See https://news.ycombinator.com/item?id=5507537 ;)

Want to become efficient at writing short Perl snippets that do one task well? Check out my book "Perl One-Liners Explained":

http://www.catonmat.net/blog/perl-book/

You can read the first chapter here:

http://www.catonmat.net/blog/introduction-to-perl-one-liners...

And http://hop.perl.plover.com/