GNU Emacs Lisp Reference Manual

34.1.3: Terminal-Specific Initialization

Each terminal type can have its own Lisp library that Emacs loads when run on that type of terminal. For a terminal type named termtype, the library is called `term/termtype'. Emacs finds the file by searching the load-path directories as it does for other files, and trying the `.elc' and `.el' suffixes. Normally, terminal-specific Lisp library is located in `emacs/lisp/term', a subdirectory of the `emacs/lisp' directory in which most Emacs Lisp libraries are kept.

The library's name is constructed by concatenating the value of the variable term-file-prefix and the terminal type. Normally, term-file-prefix has the value "term/"; changing this is not recommended.

The usual function of a terminal-specific library is to enable special keys to send sequences that Emacs can recognize. It may also need to set or add to function-key-map if the Termcap entry does not specify all the terminal's function keys. See Terminal Input.

When the name of the terminal type contains a hyphen, only the part of the name before the first hyphen is significant in choosing the library name. Thus, terminal types `aaa-48' and `aaa-30-rv' both use the `term/aaa' library. If necessary, the library can evaluate (getenv "TERM") to find the full name of the terminal type.

Your `.emacs' file can prevent the loading of the terminal-specific library by setting the variable term-file-prefix to nil. This feature is useful when experimenting with your own peculiar customizations.

You can also arrange to override some of the actions of the terminal-specific library by setting the variable term-setup-hook. This is a normal hook which Emacs runs using run-hooks at the end of Emacs initialization, after loading both your `.emacs' file and any terminal-specific libraries. You can use this variable to define initializations for terminals that do not have their own libraries. See Hooks.

Variable: term-file-prefix

If the term-file-prefix variable is non-nil, Emacs loads a terminal-specific initialization file as follows:

(load (concat term-file-prefix (getenv "TERM")))

You may set the term-file-prefix variable to nil in your `.emacs' file if you do not wish to load the terminal-initialization file. To do this, put the following in your `.emacs' file: (setq term-file-prefix nil).

Variable: term-setup-hook

This variable is a normal hook that Emacs runs after loading your `.emacs' file, the default initialization file (if any) and the terminal-specific Lisp file.

You can use term-setup-hook to override the definitions made by a terminal-specific file.

See window-setup-hook in Window Systems, for a related feature.