Every file has nine access modes associated with it.
The nine access modes are divisible into three sets of three switches. The protection fields of a UNIX file are displayed by using the command 'ls' followed by the '-l' option. The hyphen indicates that the permission is disabled. For example, if someone only has execute permission on a directory they can list or run a file in that directory but they can't get a listing of all the files in that directory. For that they would have to know the exact names in advance.