sed: sbase sed
Sad sidenote on m4, that even with strict POSIX [1], you still have no clue if `define` will turn into “” or “define” due to a split between AT&T on one hand and GNU and BSD (all of them?) on the other that POSIX did not rule one way or the other. It gets even worse when you realise that some m4 implementations have “constants” like `windows` so that “Stained glass windows” can turn into “Stained glass 0”. But I guess this can be expected when you are dealing with a tool that has evolved in multiple directions since 1977?
[1]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/m...
Some communities(iglunix, kisslinux, carbs linux, wyvertux, oasis linux, ...) are actively researching alternatives to the "standard" coreutils. You could check what they use, perhaps you'll find something interesting and strict. But general source is digging of course :)
> But I guess this can be expected when you are dealing with a tool that has evolved in multiple directions since 1977?
Exactly. 100% conformance isn't always possible, especially when standard is unclear on some things.
