Set auto login Pi

To set auto login pi, without asking of user and password:

$ sudo nano /etc/inittab

comment the line(may be have little bit differency on various version):
#1:2345:respawn:/sbin/getty --noclear 38400 tty1

add the line:
1:2345:respawn:/bin/login -f pi tty1 </dev/tty1 >/dev/tty1 2>&1

/etc/inittab