The security of most Unix-like operating systems has long been considered coarsely grained. One superuser, root, can do anything. Other users are lowly sharecroppers who endure the shackles root places upon them. The problem is that root doesn’t have many shackles and it can’t individualize the ones that it has very well. Some operating systems use POSIX access control lists (ACLs) to provide more fine-grained access controls, but these are difficult to configure correctly.^[15]

While it’s true that Unix-like operating systems don’t have detailed access controls, the fact is that most people don’t bother using the controls that do exist. Fortunately, you can combine groups and permissions to handle almost any problem securely.