Google Message Security for Google Apps Administration Guide - Manual (Page 218)

218 Message Security for Google Apps Administration Guide
About Using Regular Expressions
Content Manager includes a powerful string-matching tool called regular
expressions, often abbreviated as regex. With regular expressions, you can
create filters that can match patterns of text rather than only single words or
phrases.
Regular expressions are a standard tool in many systems and scripting
languages. Regular expressions can be simple or highly complex. This document
provides information about how to use regular expressions with Content Manager,
and can help you create simple expressions. You can find more detailed
information—including tutorials and examples—on many web sites, such as the
following:
• www.regular-expressions.info
• www.regexlib.com