2016-03-22 12:31:50 -0700, Paul Eggert: [...] > It might be helpful to have some other environment variable that > meant "try to be strict about supporting only behavior required by > POSIX", as one could use that to develop shell scripts that were > more portable. However, that would be a lot of work to implement, > and it's not clear it's worth the hassle to develop, maintain, and > document. Plus, POSIX does not always specify behavior, so > portability wouldn't be guaranteed by this.
But then in that environment, true --help would report an error: true: no argument allowed and exit with a non-zero exit status like when other non-POSIX extensions are not supported. It wouldn't make true more POSIX conformant but it would help people write POSIX scripts by telling them the feature they rely on (true ignoring arguments) is not standard. The OP's request was primarily about increasing portability with other true implementation where in "true --help", the "--help" argument is ignored. I agree POSIX true doesn't accept arguments, but before GNU "true" started accepting --help, --version, you could do portably (if not standardly): true "$args" to be ignored -- Stephane