Command Line Switches and Arguments
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XEmacs supports command line arguments you can use to request various actions when invoking Emacs.  The commands are for compatibility with other editors and for sophisticated activities.  If you are using XEmacs under the X window system, you can also use a number of standard Xt command line arguments. Command line arguments are not usually needed for editing with Emacs; new users can skip this section.

Many editors are designed to be started afresh each time you want to edit.  You start the editor to edit one file; then exit the editor.  The next time you want to edit either another file or the same one, you start the editor again.  Under these circumstances, it makes sense to use a command line argument to say which file to edit.

The recommended way to use XEmacs is to start it only once, just after you log in, and do all your editing in the same Emacs process. Each time you want to edit a file, you visit it using the existing Emacs.  Emacs creates a new buffer for each file, and (unless you kill some of the buffers) Emacs eventually has many files in it ready for editing.  Usually you do not kill the Emacs process until you are about to log out.  Since you usually read files by typing commands to Emacs, command line arguments for specifying a file when Emacs is started are seldom needed.

Emacs accepts command-line arguments that specify files to visit, functions to call, and other activities and operating modes.  If you are running XEmacs under the X window system, a number of standard Xt command line arguments are available as well.

The following subsections list:

  * Command line arguments that you can always use

  * Command line arguments that have to appear at the beginning of the argument list

  * Command line arguments that are only relevant if you are running XEmacs under X

Command Line Arguments for Any Position
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Command line arguments are processed in the order they appear on the command line; however, certain arguments (the ones in the second table) must be at the front of the list if they are used.

Here are the arguments allowed:

FILE
     Visit FILE using find-file.  See Visiting.

+LINENUM FILE
     Visit FILE using find-file, then go to line number LINENUM in it.

-load FILE
-l FILE
     Load a file FILE of Lisp code with the function load. See Lisp Libraries.

-funcall FUNCTION
-f FUNCTION
     Call Lisp function FUNCTION with no arguments.

-eval FUNCTION
     Interpret the next argument as a Lisp expression, and evaluate it. You must be very careful of the shell quoting here.

-insert FILE
-i FILE
     Insert the contents of FILE into the current buffer.  This is like what M-x insert-buffer does; see Misc File Ops.

-kill
     Exit from Emacs without asking for confirmation.

-version
-V
     Prints version information.  This implies -batch.

          % xemacs -version
          XEmacs 19.13 of Mon Aug 21 1995 on willow (usg-unix-v) [formerly Lucid Emacs]

-help
     Prints a summary of command-line options and then exits.

Command Line Arguments (Beginning of Line Only)
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The following arguments are recognized only at the beginning of the command line.  If more than one of them appears, they must appear in the order in which they appear in this table.

-t FILE
     Use FILE instead of the terminal for input and output.  This implies the -nw option, documented below.

-batch
     Run Emacs in batch mode, which means that the text being edited is not displayed and the standard Unix interrupt characters such as C-z and C-c continue to have their normal effect.  Emacs in batch mode outputs to stderr only what would normally be printed in the echo area under program control.

     Batch mode is used for running programs written in Emacs Lisp from shell scripts, makefiles, and so on.  Normally the -l switch or -f switch will be used as well, to invoke a Lisp program to do the batch processing.

     -batch implies -q (do not load an init file).  It also causes Emacs to kill itself after all command switches have been processed.  In addition, auto-saving is not done except in buffers for which it has been explicitly requested.

-nw
     Start up XEmacs in TTY mode (using the TTY XEmacs was started from), rather than trying to connect to an X display.  Note that this happens automatically if the DISPLAY environment variable is not set.

-debug-init
     Enter the debugger if an error in the init file occurs.

-debug-paths
     Displays information on how XEmacs constructs the various paths into its hierarchy on startup.  (See also Startup Paths.)

-unmapped
     Do not map the initial frame.  This is useful if you want to start up XEmacs as a server (e.g. for gnuserv screens or external client widgets).

-no-init-file
-q
     Do not load your Emacs init file ~/.emacs.

-no-site-file
     Do not load the site-specific init file lisp/site-start.el.

-no-autoloads
     Do not load global symbol files (auto-autoloads) at startup. This implies -vanilla.

-no-early-packages
     Do not process early packages.  (For more information on startup issues concerning the package system, see Startup Paths.)

-vanilla
     This is equivalent to -q -no-site-file -no-early-packages.

-user-init-file FILE
     Load FILE as your Emacs init file instead of ~/.emacs.

-user-init-directory DIRECTORY
     Use DIRECTORY as the location of your early package hierarchies and the various user-specific initialization files.

-user USER
-u USER
     Equivalent to -user-init-file ~USER/.emacs -user-init-directory ~USER/.xemacs.

Note that the init file can get access to the command line argument values as the elements of a list in the variable command-line-args.  (The arguments in the second table above will already have been processed and will not be in the list.)  The init file can override the normal processing of the other arguments by setting this variable.

One way to use command switches is to visit many files automatically:

     xemacs *.c

passes each .c file as a separate argument to Emacs, so that Emacs visits each file (see Visiting).

Here is an advanced example that assumes you have a Lisp program file called hack-c-program.el which, when loaded, performs some useful operation on the current buffer, expected to be a C program.

     xemacs -batch foo.c -l hack-c-program -f save-buffer -kill > log

Here Emacs is told to visit foo.c, load hack-c-program.el (which makes changes in the visited file), save foo.c (note that save-buffer is the function that C-x C-s is bound to), and then exit to the shell from which the command was executed.  -batch guarantees there will be no problem redirecting output to log, because Emacs will not assume that it has a display terminal to work with.

Command Line Arguments (for XEmacs Under X)
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If you are running XEmacs under X, a number of options are available to control color, border, and window title and icon name:

-title TITLE
-wn TITLE
-T TITLE
     Use TITLE as the window title. This sets the frame-title-format variable, which controls the title of the X window corresponding to the selected frame.  This is the same format as mode-line-format.

-iconname TITLE
-in TITLE
     Use TITLE as the icon name. This sets the frame-icon-title-format variable, which controls the title of the icon corresponding to the selected frame.

-mc COLOR
     Use COLOR as the mouse color.

-cr COLOR
     Use COLOR as the text-cursor foreground color.

-private
     Install a private colormap for XEmacs.

In addition, XEmacs allows you to use a number of standard Xt command line arguments.

-background COLOR
-bg COLOR
     Use COLOR as the background color.

-bordercolor COLOR
-bd COLOR
     Use COLOR as the border color.

-borderwidth WIDTH
-bw WIDTH
     Use WIDTH as the border width.

-display DISPLAY
-d DISPLAY
     When running under the X window system, create the window containing the Emacs frame on the display named DISPLAY.

-foreground COLOR
-fg COLOR
     Use COLOR as the foreground color.

-font NAME
-fn NAME
     Use NAME as the default font.

-geometry SPEC
-geom SPEC
-g SPEC
     Use the geometry (window size and/or position) specified by SPEC.

-iconic
     Start up iconified.

-rv
     Bring up Emacs in reverse video.

-name NAME
     Use the resource manager resources specified by NAME. The default is to use the name of the program (argv[0]) as the resource manager name.

-xrm
     Read something into the resource database for this invocation of Emacs only.