Turning off one monitor in a dual monitor setup (Linux, Nvidia)

If you, like me, have two monitors and sometimes want to turn one of them off (to watch a movie, as an example) but thinks that going to the nvidia-settings every time is a waste of time here is a solution!!

First you have to configure your dual monitor setup properly with the nvidia drivers. (You can do this with the nvidia-settings)

Now...

• Open the nvidia-settings and configure your monitors, putting one of them as disabled. (Here I have to go to the "X Server Display Configuration" and after selecting one monitor in "configuration" choose "Disabled")
• Press the "Save to X Configuration File" (Don't worry, we will not do anything)
• Press the "Show preview..." button
• In the new windows, at the section "screen" (in my file it is the last section) copy what appears after the 'Option "metamodes"'
• Cancel and close nvidia-settings

Now to the file edition part...

• Assure first that you have the package "x11-xserver-utils" installed (we will use the xrandr command)
• Open as super-user the file "/etc/X11/xorg.conf"
• At the "screen" section add one more option in the "metamodes":
• At the end of the string (before the quotes) add a semicolon
• Paste what you have copied from the nvidia-settings preview

To clarify...In my xorg.conf:

The metamodes, in my machine, before the modifications was:

Option "metamodes" "CRT: nvidia-auto-select +1920+56, DFP: nvidia-auto-select     +0+0"

Then, after the modification:

Option "metamodes" "CRT: nvidia-auto-select +1920+56, DFP: nvidia-auto-select +0+0;CRT: null, DFP: nvidia-auto-select +0+0"

After that you can create a bash script to turn on and off the monitor you chose.
To turn the monitor off:

#!/bin/bash
xrandr -s 1

To turn the monitor on:

#!/bin/bash
xrandr -s 0

The scripts (and the single commands, of course) will only work after you restart your X, usually by restarting your machine.

You can play with your monitor configuration, xrandr and xorg.conf (with due care) to turn off the other monitor or to fit it in your n-headed computer need :)

That's all folks!

I used the great help of this site:
http://morgancollett.wordpress.com/2008/11/25/nvidia-twinview-and-xrandr/