Info Catalog elisp: Init File elisp: Starting Up elisp: Command-Line Arguments

elisp: Terminal-Specific

 
 38.1.3 Terminal-Specific Initialization
 ---------------------------------------
 
 Each terminal type can have its own Lisp library that Emacs loads when
 run on that type of terminal.  The library’s name is constructed by
 concatenating the value of the variable ‘term-file-prefix’ and the
 terminal type (specified by the environment variable ‘TERM’).  Normally,
 ‘term-file-prefix’ has the value ‘"term/"’; changing this is not
 recommended.  If there is an entry matching ‘TERM’ in the
 ‘term-file-aliases’ association list, Emacs uses the associated value in
 place of ‘TERM’.  Emacs finds the file in the normal manner, by
 searching the ‘load-path’ directories, and trying the ‘.elc’ and ‘.el’
 suffixes.
 
    The usual role 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 ‘input-decode-map’ if the Termcap or Terminfo entry does
 not specify all the terminal’s function keys.  Terminal Input.
 
    When the name of the terminal type contains a hyphen or underscore,
 and no library is found whose name is identical to the terminal’s name,
 Emacs strips from the terminal’s name the last hyphen or underscore and
 everything that follows it, and tries again.  This process is repeated
 until Emacs finds a matching library, or until there are no more hyphens
 or underscores in the name (i.e., there is no terminal-specific
 library).  For example, if the terminal name is ‘xterm-256color’ and
 there is no ‘term/xterm-256color.el’ library, Emacs tries to load
 ‘term/xterm.el’.  If necessary, the terminal library can evaluate
 ‘(getenv "TERM")’ to find the full name of the terminal type.
 
    Your init file can prevent the loading of the terminal-specific
 library by setting the variable ‘term-file-prefix’ to ‘nil’.
 
    You can also arrange to override some of the actions of the
 terminal-specific library by using ‘tty-setup-hook’.  This is a normal
 hook that Emacs runs after initializing a new text terminal.  You could
 use this hook to define initializations for terminals that do not have
 their own libraries.  Hooks.
 
  -- User Option: term-file-prefix
      If the value of this 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 init
      file if you do not wish to load the terminal-initialization file.
 
      On MS-DOS, Emacs sets the ‘TERM’ environment variable to
      ‘internal’.
 
  -- User Option: term-file-aliases
      This variable is an an association list mapping terminal types to
      their aliases.  For example, an element of the form ‘("vt102" .
      "vt100")’ means to treat a terminal of type ‘vt102’ like one of
      type ‘vt100’.
 
  -- Variable: tty-setup-hook
      This variable is a normal hook that Emacs runs after initializing a
      new text terminal.  (This applies when Emacs starts up in
      non-windowed mode, and when making a tty ‘emacsclient’ connection.)
      The hook runs after loading your init file (if applicable) and the
      terminal-specific Lisp file, so you can use it to adjust the
      definitions made by that file.
 
      For a related feature, window-setup-hook Init File.
 

Info Catalog elisp: Init File elisp: Starting Up elisp: Command-Line Arguments