'read' Permission To A Selected Group Of Users, On A file

• Create a file with 'read' access to a selected Group of Users:
  • Ask the system administrator to create a new Group containing this list of Users.
    
    Note: We must be part of the Group, in order to be allowed to turn it into the Group-owner of the file.
  • Make the new Group be the Group-owner of the file:
    
    chgrp <group_name> <file_name>
  • Give 'read' access to "Group-owner":
    
    chmod g+r <file_name>
  • make sure "others" don't have 'read' access to this file:
    
    chmod o-r <file_name>
  • Give 'x' access to our home directory, so the Users will be able to reach for the file under it:
    
    chmod a+x ~
  • Note: if the file is in a sub-directory under our home directory, we must give 'x' access to all the directories along the way to this file.

Originally written by guy keren