csh pleasures

[Guy Harris]

>Older versions of C-shell had && and || exchanged - to the extra fun of
>novices!

And that loser version (as I remember, the bug was basically that the
author forgot that an exit status of 0 means "true" and a non-zero exit
status means "false") made it into Xenix, from what I've heard, which
prolonged its life far beyond what it should have been - that version
ended up being the C shell shipped with S5R3.2.

S5R4 has a C shell based on the SunOS 4.1 one, which is in turn based on
the 4.3BSD one, so that bug is fixed.