Ubuntu Linux system su: Appearance: Authentication failure Solution

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Under the newly installed Ubuntu system, I am 14.0.4 do not know whether other systems will be the same problem. When you enter the SU command to get root permissions, there is a
The problem with authentication failure is that authentication fails.
The following actions are required:

sudo passwd rootEnter new UNIX password:                                     //此时输入你的密码Retype new UNIX password:                                  //再次输入，相同密码passwd: password updated successfully

With the SU command at this point, you can get root permission.

Ubuntu Linux system su: Appearance: Authentication failure Solution