OS X Library Directory Details

The Library directories are where the system and your code store all of their related data and resources. In OS X, this directory can contain many different subdirectories, most of which are created automatically by the system. In iOS, the app installer creates only a few subdirectories in ~/Library (such as Caches and Preferences) and your app is responsible for creating all others.

Table A-1 lists some of the common subdirectories you might find in a Library directory in OS X along with the types of files that belong there. You should always use these directories for their intended purposes. For information about the directories your app should be using the most, see “The Library Directory Stores App-Specific Files.”

Table A-1  Subdirectories of the Library directory

Subdirectory

Directory contents

Application Support

Contains all app-specific data and support files. These are the files that your app creates and manages on behalf of the user and can include files that contain user data.

By convention, all of these items should be put in a subdirectory whose name matches the bundle identifier of the app. For example, if your app is named MyApp and has the bundle identifier com.example.MyApp, you would put your app’s user-specific data files and resources in the ~/Library/Application Support/com.example.MyApp/ directory. Your app is responsible for creating this directory as needed.

Resources required by the app to run must be placed inside the app bundle itself.

Assistants

Contains programs that assist users in configuration or other tasks.

Audio

Contains audio plug-ins, loops, and device drivers.

Autosave Information

Contains app-specific autosave data.

Caches

Contains cached data that can be regenerated as needed. Apps should never rely on the existence of cache files. Cache files should be placed in a directory whose name matches the bundle identifier of the app.

By convention, apps should store cache files in a subdirectory whose name matches the bundle identifier of the app. For example, if your app is named MyApp and has the bundle identifier com.example.MyApp, you would put user-specific cache files in the ~/Library/Caches/com.example.MyApp/ directory.

ColorPickers

Contains resources for picking colors according to a certain model, such as the HLS (Hue Angle, Saturation, Lightness) picker or RGB picker.

ColorSync

Contains ColorSync profiles and scripts.

Components

Contains system bundles and extensions.

Containers

Contains the home directories for any sandboxed apps. (Available in the user domain only.)

Contextual Menu Items

Contains plug-ins for extending system-level contextual menus.

Cookies

Contains data files with web browser cookies.

Developer

Contains data used by Xcode and other developer tools.

Dictionaries

Contains language dictionaries for the spell checker.

Documentation

Contains documentation files and Apple Help packages intended for the users and administrators of the computer. (Apple Help packages are located in the Documentation/Help directory.) In the local domain, this directory contains the help packages shipped by Apple (excluding developer documentation).

Extensions

Contains device drivers and other kernel extensions.

Favorites

Contains aliases to frequently accessed folders, files, or websites. (Available in the user domain only.)

Fonts

Contains font files for both display and printing.

Frameworks

Contains frameworks and shared libraries. The Frameworks directory in the system domain is for Apple-provided frameworks only. Developers should install their custom frameworks in either the local or user domain.

Internet Plug-ins

Contains plug-ins, libraries, and filters for web-browser content.

Keyboards

Contains keyboard definitions.

LaunchAgents

Specifies the agent apps to launch and run for the current user.

LaunchDaemons

Specifies the daemons to launch and run as root on the system.

Logs

Contains log files for the console and specific system services. Users can also view these logs using the Console app.

Mail

Contains the user’s mailboxes. (Available in the user domain only.)

PreferencePanes

Contains plug-ins for the System Preferences app. Developers should install their custom preference panes in the local domain.

Preferences

Contains the user’s preferences. You should never create files in this directory yourself. To get or set preference values, you should always use the NSUserDefaults class or an equivalent system-provided interface.

Printers

In the system and local domains, this directory contains print drivers, PPD plug-ins, and libraries needed to configure printers. In the user domain, this directory contains the user’s available printer configurations.

QuickLook

Contains QuickLook plug-ins. If your app defines a QuickLook plug-in for viewing custom document types, install it in this directory (user or local domains only).

QuickTime

Contains QuickTime components and extensions.

Screen Savers

Contains screen saver definitions. See Screen Saver Framework Reference for a description of the interfaces used to create screen saver plug-ins.

Scripting Additions

Contains scripts and scripting resources that extend the capabilities of AppleScript.

Sounds

Contains system alert sounds.

StartupItems

(Deprecated) Contains system and third-party scripts and programs to be run at boot time. (See Daemons and Services Programming Guide for more information about starting up processes at boot time.)

Web Server

Contains web server content. This directory contains the CGI scripts and webpages to be served. (Available in the local domain only.)