Access control list

We generally work with a basic set of access control with the help of chmod, chown, and chgrp commands that are available in Linux. Although they are useful, they do not provide granular control with respect to individual users.

Use case

There is a file named file.txt and the permissions associated with the file are as follows:

-rw-rw---- 1 kplabs kplabs 0 Jun 23 23:15 file.txt

There is a requirement where we need to give the users, Bob and Andy, read access to file.txt and James should have the rwx access to the file, and no one else apart from the owner and the three users should have any access to the file.

The permission requirement is explained via the following diagram:

How to implement this use case?

Let's think; is it possible via chmod?

The answer is, not really; this is the limitation that starts to reflect when we need more granular controls.

Introduction to Access Control List

Access Control List (ACL) provides additional controls to what is designed to work along with...