ffs, the file filesystem, let's you mount semi-structured data as a filesystem---a tree structure you already know how to work with!

Working with semi-structured data using command-line tools is hard. Tools like jq help a lot, but learning a new language for simple manipulations is a big ask. By mapping hard-to-parse trees into a filesystem, you can keep using the tools you know.

Run ffs [file.blah] to mount file.blah at the mountpoint file. The final, updated version of the file will be outputted on stdout.

$ cat object.json 
{ "name": "Michael Greenberg", "eyes": 2, "fingernails": 10, "human": true }
$ ffs -o object_edited.json object.json &
[1] 60182
$ tree object
object
├── eyes
├── fingernails
├── human
└── name

0 directories, 4 files
$ echo Mikey Indiana >object/name
$ echo 1 >object/nose
$ mkdir object/pockets
$ cd object/pockets/
$ echo keys >pants
$ echo pen >shirt
$ cd ..
$ cd ..
$ umount object
$ 
[1]+  Done                    ffs -o object_edited.json object.json
$ cat object_edited.json 
{"eyes":2,"fingernails":10,"human":true,"name":"Mikey Indiana","nose":1,"pockets":{"pants":"keys","shirt":"pen"}}

You can specify an explicit mountpoint by running ffs -m MOUNT file; you can specify an output file with -o OUTPUT. You can edit a file in place by running ffs -i file---when the volume is unmounted, the resulting output will be written back to file.

You need an appropriate FUSE or macFUSE along with pkg-config.

See the GitHub build workflow for examples of external dependency installation.