Rebuild HTML - adds the !VAR syntax for the [E] flag.

Environment Variables document</a> for more details on how Environment

variables work.</p>

<p>The following example sets an evironment variable called 'image' to a

<p>The full syntax for this flag is:</p>

<div class="example"><p><code>

[E=VAR:VAL]

[E=!VAR]

</code></p></div>

<p><code>VAL</code> may contain backreferences (<code>$N</code> or

<code>%N</code>) which will be expanded.</p>

<p>Using the short form</p>

<div class="example"><p><code>

[E=VAR]

</code></p></div>

<p>you can set the environment variable named <code>VAR</code> to an

empty value.</p>

<p>The form</p>

<div class="example"><p><code>

[E=!VAR]

</code></p></div>

<p>allows to unset a previously set environment variable named

<code>VAR</code>.</p>

<p>Environment variables can then be used in a variety of

contexts, including CGI programs, other RewriteRule directives, or

CustomLog directives.</p>

<p>The following example sets an environment variable called 'image' to a

value of '1' if the requested URI is an image file. Then, that

environment variable is used to exclude those requests from the access

log.</p>