I added TCSH command line editng. The history was you could scroll back
through your previous commands. By default, the thing used an emacs-like
command binding, but it was entirely configurable.
Most of the Mach /bin/sh were my earlier shell with only job control. The
command editing one didn't make Doug's distribution.
I also remember sitting down with some other guys and explaining how the BSD
job control worked. For this garnered me a mention in some of the early
linux docs.
I also remember having a nice discussion of shell internals with Dave Korn
at another show. The two of us had a lot of stories about banging our
heads on the shell internals.
The most significant change out of the labs was between SV and SVR2 when
someone finally got rid of all those Bourne macros that made the C look like
Algol or whatever.