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.

-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 stdout 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.

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 give 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.

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.  The -font option is a synonym 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.  You can reverse the foreground and background colors through the -r option or the reverseVideo resource.

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.

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

     emacs -ms coral -cr 'slate blue' &

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:

     WIDTHxHEIGHT{+-}XOFFSET{+-}YOFFSET

where WIDTH specifies the number of characters displayed on a line, HEIGHT specifies the number of lines displayed, 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 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.  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 omit both XOFFSET nor 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.

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.

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 -b N to specify the width of the external border (though the window manager may add to this on certain edges).  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.

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 look for resources under that name instead of emacs.

You can tell Emacs to use a different name instead of the name of the executable file, with the option -rn NAME.  Then that Emacs job uses NAME instead of Emacs to look up all of its option values in the X resource file.

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

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 kitchen sink icon 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.

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.