Configuration reference an overview
The configuration file config.php contains a number of settings and variables that heavily influence how Moodle operates. It is located in the main directory of your Moodle system ($CFG->dirroot) and can be edited with any text editor.
Note
Be careful when modifying config.php! Moodle depends heavily on its content and any faults can cause the software to malfunction.
It is recommended that you create a backup of the config.php file before modifying it, so you can roll back to it in case of problems. Also, make sure that the file permissions are set properly as the file contains the database username and password. In a Linux environment, the owner and the group should be set to root, and the permissions should be set to 644.
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The values in the config.php file that we are interested in are the ones that start with a dollar symbol. Each parameter has the following information format:
$<object>-><parameter> = <value>;
<object> is the part of Moodle in which the parameter is used ($CFG or $THEME). Third-party modules or custom distributions might have introduced their own objects; for example, $TOTARA. We will focus on $CFG objects as these are most relevant to administrators.
<parameter> is the name of the configuration setting. Each setting has a unique identifier.
<value> is the type of values the parameter accepts. This depends on the type of the setting. The following table provides the information for each of the key types:
|
Type |
Moodle field |
Values |
|---|---|---|
|
Binary |
Checkbox |
|
|
Numeric |
Number field |
The number itself. |
|
String |
Text field |
Text has to be surrounded by single quotes. |
|
Password |
Password field |
Passwords have to be surrounded by single quotes. |
|
List |
Drop-down menu |
Each value is represented by a number or a string. Unfortunately, there is no consistency for the allocation. For example, while the |
|
Array |
Multi-select menu |
The same applies as for the List type. Values are separated by commas. Again, check the config changes report to be on the safe side. |
Each parameter has to be terminated by a semicolon. To comment out a parameter, precede it with two forward slashes.
Before we deal with the different types of settings, let's have a look at the number of tools that might be useful. As there is no list of available settings, you will have to generate your own. To do so, execute the following shell command in your $CFG->dirroot:
grep -r -h -o '\$CFG->[a-z][[:alnum:]_]*' . | sort-u
This will generate a list of all available $CFG variables in alphabetical order.
If you are experimenting with configuration variables, you might consider installing the Admin setting presets block, which lets users with the site configuration capability to export the site settings to .xml presets, import other sites .xml presets, load (totally or partially) presets settings, and rollback the applied changes if necessary. You can find more information about the tool at: docs.moodle.org/en/Admin_presets_block.
Moodle provides a report that lets you monitor all the changes to any configuration settings via the administration interface. You can find the report at Reports | Config changes:
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Another tool that might be useful when dealing with configuration settings across multiple Moodle sites is called Moodle flavours. A flavour is a set of Moodle site settings, plugins, and language packs (docs.moodle.org/dev/Moodle_flavours).While its key objective is to package, distribute, and deploy the same settings and add-ons to multiple Moodle sites, it can also be used to back up and restore the configuration settings of your Moodle site. You can download the latest version of the plugin from moodle.org/plugins/view.php?plugin=local_flavours. Once installed (see Chapter 14, Installing Third-party Add-ons), you can select the settings to be packaged up in a flavour:
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