Apache: The Definitive Guide, 3rd Edition

Rewrite

The preceding section described the Alias module and its allies. Everything these directives can do, and more, can be done instead by mod_rewrite.c, an extremely compendious module that is almost a complete software product in its own right. But for simple tasks Alias and friends are much easier to use.

The documentation is thorough, and the reader is referred to http://www.engelschall.com/pw/apache/rewriteguide/ for any serious work. You should also look at http://www.apache.org/docs/mod/mod_rewrite.html. This section is intended for orientation only.

Rewrite takes a rewriting pattern and applies it to the URL. If it matches, a rewriting substitution is applied to the URL. The patterns are regular expressions familiar to us all in their simplest form — for example, mod.*\.c , which matches any module filename. The complete science of regular expressions is somewhat extensive, and the reader is referred to ... /src/regex/regex.7, a manpage that can be read with nroff -man regex.7 (on FreeBSD, at least). Regular expressions are also described in the POSIX specification and in Jeffrey Friedl’s Mastering Regular Expressions (O’Reilly, 2002).

It might well be worth using Perl to practice with regular expressions before using them in earnest. To make complicated expressions work, it is almost essential to build them up from simple ones, testing each change as you go. Even the most expert find that convoluted regular expressions often do not work the first time.

The essence ...