a2query

List enabled Apache modules

$ sudo a2query -m

$ sudo a2query -m [module_name]

$ sudo a2query -s

$ sudo a2query -M

$ sudo a2query -v

a2query [-q] <type> [<name>]
where <type> is module, site, vhost, conf, or env

-q
    Query mode: print status ('enabled', 'disabled', or absent) for <name> instead of listing all

module
    Operate on modules (lists enabled if no name, queries status with -q)

site
    Operate on sites (lists enabled sites if no name)

vhost
    Operate on virtual hosts (similar to sites)

conf
    Operate on configuration snippets in conf-enabled

env
    Operate on environment variables in envvars.d

<name>
    Specific item to query or filter list (basename without .load/.conf)

The a2query command is a utility script in Debian-based distributions for querying the status of Apache2 configuration components, such as modules, sites, virtual hosts, configuration files, and environment variables. It interacts with the symlinked directory structure under /etc/apache2/, like mods-enabled/, sites-enabled/, etc.

Without arguments, specifying a type (e.g., module) lists all enabled items of that type. Providing a name queries or lists specifics. In query mode (-q), it outputs the status: 'enabled', 'disabled', or indicates absence. Exit codes reflect status: 0 for enabled, 1 for disabled, 2 for not found.

This tool is essential for scripting Apache management, checking prerequisites before enabling features, or verifying configurations. It assumes the standard Debian Apache2 layout and reads symlinks directly, making it lightweight and non-root friendly if paths are readable.

Requires Debian-style Apache2 config (/etc/apache2/*-enabled). Does not reload Apache or modify configs. Non-root access needs read perms on config dirs.

a2query module rewrite → lists or checks rewrite module
a2query -q module rewrite → 'enabled' (exit 0)
a2query -q site 000-default → status of default site

0: enabled
1: disabled
2: not found
3+: error

Developed by Debian Apache packagers around 2004-2005 with the introduction of mods/sites-available/enabled symlink system for easier management. Evolved with Apache2.4 support.

a2enmod(8), a2dismod(8), a2ensite(8), a2dissite(8), apache2(8)