[dalke]

I was thinking about this some more. You are right, but both you and I missed the point.

I think the author is saying that the problem is the "unix filesystem" is actually filesystem that doesn't match the unix, where 'unix' includes sh/csh/bash shell and command-line arguments which start with '-'.

If the filesystem wasn't a broad in what it accepted ... and the author is trying to convince us that POSIX allows that ... then it would a unix filesystem which was a better match to unix.