Command Line Options and Arguments
**********************************

GNU Emacs supports command line arguments to request various actions when invoking Emacs.  These are for compatibility with other editors and for sophisticated activities.  We don't recommend using them for ordinary editing.

Arguments that are not options specify files to visit.  Emacs visits the specified files while it starts up.  (The last file name on your command line is the one you see displayed, but the rest are all there in other buffers.)

You can use options to specify other things, such as the size and position of the Emacs window if you are running it under the X Window System.  A few arguments support advanced usage, like running Lisp functions on files in batch mode.

There are two kinds of options: ordinary options and initial options.  Ordinary options can appear in any order and can be intermixed with file names to visit.  These and file names are called ordinary arguments.  Emacs processes all of these in the order they are written.  Initial options must come at the beginning of the command line.

Ordinary Arguments
==================

Here is a table of the ordinary arguments and options:

FILE
     Visit FILE using find-file.  See Visiting.

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

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

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

-insert 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.

Initial Options
===============

The initial options are recognized only at the beginning of the command line.  If you use more than one of them, they must appear in the order that they appear in this table.

-t DEVICE
     Use DEVICE as the device for terminal input and output.

-d DISPLAY
     When running with the X Window System, use the display named DISPLAY to make the window that serves as Emacs's terminal.

-nw
     Don't communicate directly with X, disregarding the DISPLAY environment variable even if it is set.  -nw stands for ``non-window.''

-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 option or -f option 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 options have been processed.  In addition, auto-saving is not done except in buffers for which it has been explicitly requested.

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

-u USER
-user USER
     Load USER's Emacs init file ~USER/.emacs instead of your own.

-debug-init
     Enable the Emacs Lisp debugger for errors in the init file.

The init file can get access to the values of the command line arguments as the elements of a list in the variable command-line-args.  (The list contains only the arguments from the first table above.  Emacs processes the arguments from the second table before building the list.)  The init file can override the normal processing of the other arguments by setting this variable.

Command Argument Example
========================

Here is an example of using Emacs with arguments and options.  It assumes you have a Lisp program file called hack-c.el which, when loaded, performs some useful operation on current buffer, expected to be a C program.

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

This says to visit foo.c, load hack-c.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 that this command was done with.  The initial option -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.

Resuming Emacs with Arguments
=============================

You can specify ordinary arguments for Emacs when you resume it after a suspension.  To prepare for this, put the following code in your .emacs file (see Hooks):

     (add-hook 'suspend-hook 'resume-suspend-hook)

As further preparation, you must execute the shell script emacs.csh (if you use CSH as your shell) or emacs.bash (if you use BASH as your shell).  These scripts define an alias named edit, which will resume Emacs giving it new command line arguments such as files to visit.

Only ordinary arguments work properly when you resume Emacs.  Initial arguments are not recognized.  It's too late to execute them anyway.

Note that resuming Emacs (with or without arguments) must be done from within the shell that is the parent of the Emacs job.  This is why edit is an alias rather than a program or a shell script.  It is not possible to implement a resumption command that could be run from other subjobs of the shell; no way to define a command that could be made the value of EDITOR, for example.  Therefore, this feature does not take the place of the the Emacs Server feature.  See Emacs Server.

The aliases use the Emacs Server feature if you appear to have a server Emacs running.  However, they cannot determine this with complete accuracy.  They may think that a server is still running when in actuality you have killed that Emacs, because the file /tmp/.esrv... still exists.  If this happens, find that file and delete it.

Environment Variables
=====================

This appendix describes how Emacs uses environment variables.  An environment variable is a string passed from the operating system to Emacs, and the collection of environment variables is known as the environment.

Because environment variables come from the operating system there is no general way to set them; it depends on the operating system and especially the shell that you are using.  If, e.g., you are using the csh or tcsh shell and want to set the environment variable ESHELL to /bin/tcsh you would give the command

     setenv ESHELL /bin/tcsh

Environment variables are case sensitive and it is conventional to use upper case letters only.

When Emacs is set-up to use the X windowing system, it inherits the use of a large number of environment variables from the X library.  See the X documentation for more information.

General Variables
-----------------

AUTHORCOPY
     The name of a file used to archive news articles posted with the `gnus' package.

CDPATH
     Used by the cd command.

DOMAINNAME
     The name of the internet domain that the machine running Emacs is located in.  Used by the `gnus' package.

EMACSDATA
     Used to initialize the variable data-directory used to locate the architecture-independent files that come with Emacs.  Setting this variable overrides the setting in paths.h when Emacs was built.

EMACSLOADPATH
     A colon-separated list of directories from which to load Emacs Lisp files.  Setting this variable overrides the setting in paths.h when Emacs was built.

EMACSLOCKDIR
     The directory that Emacs places lock files --- files used to protect users from editing the same files simultaneously.  Setting this variable overrides the setting in paths.h when Emacs was built.

EMACSPATH
     The location of Emacs-specific binaries.  Setting this variable overrides the setting in paths.h when Emacs was built.

ESHELL
     Used for shell-mode to override the SHELL environment variable.

HISTFILE
     The name of the file that shell commands are saved in between logins. This variable defaults to ~/.history if you use (t)csh as shell, to ~/.bash_history if you use bash, to ~/.sh_history if you use ksh, and to ~/.history otherwise.

HOME
     The location of the user's files in the directory tree; used for expansion of file names starting with a tilde (~).

HOSTNAME
     The name of the machine that Emacs is running on.

INCPATH
     A colon-separated list of directories.  Used by the `complete' package to search for files.

INFOPATH
     A colon separated list of directories holding info files.  Setting this variable overrides the setting in paths.el when Emacs was built.

LOGNAME
     The user's login name.  See also USER.

MAIL
     The name of the user's system mail box.

MAILRC
     Name of file containing mail aliases.  Defaults to ~/.mailrc.

MH
     Name of setup file for the mh system.  Defaults to ~/.mh_profile.

NAME
     The real-world name of the user.

NNTPSERVER
     The name of the news server.  Used by the `mh' and `gnus' packages.

ORGANIZATION
     The name of the organization to which you belong.  Used for setting the `Organization:' header in your posts from the `gnus' package.

PATH
     A colon-separated list of directories in which executeables reside. This variable is used to set the Emacs Lisp variable exec-path which you should consider to use instead.

PWD
     If set, this should be the default directory when Emacs was started.

SAVEDIR
     The name of a directory in which news articles are saved by default. Used by the `gnus' package.

SHELL
     The name of an interpreter used to parse and execute programs run from inside Emacs.

TERM
     The name of the terminal that Emacs is running on.  The variable must be set unless Emacs is run in batch mode.

TERMCAP
     The name of the termcap library file describing how to program the terminal specified by the TERM variable.  This defaults to /etc/termcap.

TMPDIR
     Used by the `emerge' package as a prefix for temporary files.

TZ
     This specifies the current time zone and possibly also daylight savings information.

USER
     The user's login name.  See also LOGNAME.

VERSION_CONTROL
     Used to initialize the version-control variable, which see.

MS-DOS Variables
----------------

Some of the variables that Emacs uses make little or no sense in an single-user setting as provided by MS-DOS machines.  Nevertheless parts of Emacs need those variables so many of them have defaults for MS-DOS.

The standard command interpreter (``shell'') for MS-DOS disregards case of environment variables and only lets you set and delete variables with upper case names.  For this reason it is possible that some existing programs may disregard case of environment variables.  On the other hand, programs that execute other programs may choose to provide mixed or lower case variables though this is seldom seen.  One exception from this rule is the use of variables _argc, _argv0, _argv1, ... to work around the 127 character limit on the command line imposed by MS-DOS.  Emacs, when built with the Gnu C compiler, understands this method and uses it when running other GCC compiled programs.

COMSPEC
     The name of the MS-DOS command interpreter in use.  This is used to make a default value for the SHELL environment variable.

EMACSPATH
     Defaults to ~/bin expanded.

HOME
     The variable defaults to the directory from which Emacs was started, possibly with a /bin suffix removed.

NAME
     This variable default to whatever the USER variable is.

PATH
     As the current directory is always searched for commands by the standard command interpreter, the current directory is added to the path. Semicolons, not colons, are used to separate elements.

TEMP
     Directory name of place to put temporary files.

TMP
     See TEMP

TERM
     The variable defaults to internal, a very fast terminal emulation built into Emacs.  When the internal terminal is used no termcap file is needed.

TZ
     This variable defaults to an estimate derived from the MS-DOS country code.  See the file msdos.c for details.

USER
     The variable defaults to root because all MS-DOS users have root privileges on their system.

Misc Variables
--------------

These variables are used only in rare setups:

USE_DOMAIN_ACLS
     Used for Apollo machines to enable access control lists.

WINDOW_GFX
     Used when initializing the Sun windows system.

Specifying the Display Name
===========================

The environment variable DISPLAY tells all X clients where to display their windows.  Its value is set up by default in ordinary circumstances, when you start an X server and run jobs locally. Occasionally you may need to specify the display yourself; for example, if you do a remote login and want to run a client program remotely, displaying on your local screen.

With Emacs, the main reason people change the default display is to let them log into another system, run Emacs on that system, but have the window displayed at their local terminal.  You might need to use login to another system because the files you want to edit are there, or because the Emacs executable file you want to run is there.

The syntax of the DISPLAY environment variable is:

     HOST:DISPLAY.SCREEN

where HOST is the host name of the X Window System server machine, DISPLAY is an arbitrarily-assigned number that distinguishes your server (X terminal) from other servers on the same machine, and SCREEN is a rarely-used field that allows an X server to control multiple terminal screens.  The period and the SCREEN field are optional.  If included, SCREEN is usually zero.

If your host is named glasperle and your server is the first (or perhaps the only) server listed in the configuration, your DISPLAY is glasperle:0.0.

You can specify the display name explicitly when you run Emacs, either by changing the DISPLAY variable, or with the option -d DISPLAY or -display DISPLAY.  These are initial options; they must come at the beginning of the command line. See Initial Options.  Here is an example:

     emacs -display glasperle:0 &

You can inhibit the direct use of X with the -nw option.  This is also an initial option.  This option tells Emacs to display using ordinary ASCII on its controlling terminal.

Sometimes, security arrangements prevent a program on a remote system from displaying on your local system.  In this case, trying to run Emacs produces messages like:

     Xlib:  connection to "glasperle:0.0" refused by server

You might be able to overcome this problem by using the xhost command on the local system to give permission for access from your remote machine.

Font Specification Options
==========================

By default, Emacs displays text in the font named 9x15, which makes each character nine pixels wide and fifteen pixels high.  You can specify a different font on your command line through the option -fn NAME.

-fn NAME
     Use font NAME as the default font.

-font NAME
     -font is an alias for -fn.

Here is how to specify the font 6x13:

     emacs -fn 6x13 &

You can also do this in your .Xdefaults file:

     emacs.font:      6x13

Use only fixed width fonts---that is, fonts in which all characters have the same width.  Emacs cannot yet handle display properly for variable width fonts.  Fixed width fonts include the one named fixed, and fonts with names in the form NxN, such as 6x13, 8x13, and 9x15.  Under the font-naming conventions in X11 Release 4 or later, any font with m or c in the eleventh field of the name is a fixed width font.

Here's how to use the xlsfonts program to list all the fixed width fonts available on your system:

     xlsfonts -fn '*x*'
     xlsfonts -fn '*-*-*-*-*-*-*-*-*-*-*-m*'
     xlsfonts -fn '*-*-*-*-*-*-*-*-*-*-*-c*'

To see what a particular font looks like, use the xfd command. For example:

     xfd -fn 6x13

displays the entire font 6x13.

While running Emacs, you can set the font of the current frame (see Frame Parameters) or for a specific kind of text (see Faces).

Window Color Options
====================

On a color display, you can specify which color to use for various parts of the Emacs display.  To find out what colors are available on your system, look at the /usr/lib/X11/rgb.txt file.  If you do not specify colors, the default for the background is white and the default for all other colors is black.

On a monochrome (black and white) display, the foreground is black, the background is white, and the border is grey.

Here is a list of the options for specifying colors:

-fg COLOR
     Specify the foreground color.

-bg COLOR
     Specify the background color.

-bd COLOR
     Specify the color of the border of the X window.

-cr COLOR
     Specify the color of the Emacs cursor which indicates where point is.

-ms COLOR
     Specify the color for the mouse cursor when the mouse is in the Emacs window.

-r
     Reverse video---swap the foreground and background colors.

For example, to use a coral mouse cursor and a slate blue text cursor, enter:

     emacs -ms coral -cr 'slate blue' &

You can reverse the foreground and background colors through the -r option or with the X resource reverseVideo.

Options for Window Geometry
===========================

The -geometry option controls the size and position of the initial Emacs frame.  Here is the format for specifying the window geometry:

-geometry WIDTHxHEIGHT{+-}XOFFSET{+-}YOFFSET
     Specify window size WIDTH and HEIGHT (measured in character columns and lines), and positions XOFFSET and YOFFSET (measured in pixels).

A positive XOFFSET specifies the distance from the left side of the screen, a negative XOFFSET specifies the distance from the right side of the screen, a positive YOFFSET specifies the distance from the top of the screen, and a negative YOFFSET specifies the distance from the bottom of the screen.

Emacs uses the same units as xterm does to interpret the geometry. The WIDTH and HEIGHT are measured in characters, so a large font creates a larger frame than a small font.  The XOFFSET and YOFFSET are measured in pixels.

Since the mode line and the echo area occupy the last 2 lines of the frame, the height of the initial text window is 2 less than the height specified in your geometry.

You do not have to specify all of the fields in the geometry specification.

If you omit both XOFFSET and YOFFSET, the window manager decides where to put the Emacs frame, possibly by letting you place it with the mouse.  For example, 164x55 specifies a window 164 columns wide, enough for two ordinary width windows side by side, and 55 lines tall.

The default width for Emacs is 80 characters and the default height is 24 characters.  You can omit either the width or the height or both.  If you start the geometry with an integer, Emacs interprets it as the width.  If you start with an x followed by an integer, Emacs interprets it as the height.  Thus, 81 specifies just the width; x45 specifies just the height.

If you start with + or -, that introduces an offset, which means both sizes are omitted.  Thus, -3 specifies the XOFFSET only.  (If you give just one offset, it is always XOFFSET.)  +3-3 specifies both the XOFFSET and the YOFFSET, placing the frame near the bottom left of the screen.

You can specify a default for any or all of the fields in .Xdefaults file, and then override selected fields through a -geometry option.

Internal and External Borders
=============================

An Emacs frame has an internal border and an external border.  The internal border is an extra strip of the background color around all four edges of the frame.  Emacs itself adds the internal border.  The external border is added by the window manager outside the internal border; it may contain various boxes you can click on to move or iconify the window.

-ib WIDTH
     Specify WIDTH as the width of the internal border.

-bw WIDTH
     Specify WIDTH as the width of the main border.

When you specify the size of the frame, that does not count the borders.  The frame's position is measured from the outside edge of the external border.

Use the -ib N option to specify an internal border N pixels wide.  The default is 1.  Use -bw N to specify the width of the external border (though the window manager may not pay attention to what you specify).  The default width of the external border is 2.

Icons
=====

Most window managers allow the user to ``iconify'' a frame, removing it from sight, and leaving a small, distinctive ``icon'' window in its place.  Clicking on the icon window will make the original frame visible again.  If a user has many clients running at once, they can avoid cluttering up their screen by iconifying all but the clients currently in use.

-i
-itype
     Use a picture of a gnu as the Emacs icon.

-iconic
     Start Emacs in iconified state.

The -i and -itype option tells Emacs to use an icon window containing a picture of the GNU gnu.  If omitted, Emacs lets the window manager choose what sort of icon to use---usually just a small rectangle containing the frame's title.

The -iconic option tells Emacs to begin running as an icon, rather than opening a frame right away.  In this situation, the icon window provides only indication that Emacs has started; the usual text frame doesn't appear until you de-iconify it.

X Resources
===========

Programs running under the X Window System organize their user options under a hierarchy of classes and resources.  You can specify default values for these options in your X resources file, usually named ~/.Xdefaults.

Each line in the file specifies a value for one option or for a collection of related options, for one program or for several programs (perhaps even all programs).

Programs define named resources with particular meanings.  They also define how to group resources into named classes.  For instance, in Emacs, the internalBorder resource controls the width of the internal border, and the borderWidth resource controls the width of the external border.  Both of these resources are part of the BorderWidth class.  Case distinctions are significant in these names.

In ~/.Xdefaults, you can specify a value for a single resource on one line, like this:

     emacs.borderWidth: 2

Or you can use a class name to specify the same value for all resources in that class.  Here's an example:

     emacs.BorderWidth: 2

If you specify a value for a class, it becomes the default for all resources in that class.  You can specify values for individual resources as well; these override the class value, for those particular resources.  Thus, this example specifies 2 as the default width for all borders, but overrides this value with 4 for the external border:

     emacs.Borderwidth: 2
     emacs.borderwidth: 4

The order in which the lines appear in the file does not matter. Also, command-line options always override the X resources file.

The string emacs in the examples above is also a resource name.  It actually represents the name of the executable file that you invoke to run Emacs.  If Emacs is installed under a different name, it looks for resources under that name instead of emacs.

-name NAME
     Use NAME as the title of the initial frame and as the name for looking up resource values.

-rn NAME
     Use NAME as the name for looking up resource values.

If you specify the option -name NAME, Emacs uses NAME instead of emacs to look up all of its option values in the X resource file.  This option also specifies the title for the initial frame.  The option -rn NAME specifies just the name for use in resources and not the frame title.  If you want to specify both the resource name and the frame title separately, use -name TITLE -rn RESNAME.

The resources that name Emacs invocations also belong to a class; its name is Emacs.  To specify options for all Emacs jobs, no matter what name is used to run them, write Emacs instead of emacs, like this:

     Emacs.BorderWidth: 2
     Emacs.borderWidth: 4

You can specify a string of additional resource values for Emacs to use with the command line option -xrm DATA.  The text DATA should have the same format that you would use inside a file of X resources.  Resources specified this way take precedence over all others.

The following table lists the resource names that designate options for Emacs, each with the class that it belongs to:

background (class Background)
     Background color name.

bitmapIcon (class BitmapIcon)
     Use a bitmap icon (a picture of a GNU) if on, let the window manager choose an icon if off.

borderColor (class BorderColor)
     Color name for external border.

borderWidth (class BorderWidth)
     Width in pixels of external border.

cursorColor (class Foreground)
     Color name for text cursor (point).

font (class Font)
     Font name for text.

foreground (class Foreground)
     Color name for text.

geometry (class Geometry)
     Window size and position.  Be careful not to specify this resource as emacs*geometry, because that may affect individual menus as well as the Emacs frame itself.

iconName (class Title)
     Name to display in icon.

internalBorder (class BorderWidth)
     Width in pixels of internal border.

paneFont (class Font)
     Font name for menu pane titles.

pointerColor (class Foreground)
     Color of mouse cursor.

reverseVideo (class ReverseVideo)
     Switch foreground and background default colors if on, use colors as specified if off.

selectionFont (class Font)
     Font name for menu items.

title (class Title)
     Name to display in title bar of initial Emacs frame.

If the Emacs installed at your site was built to use an X toolkit, then the menu bar is a separate widget and has its own resources.  Their names start with shell.pane.menubar; specify them like this:

     Emacs.shell.pane.menubar.RESOURCE:  VALUE

For example, to specify the font 8x16 for the menu bar items, write this:

     Emacs.shell.pane.menubar.font:  8x16

or, for short, like this:

     Emacs*menubar.font:  8x16

Resources for toolkit popup menus have shell.menu.popup, in like fashion.  For example, to specify the font 8x16 for the menu bar items, write this:

     Emacs.shell.menu.popup.font:	8x16

Here is a list of the specific resources for menu bars and popup menus:

font
     The font for menu item text.

foreground
     The color of the foreground.

buttonForeground
     The color of the menu panes.

horizontalSpacing
     The horizontal spacing in pixels between items.  Default is 3.

verticalSpacing
     The vertical spacing in pixels between items.  Default is 1.

arrowSpacing
     The horizontal spacing between the arrow (which indicates a submenu) and the associated text.  Default is 10.

shadowThickness
     The thickness of shadow line around the widget.

Here are resources for controlling the appearance of particular faces (see Faces):

FACE.attributeFont
     The font for face FACE.

FACE.attributeForeground
     The foreground color for face FACE.

FACE.attributeBackground
     The background color for face FACE.

FACE.attributeUnderline
     The underline flag for face FACE.