Since the Ubuntu Server edition doesn’t by default install a window manager, you may want to install one yourself (if you need one). This is how to do so.

Either use the tasksel command, or just directly type in (only one) of the following commands:

sudo apt-get install ubuntu-desktop
sudo apt-get install lubuntu-desktop
sudo apt-get install xubuntu-desktop
sudo apt-get install kubuntu-desktop
sudo apt-get install edubuntu-desktop

If you want to install a very minimal GUI environment, the use the following switch:

sudo aptitude install --no-install-recommends ubuntu-desktop

If you don’t want the GUI to start up at boot time, then open up /etc/init/lightdm.conf, and comment out the following lines (using ‘#’):

start on ((filesystem
           and runlevel [!06]
           and started dbus
           and (drm-device-added card0 PRIMARY_DEVICE_FOR_DISPLAY=1
                or stopped udev-fallback-graphics))
          or runlevel PREVLEVEL=S)

To start the GUI from console mode, use this command:

sudo start lightdm

Sources:

• http://askubuntu.com/questions/74645/possible-to-install-ubuntu-desktop-and-then-boot-to-no-gui
• http://askubuntu.com/questions/70188/how-do-i-boot-into-console-mode