I'm using lockscreen that came with Ubuntu Gnome. It's called GDM. can I replace it with LightDM or lockscreen that comes with KDE , LXDE or others?
what are the names of these packages? how to install them?
If that's too broad then
- How can I just install LightDM without affecting my Ubuntu Gnome Installation?
- How can I uninstall it and get GDM back if I don't like the experience?
To install an alternate login manager use software manager or the command line
You can try slim or lightdm, both probably lighter then kdm, or try them all.
To remove them
or slim or lightdm
To select which one to use use sudo dpkg-reconfigure gdm or edit
/etc/sysconfig/displaymanager
you will get a screen where you can select which display manager (login screen) to use.
Use you up/down arrow keys to select and hit enter key.
or
and change to the dm you wish, such as
sudo dpkg-reconfigure gdm
has the advantage of less typing and less typographical errors.Locking the screen when you are inactive is a different issue and is a property of the screensaver you use. By default it is gnome-screensaver but xscreensaver is probably the most popular alternate.
To configure and change screensaevers see Configure screensaver in Ubuntu