Ubuntu makes it easy to enable automatic login if you're using a login manager such as GDM. I was recently setting up a minimal Ubuntu 9.10 system with an LXDE desktop and no GDM. Here#8217;s how I enabled automatic login.
Note: This was tested on Ubuntu 9.10. Previous versions of Ubuntu require different procedures because of changes to the way Ubuntu boots.
Open /etc/init/tty1.conf as root:

sudo nano /etc/init/tty1.conf

Change the last line of this file to (where USERNAME is the username of the user you want to log in):

exec /bin/login -f USERNAME < /dev/tty1 > /dev/tty1 2>#038;1

Reboot, and the user you chose should be logged in automatically after boot. If something goes wrong, you can switch to a different TTY with CTRL+ALT+F2 and log in normally.
If you want this user to be logged into a graphical environment instead of just a shell, there#8217;s more work to be done. Open your user#8217;s .bashrc file:

nano ~/.bashrc

Add the following to the end of the file:

if [ $(tty) == "/dev/tty1" ]; then<br /> startx<br /> fi

This code will start X (the graphical environment) whenever the user logs in on TTY1. You can add more code after startx that will be executed if the user logs out of X.

[via tombuntu]