Disable display manager on boot
From Rsewiki
On robots that is normally without a screen, there is no need to run a display manager and a graphic user interface.
This will save some memory and start less processes.
inspect /etc/init, there is a configuration entry for the installed display manager, e.g.
gdm.conf or kdm.conf
To start the display manager and graphic user interface when needed only, make a manual override file for the display manager:
sudo bash echo "manual" > /etc/init/gdm.override echo "manual" > /etc/init/kdm.override exit
After reboot, there will be a text login only. To (re)start the display manager (graphic login screen) use the command
sudo gdm or sudo kdm