Access control lists provide a straightforward method of managing file and folder permissions. They are used by most operating systems, including Windows, Mac, and Unix systems. While ACLs are typically hidden from the user, they can often be modified using a graphical interface. For example, in Mac OS X 10.5, ACL settings can be edited by selecting a file or folder and choosing "Get Info." The access control settings can be modified within the "Sharing and Permissions" section of the window. On Unix systems, ACLs can be edited using the chmod() command.