Using the built-in debugger of Perl as REPL
Source: Perl Maven on the 2011-06-22.
Speaker: Gabor Szabo (szabgab) speaker
The command line debugger that comes with perl is very powerful. Not only does it allow us to debug script but it can be used as a REPL - a Read Eval Print Loop to explore the capabilities of the language. There are a few basic examples in this screencast.
For another related screencast see http://www.youtube.com/watch?v=jiYZcV3khdY
To see all the Perl tutorials visit http://perlmaven.com/perl-tutorial
About Perl Programming and Perl programmers.
In this screencast:
p - print scalar x - print data structure b subname - set breakpoint