The Access Control List (ACL) provides an extended set of permissions on files and directories, there are 2 commands available to use: setfacl, getfacl.
Consult man page for complete manual.
Sample use:
getfacl -c Video/
Gives out:
user::rwx group::r-x other::r-x
When it’s needed to share to others:
setfacl -m u:user2:5 getfacl -c Video/
Will return:
user::rwx user:user2:r-x group::r-x mask::r-x other::r-x
So user2 can only be read-only on this directory.
Removing all extended ACL and leave the default system rwx, use this command:
setfacl -b Video/