How to change the LightDM theme/greeter?

I downloaded a couple greeters for LightDM, but I have not figured out how to enable them. Is there a way to switch greeter, either by graphical or command-line method?. I do not intend to change display manager, nor the background, but to change the layout and appearance of the login screen through a different "theme" (greeter is the name for LightDm themes). Thanks for your time.

Solution 1:

Just edit the greeter-session option in /etc/lightdm/lightdm.conf to the desired greeter.

If you for example want to use the lightdm-gtk-greeter.

Open up '/etc/lightdm/lightdm.conf' with any editor as root. For examplesudo vim /etc/lightdm/lightdm.conf then change the line

greeter-session=unity-greeter

to

greeter-session=lightdm-gtk-greeter

If the file does not exist, let it contain

[SeatDefaults]
greeter-session=lightdm-gtk-greeter

Then all you have to do is make sure that the greeter is installed (e.g. the package lightdm-gtk-greeter) and then restart lightdm.

Solution 2:

Change the LightDM Greeter

KDM, another display manager, has themes that may be changed using a configuration front end. LightDM has greeters that may be changed, but there is no front end.

LighDM configuration is governed by the lightdm.conf file, however it's not suppose to be directly edited, instead use the backend lightdm-set-defaults.

Before you change LighDM configuration, make a backup up the file:

sudo cp /etc/lightdm/lightdm.conf /etc/lightdm/lightdm.conf.old

There are several LightDM greeters, such as lightdm-unity-greeter, lightdm-gtk-greeter, lightdm-webkit-greeter, and lightdm-kde-greeter.

For this example I will use lightdm-kde-greeter.

If you are doing this from a root console, type all commands without sudo. For the following commands, if you are using a GUI (graphical user interface), use the key sequence ALT-F2 or the Super key (usually the Windows key) and type term to open a terminal of your choice. If KDE default terminal, just type konsole.

Follow these steps carefully.

1. Be sure you have LightDM and the greeter of your choice installed by typing the following command.

   sudo apt-get install -s lightdm-kde-greeter

2. If you receive the message, "Unable to locate package ...," check what you typed if it was correct, enter the following sequence of commands then go to step 4. Otherwise, go to step 3.

   sudo apt-add-repository ppa:agateau/lightdm-kde
sudo apt-get update
sudo apt-get install lightdm-kde-greeter

3. If you do not see 0 newly installed in the following sequence: "0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded, then enter the command again without -s which is the option to simulate an action in apt-get. Then go to step 4.

   sudo apt-get install lightdm-kde-greeter

4. For many users, the command lightdm-set-defaults will not be found because it is not in their path. For this reason, we will use /usr/lib/lightdm/lightdm-set-defaults. To set the greeter to lightdm-kde-greeter type the following command in a terminal:

   sudo /usr/lib/lightdm/lightdm-set-defaults --greeter lightdm-kde-greeter

5. If you are in a root console or have Xephyr installed, you may check your set up using the built in testing function. You may only log in as yourself. Do not use sudo!

   lightdm --test-mode

6. For best results, shut down and restart your system. Remember /etc/lightdm/lightdm.conf.old so you may use it to replace lightdm.conf if anything goes wrong. I suggest your write it down. If something goes wrong and you cannot log in, type this command that you also should have written down which writes your backup back to the configuration file.

   sudo cp /etc/lightdm/lightdm.conf.old /etc/lightdm/lightdm.conf

Note

I gleaned most of this information from the LightDM Ubuntu Wiki. Except for adding the PPA, the information is not release version specific and LightDM is beyond the testing stage. Read more at http://wiki.ubuntu.com/LightDM

If something goes horribly wrong.

1. If you have no graphics, go to a text terminal using CTRL-ALT-F1.
2. Stop LightDM with sudo stop lightdm.
3. Depending upon which you have installed, start GDM with sudo start gdm or KDM with sudo start kdm.
4. Run sudo dpkg-reconfigure lightdm to set the default display manager.
5. Edit /etc/X11/default-display-manager and set it to /usr/sbin/gdm or /usr/bin/kdm if you can't run the above.

6. Uninstall LightDM and GDM will replace it after a reboot.

   sudo apt-get remove lightdm