user@ubuntu:~$ sudo adduser guest
user@ubuntu:~$ sudo passwd -d guest

guest:U6aMy0wojraho:15048:0:99999:7:::

guest:U6aMy0wojraho:15048:0:99999:7:::

#!/bin/bash

# Launches the guest session
/usr/share/gdm/guest-session/guest-session-launch
# Logs the user when done
/usr/bin/gnome-session-save --logout