Linux supports POSIX ACLs, which I would classify as "default Unix" since it's POSIX, and also supports some extended non-portable ACLs: http://linux.die.net/m

Linux supports POSIX ACLs, which I would classify as "default Unix" since it's POSIX, and also supports some extended non-portable ACLs: http://linux.die.net/man/5/acl http://linux.die.net/man/5/acl http://www.vanemery.com/Linux/ACL/POSIX_ACL_on_Linux.html http://www.vanemery.com/Linux/ACL/POSIX_ACL_on_Linux.html