Full duplex connections (pipes)

[Conrad Hughes <chughes@maths.tcd.ie>]

Roger Peppe writes:

>would a full duplex connection really be useful when used
>from a shell ?
Many moons ago I suggested that it would be nice if you could background
a process and communicate with it from your command line, thus allowing
an MH-like interface to be plugged into any process you wanted - these
might include dbx (useful), bc (less so since you can execute it with
a minimum of hassle anyway), gnuplot and any other application which
has its own command line interpreter.  More recently this was brought
up again by Colman Reilly (another maths.tcd.ie person), but the idea
didn't generate much response either time.  Seeing this comment about
applications assuming stdin/out/err as 0/1/2, it's not inconceivable
that the entire idea is impossible for a very simple and logical reason,
and that everybody in the know just sniggers and ignores it.  I've never
heard this reason and I'm not expert enough to discover it myself without
a chunk of work which I just haven't done.

So please - any comments?

Conrad