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 starting with `-' are options. Other arguments specify files to visit. Emacs visits the specified files while it starts up. The last file name on your command line becomes the current buffer; the other files are also present in other buffers. As usual, the special argument `--' says that all subsequent arguments are file names, not options, even if they start with `-'.
Emacs command options can specify many things, such as the size and position of the X window Emacs uses, its colors, and so on. A few options support advanced usage, such as running Lisp functions on files in batch mode. The sections of this chapter describe the available options, arranged according to their purpose.
There are two ways of writing options: the short forms that start with a single `-', and the long forms that start with `--'. For example, `-d' is a short form and `--display' is the corresponding long form.
The long forms with `--' are easier to remember, but longer to type. However, you don't have to spell out the whole option name; any unambiguous abbreviation is enough. When a long option takes an argument, you can use either a space or an equal sign to separate the option name and the argument. Thus, you can write either `--display sugar-bombs:0.0' or `--display=sugar-bombs:0.0'. We recommend an equal sign because it makes the relationship clearer, and the tables below always show an equal sign.
Most options specify how to initialize Emacs, or set parameters for the Emacs session. We call them initial options. A few options specify things to do: for example, load libraries, call functions, or exit Emacs. These are called action options. These and file names together are called action arguments. Emacs processes all the action arguments in the order they are written.
Here is a table of the action arguments and options:
find-file. See section Visiting Files.
find-file, then go to line number
linenum in it.
load.
See section Libraries of Lisp Code for Emacs. The library can be found either in the current
directory, or in the Emacs library search path as specified
with EMACSLOADPATH (see section General Variables).
The init file can access the values of the action arguments as the
elements of a list in the variable command-line-args. The init
file can override the normal processing of the action arguments, or
define new ones, by reading and setting this variable.
The initial options specify parameters for the Emacs session. This section describes the more general initial options; some other options specifically related to X Windows appear in the following sections.
Some initial options affect the loading of init files. The normal actions of Emacs are to first load `site-start.el' if it exists, then your own init file `~/.emacs' if it exists, and finally `default.el' if it exists; certain options prevent loading of some of these files or substitute other files for them.
DISPLAY
environment variable even if it is set.
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.
EMACS_UNIBYTE has the same effect.
EMACS_UNIBYTE, so that Emacs
uses multibyte characters by default, as usual.
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 the current buffer, expected to be a C program.
emacs -batch foo.c -l hack-c -f save-buffer >& 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 back to the shell (because of `-batch'). `-batch'
also guarantees there will be no problem redirecting output to
`log', because Emacs will not assume that it has a display terminal
to work with.
You can specify action arguments for Emacs when you resume it after a suspension. To prepare for this, put the following code in your `.emacs' file (see section Hooks):
(add-hook 'suspend-hook 'resume-suspend-hook) (add-hook 'suspend-resume-hook 'resume-process-args)
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 action 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 Emacs Server feature (see section Using Emacs as a 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.
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. Environment variable names are case sensitive and it is conventional to use upper case letters only.
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. For example, here's how to set
the environment variable ORGANIZATION to `not very much'
using bash:
export ORGANIZATION="not very much"
and here's how to do it in csh or tcsh:
setenv ORGANIZATION "not very much"
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.
AUTHORCOPY
CDPATH
cd command to search for the directory you specify,
when you specify a relative directory name.
DOMAINNAME
EMACS_UNIBYTE
EMACSDATA
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
EMACSLOCKDIR
EMACSPATH
ESHELL
SHELL environment variable.
HISTFILE
HOME
HOSTNAME
INCPATH
complete package
to search for files.
INFOPATH
LANG
LC_ALL
LC_CTYPE
LOGNAME
USER.
MAIL
MAILRC
MH
NAME
NNTPSERVER
ORGANIZATION
PATH
exec-path which you should consider
to use instead.
PWD
REPLYTO
mail-default-reply-to. See section Mail Header Fields.
SAVEDIR
SHELL
TERM
TERMCAP
TERM variable. This defaults to
`/etc/termcap'.
TMPDIR
TZ
USER
LOGNAME. On MS-DOS, this
defaults to `root'.
VERSION_CONTROL
version-control variable (see section Single or Numbered Backups).
These variables are used only on particular configurations:
COMSPEC
SHELL environment variable.
NAME
USER
variable.
TEMP
TMP
EMACSTEST
EMACSCOLORS
WINDOW_GFX
The environment variable DISPLAY tells all X clients, including
Emacs, 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.
For example, 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'. 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. It 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 this:
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.
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'.
Under X, each font has a long name which consists of eleven words or numbers, separated by dashes. Some fonts also have shorter nicknames---`9x15' is such a nickname. You can use either kind of name. You can use wildcard patterns for the font name; then Emacs lets X choose one of the fonts that match the pattern. Here is an example, which happens to specify the font whose nickname is `6x13':
emacs -fn "-misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1" &
You can also specify the font in your `.Xdefaults' file:
emacs.font: -misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1
A long font name has the following form:
-maker-family-weight-slant-widthtype-style... ...-pixels-height-horiz-vert-spacing-width-charset
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. Any font with `m' or `c' in the
spacing field of the long 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 section Setting Frame Parameters) or for a specific kind of text (see section Using Multiple Typefaces).
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 display, the foreground is black, the background is white, and the border is gray if the display supports that.
Here is a list of the options for specifying 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'.
The `-geometry' option controls the size and position of the initial Emacs frame. Here is the format for specifying the window geometry:
{+-} means either a plus sign or a minus sign. A plus
sign before xoffset means it is the distance from the left side of
the screen; a minus sign means it counts from the right side. A plus
sign before yoffset means it is the distance from the top of the
screen, and a minus sign there indicates the distance from the bottom.
The values xoffset and yoffset may themselves be positive or
negative, but that doesn't change their meaning, only their direction.
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. In non-X-toolkit versions of Emacs, the menu bar also takes one line of the specified number.
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 40 lines. 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 with a `--geometry' option.
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 `-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.
An Emacs frame may or may not have a specified title. The frame title, if specified, appears in window decorations and icons as the name of the frame. If an Emacs frame has no specified title, the default title is the name of the executable program (if there is only one frame) or the selected window's buffer name (if there is more than one frame).
You can specify a title for the initial Emacs frame with a command line option:
The `--name' option (see section X Resources) also specifies the title for the initial Emacs frame.
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 makes the frame itself appear again. If you have many clients running at once, you can avoid cluttering up the screen by iconifying most of the clients.
The `-i' or `--icon-type' 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 deiconify it.
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 (optionally even for 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'.
For consistency, `-name' also specifies the name to use for other resource values that do not belong to any particular frame.
The resources that name Emacs invocations also belong to a class; its name is `Emacs'. If you write `Emacs' instead of `emacs', the resource applies to all frames in all Emacs jobs, regardless of frame titles and regardless of the name of the executable file. Here is an example:
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 resources'. The text resources should have the same format that you would use inside a file of X resources. To include multiple resource specifications in data, put a newline between them, just as you would in a file. You can also use `#include "filename"' to include a file full of resource specifications. Resource values specified with `-xrm' take precedence over all other resource specifications.
The following table lists the resource names that designate options for Emacs, each with the class that it belongs to:
background (class Background)
bitmapIcon (class BitmapIcon)
borderColor (class BorderColor)
borderWidth (class BorderWidth)
cursorColor (class Foreground)
font (class Font)
foreground (class Foreground)
geometry (class Geometry)
iconName (class Title)
internalBorder (class BorderWidth)
menuBar (class MenuBar)
minibuffer (class Minibuffer)
paneFont (class Font)
pointerColor (class Foreground)
reverseVideo (class ReverseVideo)
verticalScrollBars (class ScrollBars)
selectionFont (class Font)
title (class Title)
Here are resources for controlling the appearance of particular faces (see section Using Multiple Typefaces):
face.attributeFont
face.attributeForeground
face.attributeBackground
face.attributeUnderline
If the Emacs installed at your site was built to use the X toolkit with the Lucid menu widgets, then the menu bar is a separate widget and has its own resources. The resource names contain `pane.menubar' (following, as always, the name of the Emacs invocation or `Emacs' which stands for all Emacs invocations). Specify them like this:
Emacs.pane.menubar.resource: value
For example, to specify the font `8x16' for the menu-bar items, write this:
Emacs.pane.menubar.font: 8x16
Resources for non-menubar toolkit pop-up menus have `menu*', in like fashion. For example, to specify the font `8x16' for the pop-up menu items, write this:
Emacs.menu*.font: 8x16
For dialog boxes, use `dialog' instead of `menu':
Emacs.dialog*.font: 8x16
Experience shows that on some systems you may need to add `shell.' before the `pane.menubar' or `menu*'. On some other systems, you must not add `shell.'.
Here is a list of the specific resources for menu bars and pop-up menus:
font
foreground
background
buttonForeground
horizontalSpacing
verticalSpacing
arrowSpacing
shadowThickness
If the Emacs installed at your site was built to use the X toolkit with the Motif widgets, then the menu bar is a separate widget and has its own resources. The resource names contain `pane.menubar' (following, as always, the name of the Emacs invocation or `Emacs' which stands for all Emacs invocations). Specify them like this:
Emacs.pane.menubar.subwidget.resource: value
Each individual string in the menu bar is a subwidget; the subwidget's name is the same as the menu item string. For example, the word `Files' in the menu bar is part of a subwidget named `emacs.pane.menubar.Files'. Most likely, you want to specify the same resources for the whole menu bar. To do this, use `*' instead of a specific subwidget name. For example, to specify the font `8x16' for the menu-bar items, write this:
Emacs.pane.menubar.*.fontList: 8x16
This also specifies the resource value for submenus.
Each item in a submenu in the menu bar also has its own name for X resources; for example, the `Files' submenu has an item named `Save Buffer'. A resource specification for a submenu item looks like this:
Emacs.pane.menubar.popup_*.menu.item.resource: value
For example, here's how to specify the font for the `Save Buffer' item:
Emacs.pane.menubar.popup_*.Files.Save Buffer.fontList: 8x16
For an item in a second-level submenu, such as `Check Message' under `Spell' under `Edit', the resource fits this template:
Emacs.pane.menubar.popup_*.popup_*.menu.resource: value
For example,
Emacs.pane.menubar.popup_*.popup_*.Spell.Check Message: value
It's impossible to specify a resource for all the menu-bar items without also specifying it for the submenus as well. So if you want the submenu items to look different from the menu bar itself, you must ask for that in two steps. First, specify the resource for all of them; then, override the value for submenus alone. Here is an example:
Emacs.pane.menubar.*.fontList: 8x16 Emacs.pane.menubar.popup_*.fontList: 8x16
For toolkit pop-up menus, use `menu*' instead of `pane.menubar'. For example, to specify the font `8x16' for the pop-up menu items, write this:
Emacs.menu*.fontList: 8x16
@medbreak Here is a list of the specific resources for menu bars and pop-up menus:
armColor
fontList
marginBottom
marginHeight
marginLeft
marginRight
marginTop
marginWidth
borderWidth
shadowThickness
bottomShadowColor
topShadowColor