Regular Expression Basics
by Volker Weber
Regular expressions, sometimes referred to as regex, grep, or pattern matching, can be a very powerful tool and a tremendous time-saver with a broad range of application. As an extended form of find-and-replace, you can use a regular expression to do things such as perform client-side validation of email addresses and phone numbers, search multiple documents for strings and patterns you wish to change or remove, or extract a list of links from source code. Regex is supported by most languages and tools, but because there can be varying implementations, this article will cover basic principles that are commonly used. (via Schockwellenreiter)
Oops. This "greediness" has killed me more than once.
