By Xah Lee. Date: 2003-12-30. Last updated: 2014-01-02. This page is tips about Mac OS X's command line tools about Mac's resource fork. The info on this page is tested on Mac OS X 10.4.x and OS X 10.6.x. What is a resource fork? Resource fork is a feature of the Mac's file system HFS Plus, and older file systems used by Mac such as HFS and “Macintosh file system”. A file has 2 parts: (1) data for