Probably the best resource is Programming Perl (3rd Edition) by Larry Wall, Tom Christiansen, Jon Orwant (Paperback - 1067 pages 3rd edition, July 2000 O'Reilly & Associates; ISBN: 0596000278). Every Perl programmer should have this book.

However, you can find many good online resources. Here are a few, but the first is the most closely related to your question and include some examples:

Perl Command-Line Options (specifically Using the -n and -p options)

A more complete reference can be found at:

Excerpts from Perl 5 by example by David Medinets

You might also want to download and install Copernic 2001, by Copernic Technologies (available for Windows box). It has found many resources for me that I couldn't find via places like perldoc.com, perl.org, or CPAN.

Hope these help are of help.