go get github.com/bodgit/megasd/...
To import an existing database generated by the C# tool:
megasd import /path/to/db.xml
(This will need the XML file and the original PNG image files.)
You can then scan your Micro SD card and generate the metadata:
megasd scan /Volumes/MEGADRIVE
The tool uses a small SQLite database, the location of which defaults to $PWD/megasd.db.
You can pass a --db flag or set the environment variable $MEGASD_DB to put this file somewhere else.