Shell history

[Ronald P. Hughes]

In article <71 at cascade.ARPA> griff at cascade.UUCP (Peter Griffin) writes:
>If csh was developed BEFORE sh, what shell was it developed under?

Back in the days of Version 6 UNIX, there was a shell (/bin/sh) that
predated the Bourne shell.  I don't know if Steve Bourne was involved
in this earlier shell's development, but his new creation was intended
to be a superset of the old.  Old shell scripts ran successfully with
the Bourne shell, which is why he could get away with replacing the
old shell completely.  Csh could never replace sh because of syntactic
differences which would render old shell scripts obsolete (aside from
subjective differences of opinions as to which shell was "better").

The old shell source was only a few thousand lines long;  you could breeze
through the listings in long evening and have a pretty good idea of what
was going on.

Ronald P. Hughes    Integrated Solutions, Inc., San Jose    pyramid!isieng!ron