What's the difference between "perl" and "Perl"?

One bit. Oh, you weren't talking ASCII? :-) Larry now uses ``Perl'' to signify the language proper and ``perl'' the implementation of it, i.e. the current interpreter. Hence Tom's quip that ``Nothing but perl can parse Perl.'' You may or may not choose to follow this usage. For example, parallelism means ``awk and perl'' and ``Python and Perl'' look ok, while ``awk and Perl'' and ``Python and perl'' do not.