dsc_extractor from Apple's open source dyld project
Open dyld.xcodeproj, select dsc_extractor target, selector Any Mac destination and archive.
Just clone and copy bin/dsc_extractor to your PATH and chmod with +x
dsc_extractor <path-to-cache-file> <path-to-device-dir>
See Apple's open source licence.
The external dependency in external folder can be downloaded from opensource.apple.com and developer.apple.com/security