alt Hacker News> C99 isn’t a compiler.
Sure, but the pojt here is that if we say "Write in X" we generally understand it to mean "Treat X like a standard and don't get too colloquial with the stylings."
Pedantry is worthwhile, but it can be a diminishing returns game.
Feels like you missed the point.
On the example of 'echo \n' - it's not defined in POSIX, therefore a script written in "POSIX shell" must simply never hit that case.
TFA kinda implies you can't target POSIX shell. That's silly, of course you can. The question is, what tools are there to check for compliance. Whether running on 14 shells is a good such tool - idk. Something specifically searching for POSIX violations might be better.