Filesystem Organization

Mac OS X defines several folders across the filesystem as holding special significance to the system. Individual applications, as well as the system software itself, consult these directories when scanning for certain types of software or resources installed on the machine. For example, a program that wants a list of fonts available to the whole system can look in /Library/Fonts and /System/Library/Fonts. Font files can certainly exist elsewhere in the filesystem, but relevant applications aren’t likely to find them unless they’re in a predictable place.


You might also have a /Library/Fonts folder inside your home folder, and perhaps yet another inside /Network. Each of these Fonts folders exists inside a separate domain, Mac OS X’s term for the scope that a folder resides in (in terms of both function and permission from the current user’s point of view). The system defines four domains.


The term “domain” is a contender for the most overloaded word used to describe Mac OS X. While reading this section, try not to confuse the concept of filesystem domains with that of Internet domain names (such as “”) or NetInfo domains (as covered in Chapter 12). None of these have anything to do with each other.


Contains folders that are under complete control of the current user. Generally speaking, this includes the user’s Home folder and everything inside it.


Holds folders and files usable by all users of this machine, which may ...

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