ACL ( Access Control Lists )

The Access Control List helps to assign permissions for files and directories for a particular user or group. For example, different permissions cannot be configured for different users and groups normally. Thus, Access Control Lists (ACLs) are used in those cases.
Note :-
The acl package is required to implement ACLs. It contains the utilities used to add, modify and remove ACL information.
Syntax :-
To Set acl for a file:-
# setfacl -m rules file
User:
Eg : # setfacl -m u:user1:rw /root

Group:
Eg : # setfacl -m g:group1:rwx /root
To check the acl permissions of a file:-
# getfacl file
Removing an ACL :-
# setfacl -x rules file
Eg:
# setfacl -x u:user1 /root