Error prompt: "XXX is not in the sudoers file" ---- Solution

// Situation
System prompts "XXX is not in the sudoers file" (xxx equals the user name) while executing command "sudo ":

1. Sudo-I
2. Password:
3. XXX is not in the sudoers file. This incident will be reported.

// Analysis
The current account must have no rights to execute "sudo ".

// Solution
To fix the problem, add the current account into the file "/etc/sudoers ":
1. Switch to Supervisor: su
2. open the file "sudoers" with VI Editor: VI/etc/sudoers

3. add the account: Press "I" to edit; find line "root all = (all) All"; new a line "XXX all = (all) All" below it; save & quit with the command "WQ! ".

Problem solved.