Resource Fork - Editing Resource Forks

Editing Resource Forks

As the resource fork can be edited with a resource editor such as ResEdit, it can be used to localize and customize software. In addition, most resource editors allow visual editing of data. In OS X, it is possible to use resources when developing an application. However, if the application may need to be used in UFS, it is also possible to configure it so that the entire resource fork is moved to the data fork, using the Raw Resource File setting. The integrated development environments distributed for free by Apple Inc., which include MPW and Apple Developer's Tools, include a compiler called Rez. This uses a dedicated language, also called Rez, which can be used to create a resource fork by compiling source code. A decompiler, DeRez, which can be used to change a resource fork back into Rez code is also included.

In the structure of the resource fork, there is a piece of data called a “resource map” which stores the positions of resource data items. This can be used to allow random access to resource data based on the defined IDs and names. The resource fork can be thought of as consisting of essentially two objects, the resource map and the resource data itself, but in fact each data type is a hierarchical structure which stores multiple items of data. The format in which the information in the resource data is stored is defined based on the types of information, which are known as “resource types.” Resource data often makes references to other types of data.

To view the resource fork in the Terminal application. Append “/..namedfork/rsrc” to your command. e.g., take the command “ls -aol IMG_0593.jpg” then append the resource fork viewing suffix “ls -aol IMG_0593.jpg/..namedfork/rsrc” to view the ls -aol command information of the resource fork of file “IMG_0593.jpg”