iDSK is a port of ManageDSK to Linux, Mac OS X and other UNIX OS made by Sid. This port is command-line only but features all the important functionality needed to manage DSK files:
- Create a empty .DSK file (in DATA format),
- Add some files in an existing .DSK file,
- Extract some files from an existing .DSK file,
- Rename some files contained in a .DSK file,
- Delete some files contained in a .DSK file,
You can download its source at Sid's homepage. (If you run Arch Linux, here is an AUR package.)
This tool works on all unix platforms, unlike cpcfs/cpcxfs which suffers from many endianness problems and can't work on powerPC, for example. The command line interface is designed for easy integration in a makefile, making it more efficient for cross-development.
You will probably want to use dsktools to write the dsk image to a real floppy.