Here’s a guide on how to setup Linux to login automatically. This is meant for an embedded Linux environment more than a full-fledged desktop one, but it should work all the same. Before moving through this guide, ask yourself if you’d really like to login automatically or if you’d like to run a program automatically. Most folks want to login automatically so they can include a command line to be run in the ~/.bash_profile login scripts. This isn’t necessary. Instead, take a look at how to automatically run a program on system startup here:
http://www.thelinuxdaily.com/2010/01/automatically-start-a-script-at-linux-bootup/. If you’d still like to login automatically, then follow the steps below.
1.) The ﬁrst thing to be done is to install mingetty
apt-get install mingetty
2.) Edit the /etc/inittab ﬁle to include the line (you’ll need to find your console port for this one):
1:2345:respawn:/sbin/mingetty --autologin root ttyAM0:
There, your system will now automatically login as root.