To auto login to linux console on boot, edit /etc/init/tty.conf

vi /etc/init/tty.conf

Find

exec /sbin/mingetty $TTY

Replace with

exec /sbin/mingetty --autologin root $TTY

diff with original tty.conf

[root@localhost ~]# diff /etc/init/tty.conf ~/tty.conf.original
9c9
< exec /sbin/mingetty --autologin root $TTY
---
> exec /sbin/mingetty $TTY
[root@localhost ~]#