Xorg doesn't need a configuration file as it now is perfectly able to guess the hardware it runs on. If you want to store a configuration file, just make sure directory
/etc/X11/xorg.conf.d exists. It most likely doesn't, which is normal, then just create it. It should be made writeable to root only and readable to everyone (i.e. mode
755). Store your configuration file there – you will have to save it from your current session and copy the file with root or
Optionally you might want to keep only the relevant sections, i.e.
Monitor. If you're happy with how Xorg detects your input devices, you may safely omit the
Serverlayout along with the
I think the nvidia driver is smart enough to not leave Xorg headless in case something goes wrong – it just never happened to me hence my assumption. Otherwise you just need to
rm your file from the system configuration directory.
After your configuration file is changed all you need to do is restart Xorg by logging off and then on again. Most of the time it's enough. Otherwise reboot your machine.
Note: I could have described how to restart Xorg but there are too many variations to take into account. Most of the time logging off and on will do.