[harmil]

I gave a separate answer for Perl 6, but as for Perl 5: Yes, absolutely. I think everyone should know Perl 5 if you ever touch a Linux system. It's installed everywhere and gives you the largest power/keystroke for command-line utility. It's more effective to learn Perl than AWK and Perl has incredibly deep Unicode support and what I call 4th-generation regular expressions (pre-POSIX, POSIX, and then the explosion of early Perl/PCRE/Python-re being the first three and Perl 6's full parser engine being the 5th) which, together, make it like the mythical tool it's often labeled as: the Swiss Army chainsaw.

Don't make the mistake of trying to write anything over a few lines in it, though. You'll find yourself in a deep hole trying to use Moose and "experimental" features just to get back to parity with every other modern language, and you'll still have thin if any support for many modern tools (i.e. those that entirely post-date 2010).