On Tue, Mar 9, 2021 at 2:50 PM Michael Orlitzky <michael@xxxxxxxxxxxx> wrote: > > the $(...) syntax was standardized no later than 1997 It was first formally standardized as part of the POSIX shell in 1989, which standardized what used to be called ksh88 <https://web.archive.org/web/20151105130220/http://www2.research.att.com/sw/download/man/man1/ksh88.html> . Since all versions of Solaris postdate this, Sun really should have made /bin/sh a POSIX shell from the start, but for whatever reason, did not, and now that decision's causing us problems. I doubt the feature was added to ksh in 1988, since Kornshell has roots going back to 1982, even though it wasn't formally made part of Unix® until SVR4 in 1988. If you're seeing all this 1988 and 1989 stuff and wondering if there's a coincidence, no, there isn't. POSIX was originally a formalization of SVR4 Unix, meant to heal the rift with BSD. How well that worked is a matter of history. The point is, what we now call the standard Unix shell dates to this time. In an ideal world, we'd have been able to depend on $() flavor command substitution since 1989-1992, depending on where you date the beginning of POSIX-certified Unixes.
