Set Ubuntu's root password

After installation, there is no password for the root user. Using the password set during the installation, one can still use "sudo" to carry out tasks with root priority. However, we cannot use "su" to change to the root user mode. To do so, we must first set the password for the root user.

Open the Terminal, type in "sudo passwd" and it will notify the user to type in th current user's password, then the new password for the root twice.

After that, type "su" and then password, we can work in the root user mode.