Brian D Foy, Perl 

Take the next step toward Perl mastery with advanced concepts that make coding easier, maintenance simpler, and execution faster. Mastering Perl isn't a collection of clever tricks, but a way of thinking about Perl programming for solving debugging, configuration, and many other real-world problems you’ll encounter as a working programmer.

The third in O’Reilly’s series of landmark Perl tutorials (after Learning Perl and Intermediate Perl), this fully upated edition pulls everything together and helps you bend Perl to your will.

Explore advanced regular expressions features
Avoid common problems when writing secure programs
Profile and benchmark Perl programs to see where they need work
Wrangle Perl code to make it more presentable and readable
Understand how Perl keeps track of package variables
Define subroutines on the fly
Jury-rig modules to fix code without editing the original source
Use bit operations and bit vectors to store large data efficiently
Learn how to detect errors that Perl doesn’t report
Dive into logging, data persistence, and the magic of tied variables