"Modern" sh (was Math routines)

[Guy Harris]

>It depends on when the last time you installed the system.  If it was
>1979 or such, then your shell probably doesn't understand # comments
>(I don't remember whether it was in the v7 shell, or not).

"#" comments weren't in the V7 shell.  They are the 4.2BSD shell, and
later BSD shells, and I think they were in the 4.1BSD shell as well;
Berkeley added "#" comments to their otherwise V7-based shell.