Hi Jan, I really like the idea out json output for fs/block tools. nvme-cli has been doing it for a while, and that has been very useful. It comes with it's own little handrolled json output helpers: https://github.com/linux-nvme/nvme-cli/blob/master/json.c so it doesn't introduce any new dependencies. If you want to parse input as well a library might be a better approach, though. I really don't like the shared object evms model mention in the thread, as that creates hard ELF dependencies.