How to login as root in linux shell?
Reboot the computer. In the LILO boot loader, we should press Ctrl + X and type “linux single”. The sh-3.00# prompt should be displayed when Linux starts.
Type “passwd” and type the new password we want to use. Linux will ask us again to type the same password as confirmation.
Reboot the computer and start Linux normally. We should be able to login as root at the login screen. See How to Log In and Work as Root in Linux