Regular Expression Pocket Reference, 2nd Edition

RewriteRule

The rewrite engine enables regular-expression-based rewriting of URLs. The feature is enabled with the RewriteEngine On directive. Most rewrites are a single RewriteRule, or a combination of RewriteCond directives followed by a RewriteRule.

RewriteRule pattern substitution [[FLAG1, FLAG2, ...]]

Rewrites URL to substitution if the URL is successfully matched by pattern. The substitution string can contain back-references ($N) to the RewriteRule pattern, back-references (%N) to the last matched RewriteCond pattern, server-variables as in rule condition test-strings (%{VARNAME} ), and mapping-function calls ( ${mapname:key|default} ). Optional flags, listed in Table 53, cause the server to take various actions when a match occurs.

RewriteCond teststring pattern

Define a test condition (Table 54) for applying a RewriteRule. Multiple RewriteCond directives preceding a RewriteRule are combined with an implicit AND, unless specified as OR. The teststring can contain back-references ($N) to the RewriteRule pattern, back-references (%N) to the last matched RewriteCond pattern, server-variables as in rule condition test-strings ( %{VARNAME}), and mapping-function calls ( ${mapname:key|default}).

Server variables affecting rewrites are listed in Table 55.

Table 1-53. Apache RewriteRule flags

Modes	Meaning
C	Chain with next rule. If rule matches, apply the rewrite, and the following chained rewrites; otherwise, stop the chain.
CO=NAME:VAL:domain[:lifetime[:path]]	Set a cookie.
E=VAR:VAL	Set ...