If you’ll be spending a significant amount of time around Unix or Linux as a sysadmin or developer, it’s definitely worth learning. Like vi, it will always be there. Larry Wall characterized Perl as inhabiting the void between the manipulexity of C and the whipuptitude of the shell. When your shell script starts to run out of gas, switch to Perl. For quick text filters or one liners dealing with code or other collections of files, Perl’s keystroke-to-horsepower ratio is challenging to match. Some you use frequently enough that they’re worth tossing into your ~/bin to run from the command line or as a filter inside vi.
It’s refreshing to see an even-handed discussion in the replies here rather than the usual hurr hurr punctuation language bigotry. Perl is a big language. Perl is a quirky language. Perl is a fun language. Perl is an extraordinarily well documented language.
Perl is a different language. The urge among programmers to conform is surprisingly strong. Even computer geeks seem to want to get their kicks bullying the weird kid. In comparison, Python and Java code look so bland, so boring. But the market has clearly decided, and Perl has paid the price for daring to be unorthodox.
The superficial demands of orthodoxy make it an inexpensive substitute for virtue. And that in turn is one of the reasons orthodoxy is so attractive to bad people. You could be a horrible person, and yet as long as you're orthodox, you're better than everyone who isn’t.