1. Switch from user user to root
When we need to perform some operations with root privileges (such as repairing system files), we often need to use sudo authorization, which is very troublesome. At this point we can switch to the root user, just execute sudo su
Ubuntu's root user does not have a fixed password, its password is randomly generated and dynamically changed
Yes, it seems to change every 5 minutes, so using su (switch user) is not possible, because we don't know the root password
2. Switch back to user user from root user
If you want to switch back to the user user from the root user, just execute the command: su user (user is the user name when you installed it yourself), or directly enter exit, or Ctrl+D key combination to exit