@node Command Switches, Basic, Exiting, Top
@section Command Line Switches and Arguments
@cindex command line arguments
@cindex arguments (from shell)

  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:
@itemize @bullet
@item 
Command line arguments that you can always use
@item 
Command line arguments that have to appear at the beginning of the
argument list
@item
Command line arguments that are only relevant if you are running XEmacs
under X
@end itemize

@subsection Command Line Arguments for Any Position
 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:

@table @samp
@item @var{file}
Visit @var{file} using @code{find-file}.  @xref{Visiting}.

@item +@var{linenum} @var{file}
Visit @var{file} using @code{find-file}, then go to line number
@var{linenum} in it.

@item -load @var{file}
@itemx -l @var{file}
Load a file @var{file} of Lisp code with the function @code{load}.
@xref{Lisp Libraries}.

@item -funcall @var{function}
@itemx -f @var{function}
Call Lisp function @var{function} with no arguments.

@item -eval @var{function}
Interpret the next argument as a Lisp expression, and evaluate it.
You must be very careful of the shell quoting here.

@item -insert @var{file}
@itemx -i @var{file}
Insert the contents of @var{file} into the current buffer.  This is like
what @kbd{M-x insert-buffer} does; @xref{Misc File Ops}.

@item -kill
Exit from Emacs without asking for confirmation.

@item -version
Prints version information.  This implies @samp{-batch}.

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

@item -help
Prints a summary of command-line options and then exits.
@end table

@subsection Command Line Arguments (Beginning of Line Only)
  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.

@table @samp
@item -t @var{file}
Use @var{file} instead of the terminal for input and output.  This
implies the @samp{-nw} option, documented below.

@cindex batch mode
@item -batch
Run Emacs in @dfn{batch mode}, which means that the text being edited is
not displayed and the standard Unix interrupt characters such as
@kbd{C-z} and @kbd{C-c} continue to have their normal effect.  Emacs in
batch mode outputs to @code{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 @samp{-l} switch or
@samp{-f} switch will be used as well, to invoke a Lisp program to do
the batch processing.

@samp{-batch} implies @samp{-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.

@item -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 @samp{DISPLAY} environment variable is not set.

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

@item -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).

@item -no-init-file
@itemx -q
Do not load your Emacs init file @file{~/.emacs}.

@item -no-site-file
Do not load the site-specific init file @file{lisp/site-start.el}.

@item -user @var{user}
@itemx -u @var{user}
Load @var{user}'s Emacs init file @file{~@var{user}/.emacs} instead of
your own.
@end table

@vindex command-line-args
  Note that the init file can get access to the command line argument
values as the elements of a list in the variable
@code{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:

@example
xemacs *.c
@end example

@noindent
passes each @code{.c} file as a separate argument to Emacs, so that
Emacs visits each file (@pxref{Visiting}).

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

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

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

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

@table @samp
@item -title @var{title}
@itemx -wn @var{title}
@itemx -T @var{title}
Use @var{title} as the window title. This sets the
@code{frame-title-format} variable, which controls the title of the X
window corresponding to the selected frame.  This is the same format as
@code{mode-line-format}.

@item -iconname @var{title}
@itemx -in @var{title}
Use @var{title} as the icon name. This sets the
@code{frame-icon-title-format} variable, which controls the title of
the icon corresponding to the selected frame.

@item -mc @var{color}
Use @var{color} as the mouse color.

@item -cr @var{color}
Use @var{color} as the text-cursor foreground color.
@end table

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

@table @samp

@item -background @var{color}
@itemx -bg @var{color}
Use @var{color} as the background color.

@item -bordercolor @var{color}
@itemx -bd @var{color}
Use @var{color} as the border color.

@item -borderwidth @var{width}
@itemx -bw @var{width}
Use @var{width} as the border width.

@item -display @var{display}
@itemx -d @var{display}
When running under the X window system, create the window containing the
Emacs frame on the display named @var{display}.

@item -foreground @var{color}
@itemx -fg @var{color}
Use @var{color} as the foreground color.

@item -font @var{name}
@itemx -fn @var{name}
Use @var{name} as the default font.

@item -geometry @var{spec}
@itemx -geom @var{spec}
@itemx -g @var{spec}
Use the geometry (window size and/or position) specified by @var{spec}.

@item -iconic
Start up iconified.

@item -rv
Bring up Emacs in reverse video.

@item -name @var{name}
Use the resource manager resources specified by @var{name}.
The default is to use the name of the program (@code{argv[0]}) as
the resource manager name.

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

@end table