Disable GUI in Ubuntu 18.04. desktop? (SSH/Webmin headless setup)

Solution 1:

For Ubuntu 18.04, the following will work without additional modifications.

systemctl set-default multi-user.target

How to disable GDM from being automatically started?

Solution 2:

Yes, your desktop is started from a systemd webservice. Disable it and you can still manually start it. systemctl list-units --type service --all will list all services. For me it lists "gdm.service".

This should show the status of your session:

systemctl status gdm.service

This disables it:

systemctl disable gdm.service

And this enables it again:

systemctl enable gdm.service

Replace it with kde if you use kUbutu. Or by any of the other desktop you use.

You might need to kill the current active desktop too.

If you intend to use this system as a server you can also delete the desktop itself with sudo apt purge ubuntu-desktop. Be careful: do this while you have a ssh connection so you can still issue commands; locking yourself out of the system might be fatal.