Display a message while prompting for sudo password

Question

I had once seen a Ubuntu user use a sudo command in a terminal. Before he was prompted for a password he was shown the following message:

user1@linuxbox:~$ sudo apt-get update
Please do not run this command if you have not been granted sudo rights.
[sudo] password for user1:

I would like to display a similar message on my system when a user runs a sudo command. What must I edit/change to display a similar message when a user runs a sudo command on the terminal?

Solution 1

See if your sudo supports lecture_file option

man sudoers | grep lecture_file

This is what man sudoers says in my case :

lecture_file Path to a file containing an alternate sudo lecture that will be used in place of the standard lecture if the named file exists. By default, sudo uses a built-in lecture.

So, to change the text, add it to a file e.g /etc/sudoers.lecture and point to it from /etc/sudoers :

Defaults        lecture_file = /etc/sudoers.lecture

To display the lecture on every invocation of sudo also add the following to /etc/sudoers:

Defaults        lecture = always

Solution 2

Write a "wrapper script" around the sudo command.

Basically, you replace the standard sudo command with a script that contains a function called sudo(). This function first echoes your custom message, then calls the standard sudo command /usr/bin/sudo.

This script would be something like:

#!/bin/bash
sudo(){
        echo "This is a custom message."
        /usr/bin/sudo "$@"
}

You need to make sure the script is in the path of the user. Here (under "Putting it all together") is a good explanation of how to do this. Google "wrapper script" for other examples.

Comments

[sudo]

Love how it's called "lecture." macOS gives you a lecture about abusing power when you first use sudo.

[Nonny Moose]

@sudo So does Ubuntu, at least in some situations.

[lotfio]

@storm and how to turn it off iam using debian stretch and the sudo message is displayed by default i tryed using something like lecture = off but it's not recognized

[storm]

@ABDELLATIFLAKEHAL : lecture = never