GDM is the GNOME Display Manager, a graphical login program that uses the X Window System.
In addition to providing the equivalent of a console login prompt, GDM has the following advantages:
pre-loads the X Window System (though this can be a disadvantage for servers)
users can select various desktop environments and windows managers on a per-login basis
- assistance for users with disabilities
- per-login regional settings and keyboard layout
- consistent look and feel of other GTK/GNOME-themed applications
- all other functionality of XDM, including XDMCP support for managing remote displays
By default, the greeter is run as an unprivileged user and logging in as root is forbidden.
Controlling the GDM daemon
To temporarily stop the gdm service, you can run the following command as root:
#invoke-rc.d gdm3 stop
Other available options include: start, restart, reload and force-reload. For more information about general daemon management, see Daemon.
Customizing the GDM appearance
GDM v3.0+ allows for some basic customization, such as changing the logo icon, display background, and GTK theme. To do so:
Edit /etc/gdm3/greeter.gconf-defaults as root
- Uncomment and/or modify the desired settings
- Save and close the editor
Finally, run as root: dpkg-reconfigure gdm3
The command, 'dpkg-reconfigure gdm3' will cause gdm to reload its configuration upon the next logout or reboot.
Note: When changing the background image, the target file must be world-readable.