- included on a line after a configuration directive. Blank lines
- and white space occurring before a directive are ignored, so
- you may indent directives for clarity.</p>
-
- <p>The values of shell environment variables can be used in
- configuration file lines using the syntax <code>${ENVVAR}</code>.
- If "ENVVAR" is the name of a valid environment variable, the value
- of that variable is substituted into that spot in the
- configuration file line, and processing continues as if that text
- were found directly in the configuration file. (If the ENVVAR
- variable is not found, the characters "${ENVVAR}" are left
- unchanged for use by later stages in the config file
- processing.)</p>
-
- <p>The maximum length of a line in the configuration file, after
- environment-variable substitution, joining any continued lines and
- removing leading and trailing white space, is 8192 characters.</p>
+ included on the same line as a configuration directive.
+ White space occurring before a directive is ignored, so
+ you may indent directives for clarity. Blank lines are also ignored.</p>
+
+ <p>The values of variables defined with the <code class="directive"><a href="./mod/core.html#define">Define</a></code> of or shell environment variables can
+ be used in configuration file lines using the syntax <code>${VAR}</code>.
+ If "VAR" is the name of a valid variable, the value of that variable is
+ substituted into that spot in the configuration file line, and processing
+ continues as if that text were found directly in the configuration file.
+ Variables defined with <code class="directive"><a href="./mod/core.html#define">Define</a></code> take
+ precedence over shell environment variables.
+ If the "VAR" variable is not found, the characters <code>${VAR}</code>
+ are left unchanged, and a warning is logged.
+ Variable names may not contain colon ":" characters, to avoid clashes with
+ <code class="directive"><a href="./mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>'s syntax.</p>
+
+ <p>Only shell environment variables defined before the server is started
+ can be used in expansions. Environment variables defined in the
+ configuration file itself, for example with <code class="directive"><a href="./mod/mod_env.html#setenv">SetEnv</a></code>, take effect too late to be used for
+ expansions in the configuration file.</p>
+
+ <p>The maximum length of a line in normal configuration files, after
+ variable substitution and joining any continued lines, is approximately
+ 16 MiB. In <a href="configuring.html#htaccess">.htaccess files</a>, the
+ maximum length is 8190 characters.</p>
projects / apache / blobdiff