Unpound

Perl input filter for debugging by uncommenting debug statements.

Lets you write things like:

#debug# print "This code is not normally even evaluated\n";

Ordinarily not even evaluated, so there is no performance hit in checking for debugging variables, but then you can run

$ perl -MFilter::Unpound=debug script.pl

and suddenly those lines become active. Multi-line comments, shortcuts for simple prints, etc are supported.