Tip: PHP also supports regular expressions using a Perl-compatible syntax using the PCRE functions. Those functions support non-greedy matching, assertions, conditional subpatterns, and a number of other features not supported by the POSIX-extended regular expression syntax.
These regular expression functions are not binary-safe. The PCRE functions are.
Regular expressions are used for complex string manipulation in PHP. The functions that support regular expressions are:
These functions all take a regular expression string as their first argument. PHP uses the POSIX extended regular expressions as defined by POSIX 1003.2. For a full description of POSIX regular expressions see the regex man pages included in the regex directory in the PHP distribution. It's in manpage format, so you'll want to do something along the lines of man /usr/local/src/regex/regex.7 in order to read it.
Do not change the TYPE unless you know what you are doing.
To enable regexp support configure PHP --with-regex[=TYPE]. TYPE can be one of system, apache, php. The default is to use php.
The windows version of PHP has built in support for this extension. You do not need to load any additional extension in order to use these functions.
Example 1. Regular Expression Examples