$ mkdir d $ cd d $ whoami > root $ id -Gn daemon > daemon bin $ mkdir n1 $ touch n1/f $ mkdir d2 d3 d4 d5 d6 d7 $ touch d2/f d3/f d4/f d5/f d6/f d7/f d7/g $ chown daemon d2 $ chgrp bin d3 $ chmod g+w d3 $ nfs4acl --set 'daemon:wx::allow' d4 $ nfs4acl --set 'daemon:d::allow' d5 $ nfs4acl --set 'daemon:xd::allow' d6 $ nfs4acl --set 'daemon:D::allow' d7/f d7/g $ chmod 664 d7/g $ mkdir s2 s3 s4 s5 s6 s7 $ chmod +t s2 s3 s4 s5 s6 s7 $ touch s2/f s3/f s4/f s5/f s6/f s7/f s7/g $ chown daemon s2 $ chgrp bin s3 $ chmod g+w s3 $ nfs4acl --set 'daemon:wx::allow' s4 $ nfs4acl --set 'daemon:d::allow' s5 $ nfs4acl --set 'daemon:xd::allow' s6 $ nfs4acl --set 'daemon:D::allow' s7/f $ nfs4acl --set 'daemon:D::allow' s7/g s7/g $ chmod 664 s7/g $ su daemon Cannot delete files without permissions: $ rm n1/f > rm: cannot remove `n1/f': Permission denied Can delete files we own: $ rm d2/f s2/f Cannot delete files where we are in the owning group in a non-sticky directory, but not in a sticky one: $ rm d3/f s3/f > rm: cannot remove `s3/f': Operation not permitted "Write_data/execute" access does not include delete_child access, and so this is not enough for deleting: $ rm d4/f s4/f > rm: cannot remove `d4/f': Permission denied > rm: cannot remove `s4/f': Permission denied "Delete_child" access alone also is not sufficient: $ rm d5/f s5/f > rm: cannot remove `d5/f': Permission denied > rm: cannot remove `s5/f': Permission denied "Execute/delete_child" on the directory does allow that, though, but only in a non-sticky directory: $ rm d6/f s6/f > rm: cannot remove `s6/f': Operation not permitted "Delete" on the child itself overrides the sticky check as well: $ rm d7/f s7/f But Delete is not a subset of POSIX read/write, so chmod turns it off: $ rm d7/g s7/g > rm: cannot remove `d7/g': Permission denied > rm: cannot remove `s7/g': Permission denied $ su $ cd .. $ rm -rf d