Login or display manager is an interface for users to log in to their Linux system. Different Linux distributions choose other login managers for the system, and you can install and configure display managers on your own.
The default display/login manager for Ubuntu/GNOME is GDM. Kubuntu, however, uses SDDM as the default display/login manager.
If you have multiple display managers installed on your system, you can change the one used to log in to your system.
$ systemctl status display-manager ● gdm.service - GNOME Display Manager Loaded: loaded (/lib/systemd/system/gdm.service; static; vendor preset: enabled) Active: active (running) since Sat 2020-08-15 07:49:29 +08; 1 day 13h ago Process: 11141 ExecReload=/usr/share/gdm/generate-config (code=exited, status=0/SUCCESS) Process: 11143 ExecReload=/bin/kill -SIGHUP $MAINPID (code=exited, status=0/SUCCESS) Main PID: 919 (gdm3) Tasks: 3 (limit: 4624) Memory: 7.5M CGroup: /system.slice/gdm.service └─919 /usr/sbin/gdm3 Ogos 15 07:49:29 host gdm-launch-environment][935]: pam_unix(gdm-launch-environment:session): session opened for user gdm by (uid=0) Ogos 15 07:49:45 host gdm-password][1453]: pam_unix(gdm-password:auth): Couldn't open /etc/securetty: No such file or directory Ogos 15 07:49:46 host gdm-password][1453]: pam_unix(gdm-password:auth): Couldn't open /etc/securetty: No such file or directory Ogos 15 07:49:46 host gdm-password][1453]: gkr-pam: unable to locate daemon control file Ogos 15 07:49:46 host gdm-password][1453]: gkr-pam: stashed password to try later in open session Ogos 15 07:49:46 host gdm-password][1453]: pam_unix(gdm-password:session): session opened for user user by (uid=0) Ogos 15 07:49:47 host gdm-password][1453]: gkr-pam: gnome-keyring-daemon started properly and unlocked keyring Ogos 15 07:49:55 host gdm3[919]: Child process -998 was already dead. Ogos 16 21:37:24 host systemd[1]: Reloading GNOME Display Manager. Ogos 16 21:37:24 host systemd[1]: Reloaded GNOME Display Manager.
$ sudo dpkg-reconfigure gdm3 [sudo] password for user:
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