Regular Expressions

Summary

Having a good grasp of regular expressions is a necessary prerequisite to working with mod_rewrite. All too often, people try to build regular expressions by the brute-force method, trying various different combinations at random until something seems to mostly work. This results in expressions that are inefficient and fragile, as well as being a great waste of time and the cause of much frustration.

Keep a bookmark in this chapter, and refer back to it when you’re trying to figure out what a particular regex is doing.

Other recommended reference sources include the Perl regular expression documentation, which you can find online at http://perldoc.perl.org/perlre.html or by typing perldoc perlre at your command line, and the PCRE documentation, which you can find online at http://pcre.org/pcre.txt.