This script enables darktable to detect and import the in-camera star ratings on images shot with a Fujifilm camera.
From the directory containing fujifilm_ratings.lua, run the following:
$ mkdir -p ~/.config/darktable/lua/
$ ln -sf lib ~/.config/darktable/lua/lib
$ ln -sf fujifilm_ratings.lua ~/.config/darktable/lua/
$ echo 'require "fujifilm_ratings"' >> ~/.config/darktable/luarc
This script relies on the exiftool command-line utility. It should be
available in your distro's repository.
https://www.sno.phy.queensu.ca/~phil/exiftool/