Do you have the "Function Nodelet" available (its on the right side of my screen)? If so, it shows you a link to all the Perl built in functions which are in your code. The docs are only a click away! If not, you can enable it with Nodelet Settings from your home node.

Docs are also available at your prompt:

perldoc -f chomp
[download]

Tip #2 from the Basic debugging checklist: add print's to your code and run it to see values of variables.