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> I think part of the problem is that we still don't have a standard /bin/sh even though there is a written standard. It feels fair to me to suggest that you ca

> I think part of the problem is that we still don't have a standard /bin/sh even though there is a written standard. It feels fair to me to suggest that you can call dash the working standard on Linux, but you can't trust that beyond Linux systems(and I'm ignoring installs that are busybox-based here too). Why do we need a one true shell that implements the standard? Am I misunderstanding you…? The whole point of a standard is that everyone implements it so the different implementations don’t matter (and everyone does implement it, in the case of POSIX shell, minus a couple things like [ -t ] and some bash defaults).

JNRowe 4y ago
Given developers testing against shells that implement the spec, and a solid spec, and a variety of implementations that correctly implement that spec then I'm in full agreement with you. However, the moment you add caveats to that description you have, well… caveats to that description. The situation - as I see it - is that we have a spec, and we have systems that ship a /bin/sh that implements something like it. If people are targetting their system's /bin/sh, then they're writing scripts for their /bin/sh implementation not posix compliant shells. For example, my install uses dash which has features beyond the posix spec which I have to eschew to produce portable scripts. As a sibling comment points out shellcheck will point out a lot problems, but it requires people choosing to use it. You only have to dive around /usr/bin for a little while to see its usage isn't universal ;) Of course, if the differences in implementation don't affect your usecase then it simply doesn't matter.