PHP Code Sniffer (PHPCS) is a package for syntax checking, available from PEAR. It can check code against defined rules covering anything from whitespace through doc comments to variable naming conventions and beyond. In this article we'll look at getting started with PHPCS, using it to syntax check our files, and go further to look at how the rules are create and the standards defined.
She goes through the installation (a simple call with the pear installer) and a few examples of code and the matching output for a few of the syntax formats included with the tool. She also has a section on the structure of some of the rules and looks at the sniff for defining functions for the PEAR standard.