Looking for a “find and replace” program for strings in php

Hi there.
I am looking to translate a theme into my language, and I wanted a way to easly find all the strings the theme has in them (like “categories”, “comments” and so on), so I could easily rtanslate them.

Is there a tool that can easily find for me all of these strings – and allow me to replace them with my own language translation ?

(assuming that theme doesn’t have PO/MO files).

Thanks a bunch !

Tal.