You may have noticed that I used the command visudo to edit the file /etc/sudoers, and you might ask yourself a very valid question: why not just edit the file /etc/sudoers directly without using visudo? Well, I will answer your question in a practical way.
First, run the visudo command and add the following line:
THISLINE=WRONG
Now try to save and exit:
root@ubuntu-linux:~# visudo
>>> /etc/sudoers: syntax error near line 14 <<<
What now?
Options are:
(e)dit sudoers file again
e(x)it without saving changes to sudoers file
(Q)uit and save changes to sudoers file (DANGER!)
What now?
As you can see, the visudo command detects an error, and it specifies the line number where the error has occurred.
Why is this important? Well, if you saved the file with an error in it, all the sudo rules in /etc/sudoers will not work! Let’s hit Q to save the changes and then try to list the sudo commands that can be run by user smurf:
What now? Q
root@ubuntu...