lyzh@ubuntu:~$ passwd root passwd: You may not view or modify password information for root. lyzh@ubuntu:~$ sudo passwd root Enter new UNIX password: Retype new UNIX password: passwd: password updated successfully lyzh@ubuntu:~$ lyzh@ubuntu:~$ lyzh@ubuntu:~$ su root Password: root@ubuntu:/home/lyzh# root@ubuntu:/home/lyzh# root@ubuntu:/home/lyzh#
