The command sudo service gdm stop would successfully disable the X server in Ubuntu 11.04 temporarily.
However, this same command no longer works in Ubuntu 11.10, because "gdm" is an "unrecognized service" according to Terminal. How, then, do I disable the X server in Ubuntu 11.10?
GDM was switched out for LightDM, so:
sudo stop lightdm
Or in your service parlance:
sudo service lightdm stop
For future reference, all these upstart services (that can be run with initctl's service command and shortcuts) are .conf files in /etc/init/
The reason that doesn't work is because Ubuntu 11.10 has switched from GDM to LightDM.
Try this command instead:
sudo service lightdm stop
You can also use the keyboard shortcut:
Alt + PrtScn/SysReq + K
A bit of a long winded keyboard shortcut, maybe too many people were pressing Ctrl+Alt+Backspace so they changed it to this.
I can confirm this as working from 10.04 through to 11.10.
@Oli pretty much nailed it, but I wanted to note that this probably won't help you out much if you need to do something from the command line without X.
For that, you should press Ctrl+Alt+F1, then log in from the console. Afterwards, you can kill and restart the lightdm service as needed.
Technically speaking gdm or lightdm are managing desktop session requests they are not X servers. (an X server is serving events to X application, xorg is an X server :) .
To stop the X server killall Xorg or sudo killall Xorg if you are not owner of the process.
Of course you must have a terminal to do that.
One way if you cannot open a gnome terminal or an xterm is to start a text console; press simultaneously Ctrl + Alt + F1 keys, then login at the prompt (your password will not be shown, not even as asterisks). (F1 to F5 are ok)
old post but current question. The command sudo service mdm stop would successfully disable the X server in Linux Mint 17.3 temporarily. After install drivers you can do sudo service mdm start.
since this is the primary result that came up with the google search Solus stop X server, I wanted to add this answer because Solus doesn't use service.
for this, you can use sudo systemctl stop lightdm and do whatever you need to do.
