Run-anywhere scripting masochism of the day: I'm probably about to install an actual Unix SVR4 VM to find out just how well (or likely badly) my "works in modern posix tools" awk, m4, make, & sh scripts run in a real legacy Unix.
Answer: Not at all, at least not from the WinWorld archive. It turns out 'ed' is an optional package, and neither 'm4' nor 'make' are in the floppy set at all. I need either a SVR4 version other than AT&T 2.1 or a later Unix.
Wait, *Dell* had a Unix??? https://winworldpc.com/product/dell-unix/40
So Dell's SVR4 apparently had XPG3-conformant m4, awk, make, and sh included.
The answer is no, but only so far. My m4 script is descending so far into recursive expansions that I'm smashing its quoted string limit.
If I refactor a bit, I can probably make it run in SVR4 m4, Heirloom Project m4, FreeBSD m4 (my main target), and gm4, while remaining POSIX conformant.
So I had x11/bitmap, `magick file.xbm +level-colors "[foreground]","[background]" -strip file.png` in my notes, and a stupid thought clawing its way out. To be fair, it's false yet almost true again in the worst way: Just substitute Canonical for AT&T.