> The posix shell spec is missing a lot of reality. It’s not very actively maintained, unfortunately POSIX was primarily intended a descriptive specification,

> The posix shell spec is missing a lot of reality. It’s not very actively maintained, unfortunately POSIX was primarily intended a descriptive specification, rather than a prescriptive. That is, it attempted to document and standardize the common behaviour found on many platforms during the Great Unix Wars, rather than say "hey we thought of this great new thing and released a spec, go implement it!", which is more how, say, web standards work. I does/did have some of that, but it was never the main goal. These days "whatever Linux does" is the de-facto standard, for better or worse, and the need for POSIX is much less.