http://www.unix.com – Hi, Here is the scenario: This file exists, with this ownership and group: Code: -rw-rw-r-- 1 picard starfleet 4 Jan 3 00:33 myfile.txt Output of the 'id' command for user picard is: Code: $ id picard uid=6392(picard) gid=723(human) groups=723(human),918(starfleet) Output of the 'id' command for user worf is: Code: $ id worf uid=7413(worf) gid=737(klingon) groups=737(klingon),918(starfleet) When worf runs: Code: (HowTos)