cats> fs la .
Access list for . is
Normal rights:
  system:administrators rlidwka
  system:anyuser rl
  avg rlidwka
  tsf rlidwka
cats> fs sa . tsf none       
cats> fs sa . system:anyuser none
cats> fs la .
Access list for . is
Normal rights:
  system:administrators rlidwka
  avg rlidwka

note that read and write can be used besides all and none with sa.