I am working on a old code base, where programmers assumed that register_globals will always be on. Hence variables are used without $_GET or $_POST prefix, pretty much in every page (the code base is huge, hundreds of scripts). I tried turning it off, but the very first script (login script) goes on an infinite loop.

I understand that going through one script at a time, and one line at a time and fixing the variables is probably the only option (adding the prefix $_GET or $_POST as the case may be). Has anyone does this before? How did you go about doing it? Any advice?