"walks you through both the built-in Perl debugger and CPAN's Devel::ptkdb. The Perl debugger is powerful but
frustrating to navigate. CPAN's Devel::ptkdb, on the other hand, works wonders by simplifying code debugging and thereby saving
hours of your precious time. In his discussion Zlatanov concentrates on explaining debugging methods and general concepts rather
than looking at specific tools." (thanks
luke)