Regular expressions
===================

A regular expression (regex or regexp for short) is a special text string for describing a search pattern. You can think of regular expressions as wildcards on steroids. You are probably familiar with wildcard notations such as ``*.txt`` to find all text files in a file manager. The regex equivalent is ``.*\.txt$``. [1]_

To understand and learn more about regular expressions and implementations of these, recommended read.

* `Regular Expression Quick Start <http://www.regular-expressions.info/quickstart.html>`_
* `Regular Expression Tutorial <http://www.regular-expressions.info/tutorial.html>`_
* `Jeffrey E.F. Friedl, January 1997, Mastering Regular Expressions. O'Reilly Media, pp 368. <http://shop.oreilly.com/product/9781565922570.do>`_

.. rubric:: Footnotes

.. [1] `Regular-Expressions.info <http://www.regular-expressions.info>`_