Option and Configuration Processing Made Easy
Many useful programs take arguments and configuration options. It's easy to add one or two, but as your program grows, the difficulty of allowing configuration concisely and intelligently also grows. Jon Allen demonstrates how to unify argument and configuration processing in a way that lets you write good code and your users get on with their work.
Link: http://www.perl.com/pub/a/2007/07/12/options-and-configuration.html?CMP=OTC-BD0016219291&ATT=Option+and+Configuration+Processing+Made+Easy