Usage on OSX?

[Saeven]

Hello! Thank you for the time you have put into this library.

I've downloaded/installed via brew, and have read the README, but try as I might nothing seems to work. I'm trying to set a limit on /Users/foo

quotatool -u foo -b -q 10G -l 12G /System/Volumes/Data/Users/foo

and

quotatool -u foo -b -q 10G -l 12G /Users/foo

both yield:

quotatool: Filesystem /Users/foo does not exist.

Similarly, invoking on any device listed in diskutil list yields the same error. Have I overlooked a detail?

Am on Big Sur, 11.3

Thanks for your guidance!