the perl debugger "perl -d progname.pl" has an option to dump call stack. Beware though, that some functions may never get called during a particular run, depending on program input. if the code in a program is long, not well documented, and code is not trusted..then you may spend more time looking at code rather than re-writing it. For any program roughly 100 lines or more, it's impossible to keep it all in your head...so when you write/rewrite long code, more than mere comments is needed as documentation. A flow chart is so helpful when reviewing even your own code that you haven't looked at for some time.