XXX is not in sudoers file solution (convert)

Solution:
Switch to the root identity first
$ Su-
(Note that there is-, which is different from Su. When the "Su" command is used, the system only switches to root, but does not pass the root environment variable, or the current user's environment variable. Use the "Su-" command to bring the environment variable together, just like root login)

Then
$ Mongodo// Remember, there is no space between VI and sudo.

1. move the cursor to the last line
2. Press A to enter the append mode.
3. Input
Your_user_name all = (all) All
4. Press ESC
5. Enter ": WQ" to save the file)


In this way, you can add yourself to the sudo group and use the sudo command.