Rubenerd

This is how you disable the GUI after logging in and launching a shell:

sudo systemctl set-default multi-user.target
sudo systemctl reboot

I inadvertently installed a graphical environment installing a new Debian Xen test server. This will let you reboot to a tty.

For fellow BSD people, remember that the systemctl(8) command has also kudzu’d shutdown(8) on most Linux distros now. I wonder how long it’ll take for sudoedit(8) to be replaced with systemctl text-editor-edit.