In all versions of macOS and OS X I have access to from Mountain Lion to Big Sur, I can access the resource fork of any file or directory using the current syntax in the terminal:


I know that at some point this syntax replaced the previous syntax which was:


But I don't know when the change happened. I assume it was when the little known Named Forks feature was introduced. Apparently you could access any named fork in this era thus:


These days the latter two syntaxes do not work. No fork other than the resource fork is accessible, though the method to access it is the one that was originally due to named forks.

Named forks were introduced with HFS+ in 1988 with version 8.1 of the OS. Named forks were deprecated in 2013 with version 10.9, Mavericks.

The odd thing is that on my Mountain Lion machine, which was before named forks were deprecated, I can't access named forks, only the resource fork. Attempting to use the file/..namedfork/forkname where forkname is anything other than rsrc results in the Not a directory error.

This means that this method for accessing named forks went away before named forks were officially deprecated.

Does anybody know the history of when file/rsrc was introduced, when it was replaced with file/..namedfork/rsrc, and when file/..namedfork/anyotherforkname stopped working?


1 Answer 1


According to Wikipedia:

From the POSIX interface, the resource fork could be accessed as filename/..namedfork/rsrc or as filename/rsrc; the shorter form was deprecated in Mac OS X v10.4 and removed completely in Mac OS X v10.7.

It cites an archived Apple developer document.

10.7 is Lion, of course.

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