X resources

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Xresources is a user-level configuration dotfile, typically located at ~/.Xresources. It can be used to set X resources, which are configuration parameters for X client applications.

Among other things they can be used to:

Installation

Install the xorg-xrdb package.

Usage

Load resource file

Resources are stored in the X server, so have to only be read once. They are also accessible to remote X11 clients (such as those forwarded over SSH).

Load a resource file (such as the conventional .Xresources), replacing any current settings: 

$ xrdb ~/.Xresources

Load a resource file, and merge with the current settings: 

$ xrdb -merge ~/.Xresources
Note:
  • Most Display managers load the ~/.Xresources file on login.
  • The older ~/.Xdefaults file is read when an X11 program starts, but only if xrdb has not been used in the current session. [1]

xinitrc

If you are using a copy of the default xinitrc as your .xinitrc it already merges ~/.Xresources.

If you are using a custom .xinitrc add the following line: 

[[ -f ~/.Xresources ]] && xrdb -merge -I$HOME ~/.Xresources
Note: Do not background the xrdb command within ~/.xinitrc. Otherwise, programs launched after xrdb may look for resources before it has finished loading them.

Default settings

To see the default settings for your installed X11 applications, look in /usr/share/X11/app-defaults/.

Detailed information on program-specific resources is usually provided in the man page for the program. xterm's man page is a good example, as it contains a list of X resources and their default values.

To see the currently loaded resources: 

$ xrdb -query -all

Xresources syntax

Basic syntax

Tango-inaccurate.pngThe factual accuracy of this article or section is disputed.Tango-inaccurate.png

Reason: XScreenSaver 6.0 uses xscreensaver-auth.default.Dialog.headingFont which does not fit the "name.Class.resource" scheme described here. (Discuss in Talk:X resources)

The syntax of an Xresources file is as follows: 

name.Class.resource: value

and here is a real world example: 

xscreensaver.Dialog.headingFont: -*-fixed-bold-r-*-*-*-100-*-*-*-*-iso8859-1
name
The name of the application, such as xterm, xpdf, etc
class
The classification used to group resources together. Class names are typically uppercase.
resource
The name of the resource whose value is to be changed. Resources are typically lowercase with uppercase concatenation.
value
The actual value of the resource. This can be 1 of 3 types:
  • Integer (whole numbers)
  • Boolean (true/false, yes/no, on/off)
  • String (a string of characters) (for example a word (white), a color (#ffffff), or a path (/usr/bin/firefox))
delimiters
A dot (.) is used to signify each step down into the hierarchy — in the above example we start at name, then descend into Class, and finally into the resource itself. A colon (:) is used to separate the resource declaration from the actual value.
Note: For more information about Xresources file syntax see XrmGetDatabase(3) § FILE_SYNTAX.

Wildcard matching

Question mark (?) and asterisk (*) can be used as wildcards, making it easy to write a single rule that can be applied to many different applications or elements. ? is used to match any single component name, while * is used to represent any number of intervening components including none.

Using the previous example, if you want to apply the same font to all programs (not just XScreenSaver) that contain the class name Dialog which contains the resource name headingFont, you could write: 

?.Dialog.headingFont:     -*-fixed-bold-r-*-*-*-100-*-*-*-*-iso8859-1

If you want to apply this same rule to all programs that contain the resource headingFont, regardless of its class, you could write: 

*headingFont:    -*-fixed-bold-r-*-*-*-100-*-*-*-*-iso8859-1

For more information about wildcard matching rules see XrmGetResource(3) § MATCHING_RULES.

Comments

Lines starting with an exclamation mark (!) are ignored, for example: 

! The following rule will be ignored because it has been commented out
!Xft.antialias: true

Note that the exclamation mark must be the first character on the line.

Include files

Note: You need to have a C preprocessor, such as GNU CPP, installed to use this functionality.

To use different files for each application, use #include in the main file. For example: 

~/.Xresources
#include ".Xresources.d/xterm"
#include ".Xresources.d/rxvt-unicode"
#include ".Xresources.d/fonts"
#include ".Xresources.d/xscreensaver"

If files fail to load, specify the directory to xrdb with the -I parameter. For example: 

~/.xinitrc
xrdb -I$HOME ~/.Xresources

Getting resource values

If you want to get the value of a resource (for example if you want to use it in a bash script) you can use xgetresAUR: 

$ xgetres xscreensaver.Dialog.headingFont
-*-fixed-bold-r-*-*-*-100-*-*-*-*-iso8859-1

Sample usage

The following samples should provide a good understanding of how application settings can be modified using an Xresources file. See this gist for more examples. Refer to the man page of the application in question otherwise.

Troubleshooting

Parsing errors

Display managers such as GDM may use the --nocpp argument for xrdb.

No output from xrdb -query

It is not rare for xrdb -query to output nothing. Try following #Load resource file and #xinitrc from above. And note some of the files mentioned there could be empty.

See also