Su command under Ubuntu

The su command is used to switch between users, either from a common user to a root user or from a root user to a common user. When a common user switches to a root user, the authentication password is required. In ubuntu, when a user switches from a common user to a root user for the first time, the system will prompt that the su authentication fails. The solution is as follows:

◆ The su to root setting process is as follows:
Test @ test-desktop :~ $ Sudo passwd

Enter a new Unix Password:

Re-enter the new Unix Password:

Passwd: the password is successfully updated.

Test @ test-desktop :~ $ Su

Password:

Root @ test-desktop:/home/test #

To return to a common user from the root user, run the su *** command (or exit the root user and return to the common user)

Root @ test-desktop:/home/test # su Test

Test @ test-desktop :~ $