Change primary display in Ubuntu 10.10

My desktop at my office doesn't use NVidia graphics card, but uses ATI Radeon. So I don't have the monitor setting application from NVidia I usually use for my laptop. So I searched a bit, and found a way to do it through command line.

The command to use is xrandr. It is the command line interface to the RandR X extension which is used to configure which display ports are enabled, and to configure display modes and properties such as orientation, reflection and DPI.

Usage:

# To query what screens are connected, type the following:
$ xrandr -q
# Using the name of the output from the query, you can set 
# a display output as the primary display:
$ xrandr --output CRT2 --primary

To make this run at the startup, go to System=>Preferences=>Startup Applications
Click Add
Name: XRANDR
Command: xrandr --output CRT2 --primary
Source: http://www.thinkwiki.org/wiki/Xorg_RandR_1.2