Ubuntu - Sudo - Sudo Warning Message

Enable the default warning message whenever “sudo” is used.

Edit sudoers file by typing:

sudo EDITOR=vim visudo

Add the following line near the other defaults:

Defaults lecture=always

NOTE: Instead of always you can use once too.

To make sure the syntax of the edited file is not incorrect, check it with the following command and look for parsed: OK.

NOTE: If you mess up the syntax in this file, it can cause you problems using the “sudo” command.

visudo -c

To customize the message, you can create a custom message file.

Edit the lecture file by typing:

touch /etc/lecture
chmod 644 /etc/lecture
vi /etc/lecture

Add the following text (which is default) or whatever you want:

We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:

    #1) Respect the privacy of others.
    #2) Think before you type.
    #3) With great power comes great responsibility.

Now point to the newly-created file in the sudoers config file.

sudo EDITOR=vim visudo

Defaults lecture_file=/etc/lecture