Assign privilege for a specific user into a directory/file

[root@ns1 /]#    getfacl ( to see )

[root@ns1 /]#    setfacl -m u:username:permission /directoryname ( to provide permission)
such as "setfacl -m u:momin:rwx /support "

[root@ns1 /]#    setfacl -x u:username /directoryname ( remove from permission )

[root@ns1 /]#    setfacl -x u:username /directoryname (remove from group permission)