How to set up automatic login in Linux with LightDM

First, make sure you are using the LightDM display manager:

systemctl status display-manager

Line

lightdm.service - Light Display Manager

confirms that this OS uses LightDM.

Logging into Linux with LightDM (style and background images may vary on other Linux distributions):

To automatically login to LightDM, open the configuration text file /etc/lightdm/lightdm.conf:

sudo gedit /etc/lightdm/lightdm.conf

Find the [Seat:*] section there (or it may be called [SeatDefaults]), and in this section there are two commented lines:

#autologin-user=
#autologin-user-timeout=0

Uncomment them (remove the # symbol at the beginning of the line), and after autologin-user enter the username for which automatic login should be performed, for example, if this is the root user, then the lines look like this:

autologin-user=root
autologin-user-timeout=0

If you do not know or have forgotten the username of the Linux system, then you can find it out by running the command in the terminal:

whoami

If the lightdm.conf file does not exist at all, then create it:

sudo gedit /etc/lightdm/lightdm.conf

Copy to this file:

[Seat:*]
autologin-guest=false
autologin-user=mial
autologin-user-timeout=0

Note the autologin-user directive and the username that follows it, “mial”. You, of course, need to replace this name with your own system username.

Now open the /etc/pam.d/lightdm-autologin file:

sudo gedit /etc/pam.d/lightdm-autologin

Find the line there:

    auth      required pam_succeed_if.so user != root quiet_success

and replace it with:

    auth      required pam_succeed_if.so user != anything quiet_success

Reboot – after that, you should be automatically logged in without entering a password.

If it does not work, to check if the settings from the lightdm.conf configuration file are applied, run the command:

/usr/sbin/lightdm --show-config