Application Bundle

Application Bundle

In NEXTSTEP, OPENSTEP, their lineal descendants OS X, iOS, and in GNUstep, a bundle is a directory that allows related resources such as an application's executable and its graphics to be grouped together, appearing as a single file to the user.

Examples include applications, frameworks, and plugins. They are accessed with the NSBundle class in Cocoa, NEXTSTEP and GNUstep's Foundation frameworks, and with CFBundle in Core Foundation.

A bundle usually contains one file representing executable code, and files that represent resources such as nibs, templates, images, sounds, and other media. On some other systems, such as Microsoft Windows, these resources are usually included directly in the executable file itself at compile time. On older Macintoshes, a similar technique is used, where additional metadata can be added to a file's resource fork. The Finder treats bundles, which can also be referred to as packages, as opaque files with no underlying structure.

The Uniform Type Identifier (UTI) for an Apple bundle is com.apple.bundle.

Similar in concept are the application directories used in RISC OS and on the ROX Desktop, and the RUNZ bundles in Super OS.