How to set the root password under Linux (first time)

[Email protected]:~$ su-root
Password:
Su:authentication failure

Please enter the root password when installing the user password instead of the root password Ununtu can only call root can not be directly rooted login
Here's how to set the root password:
1: input sudo passwd root
2: Enter user password (set at installation)
3: Enter the root password you want to set
4: Enter the root password again enter the end of the success

[Email protected]:~$ sudo passwd root
[sudo] password for Majingwei:
Enter New UNIX Password:
Retype new UNIX Password:
Passwd:password updated successfully
[Email protected]:~$

How to set the root password under Linux (first time)