--get your your Linux knowledge
> Linux Reviews > Howtos >

XFree configuration

How to configure and tune your XFree server

  1. The XFree config file
  2. ATI Based Graphics Cards
  3. Starting applications on another screen or computer
  4. Keyboard shortcuts

1. The XFree config file

XFree is configured by the textfile /etc/X11/XF86Config.

Some distributions (Redhat/Mandrake) use two config files, for those the system is:

/etc/X11/XF86Config Configuration for XFree 3.x
/etc/X11/XF86Config-4 Configuration for XFree 4.x

The default for XFree is /etc/X11/XF86Config.

2. ATI Based Graphics Cards

Gentoo ATI Radeon FAQ answers most questions about ATI based graphics cards and is also relevant for other distributions.

3. Starting applications on another screen or computer

If you have more than one display connected to your box and these are configured in XF86Config as seperate screens (not a shared desktop like xinerama or Nvidias TwinView does it) then your first display is named 0.0, your second 0.1, your thrid 0.2 and so on. The first number points to the number of the X-server you are using, unless you know you started a second one you only have one, named 0, running.

By using the variable DISPLAY= you can start applications directly on the screen of your prefernece.


DISPLAY=localhost:0.1 gqview

Most, but not all applications also supports choosing screen with the option --display=:

gqview --display=localhost:0.1

If you need to run a program like xmame through a frontend like gxmame and you want to start it on another display, you can make a script and use $* to pass all command line options on to the program in question. Example /usr/games/bin/

  xmame.xgl $*

X11 has great support for using remote displays on other boxes. This is done the same way, but first you most use xhost to tell the X-server where you wil be displaying the program that it is OK for the box where you are running the program to use that display.

Box A is a powerfull server and will be running our programs. It has IP

Box B is a Pentium 75 and will only display programs and read the keyboard and mouse. It has IP

Start X11 on Box B and run the command:


Now log into Box A using ssh, set the display to Box B and run your programs as usual:

  ssh you@
  gqview &

Note that Gentoo Linux users most run xhost localhost as the user who started (or logged into) the X11 server to allow other users (like root) run grapical programs.

4. Keyboard shortcuts

ctrl alt + smaller resolution
ctrl alt - bigger resolution
shift num-lock mouse-emulation of/off (arrow keys, + and - are mouse-buttons)
ctrl alt backspace Kills and closes the X server (emergency only)

Meet new people