how you can be assisted.