I don’t know that switch! But it read from dockerfile? My strategy is a bit longer but it can guarantee that all is updated and I can also add git pull for every module in the sequence…
Edit: I give a try, but not works, and didn’t find that on documentation.
https://docs.docker.com/engine/reference/commandline/run/
@technofab what do you want to know? look at the section
https://forum.magicmirror.builders/category/12/show-your-mirror
where others have shown their assemblies and parts