Info
Regular-Expressions.info – Regex Tutorial, Examples and Reference – Regexp Patterns
Regular Expression Library the Internet’s first Regular Expression Library
BOOST Regex : …one of the most highly regarded and expertly designed C++ library projects in the world.
— Herb Sutter and Andrei Alexandrescu, C++ Coding Standards
Regex for Windows (!! at last GNU they managed to port it !! :P)
Tutorials
The 30 Minute Regex Tutorial By Jim Hollenhorst | 21 Nov 2005 @ Codeproject
PYTHON – Regular Expression HOWTO
PHP Manual Page – Regular Expressions
IBM : Know your regular expressions
Cheat-sheets
Regular Expressions Cheat Sheet (V2)
Online tools
Cool snippets
A regular expression to check for prime numbers : /^1?$|^(11+?)1+$/ in Perl to check if a number is prime or not
Books
Oreilly – Mastering Regular Expressions
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