Most file systems include attributes of files and directories that control the ability of users to read, change, navigate, and execute the contents of the file system. In some cases, menu options or functions may be made visible or hidden depending on a user's permission level; this kind of user interface is referred to as permission-driven.
Two types of permissions are widely available: POSIX file system permissions and access-control lists (ACLs) which are capable of more specific control.