Appendix A Command Line 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 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.

You can use options to specify various other 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.

There are two kinds of options: initial options and ordinary options. Initial options must come at the beginning of the command line, in a particular order. Ordinary options come afterward; they 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.

A.1 Ordinary Arguments

Here is a table of the ordinary arguments and options:

‘file’

Visit file using find-file. @xref{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. @xref{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-file does; @xref{Misc File Ops}.

‘-kill’

Exit from Emacs without asking for confirmation.

A.2 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 terminal 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’.

‘-no-site-file’

Do not load ‘site-start.el’. (This file is normally loaded before ‘~/.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 access the values of the command line arguments as the elements of a list in the variable command-line-args. (The list contains only the ordinary arguments; Emacs processes the initial arguments before building the list.) The init file can override the normal processing of the ordinary arguments by setting this variable.

A.3 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.

A.4 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 (@pxref{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. @xref{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.

A.5 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. 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.

A.5.1 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 (‘~’). On MS-DOS, it defaults to the directory from which Emacs was started, with ‘/bin’ removed from the end if it was present.

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. This defaults to ‘~/.mailrc’.

MH

Name of setup file for the mh system. This 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 executables reside. (On MS-DOS, it is semicolon-separated instead.) 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. On MS-DOS, it defaults to ‘internal’, which specifies a built-in terminal emulation that handles the machine’s own display.

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. On MS-DOS, the default is based on country code; see the file ‘msdos.c’ for details.

USER

The user’s login name. See also LOGNAME. On MS-DOS, this defaults to ‘root’.

VERSION_CONTROL

Used to initialize the version-control variable (@pxref{Backup Names}).

A.5.2 Misc Variables

These variables are used only on particular configurations:

COMSPEC

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

NAME

On MS-DOS, this variable defaults to the value of the USER variable.

TEMP

TMP

On MS-DOS, these specify the name of the directory for storing temporary files in.

USE_DOMAIN_ACLS

Used for Apollo machines to enable access control lists.

WINDOW_GFX

Used when initializing the Sun windows system.

A.6 Specifying the Display Name

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’. These are initial options; they must come at the beginning of the command line. See section 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 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.

A.7 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’.

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 wild card 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

family

This is the name of the font family–for example, ‘courier’.

weight

This is normally ‘bold’, ‘medium’ or ‘light’. Other words may appear here in some font names.

slant

This is ‘r’ (roman), ‘i’ (italic), ‘o’ (oblique), ‘ri’ (reverse italic), or ‘ot’ (other).

widthtype

This is normally ‘condensed’, ‘extended’, ‘semicondensed’ or ‘normal’. Other words may appear here in some font names.

style

This is an optional additional style name. Usually it is empty—most long font names have two hyphens in a row at this point.

pixels

This is the font height, in pixels.

height

This is the font height on the screen, measured in printer’s points (approximately 1/72 of an inch), times ten. For a given vertical resolution, height and pixels are proportional; therefore, it is common to specify just one of them and use ‘*’ for the other.

horiz

This is the horizontal resolution, in pixels per inch, of the screen for which the font is intended.

vert

This is the vertical resolution, in dots per inch, of the screen for which the font is intended. Normally the resolution of the fonts on your system is the right value for your screen; therefore, you normally specify ‘*’ for this and horiz.

spacing

This is ‘m’ (monospace), ‘p’ (proportional) or ‘c’ (character cell). Emacs can use ‘m’ and ‘c’ fonts.

width

This is the average character width, in pixels, times ten.

charset

This is the character set that the font depicts. Normally you should use ‘iso8859-1’.

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 (@pxref{Frame Parameters}) or for a specific kind of text (@pxref{Faces}).

A.8 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’.

A.9 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. In non-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 through a ‘-geometry’ option.

A.10 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.

A.11 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 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.

‘-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 deiconify it.

A.12 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 (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’.

When Emacs creates a new frame, it 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. It is also used (instead of the Emacs executable’s name) to look up all the resources for that frame. The option ‘-name’ specifies a frame title for the initial frame. Subsequent frames normally have no frame title, but Lisp programs can specify a title when they create frames.

‘-name name’

Use name as the title of the initial frame.

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’. 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 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)

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 the external border.

borderWidth (class BorderWidth)

Width in pixels of the 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 the icon.

internalBorder (class BorderWidth)

Width in pixels of the internal border.

paneFont (class Font)

Font name for menu pane titles, in non-toolkit versions of Emacs.

pointerColor (class Foreground)

Color of the 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 pop-up menu items, in non-toolkit versions of Emacs. (Toolkit versions, use emacs.shell.menu.popup.font instead—see below.)

title (class Title)

Name to display in the title bar of the 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

Font for menu item text.

foreground

Color of the foreground.

background

Color of the background.

buttonForeground

In the menu bar, the color of the foreground for a selected item.

horizontalSpacing

Horizontal spacing in pixels between items. Default is 3.

verticalSpacing

Vertical spacing in pixels between items. Default is 1.

arrowSpacing

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

shadowThickness

Thickness of shadow line around the widget.

Here are resources for controlling the appearance of particular faces (@pxref{Faces}):

face.attributeFont

Font for face face.

face.attributeForeground

Foreground color for face face.

face.attributeBackground

Background color for face face.

face.attributeUnderline

Underline flag for face face.

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