57.2.1 Customization Groups

For customization purposes, settings are organized into groups to help you find them. Groups are collected into bigger groups, all the way up to a master group called Emacs.

M-x customize creates a customization buffer that shows the top-level Emacs group and the second-level groups immediately under it. It looks like this, in part:

     /- Emacs group: ---------------------------------------------------\
           [State]: visible group members are all at standard settings.
        Customization of the One True Editor.
        See also [Manual].
     
     Editing group: [Go to Group]
     Basic text editing facilities.
     
     External group: [Go to Group]
     Interfacing to external utilities.
     
     more second-level groups
     
     \- Emacs group end ------------------------------------------------/
     

This says that the buffer displays the contents of the Emacs group. The other groups are listed because they are its contents. But they are listed differently, without indentation and dashes, because their contents are not included. Each group has a single-line documentation string; the Emacs group also has a ‘[State]’ line.

Most of the text in the customization buffer is read-only, but it typically includes some editable fields that you can edit. There are also buttons, which do something when you invoke them. To invoke a button, either click on it with Mouse-1, or move point to it and type <RET>.

For example, the phrase ‘[Go to Group]’ that appears in a second-level group is a button. Invoking it creates a new customization buffer, which shows that group and its contents. This is a kind of hypertext link to another group.

The Emacs group includes a few settings, but mainly it contains other groups, which contain more groups, which contain the settings. By browsing the hierarchy of groups, you will eventually find the feature you are interested in customizing. Then you can use the customization buffer to set that feature's settings. You can also go straight to a particular group by name, using the command M-x customize-group.