Access Control List (ACL) allows computer users to get access to files and directories of the file system. In simple words, ACL consists of Specifying access permissions on associated files and directories. In Ex4 ACL comes enabled by the default but if not that you can enable it.

Before working on the access control list remember this filesystem must be mounted with the access control list enabled.

Enable Access Control List (ACL) in Linux

To enable the access control list on your Linux system you have to add this given below ACL option in your” /etc/fstab” 

UUID=54dd976c-b95d-4f44-b4f7-516107dbed85 / ext4 errors=remount-ro,acl ,0 1