Multiprocessesing, operators

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

I've a couple of questions which spring to mind from the existing
documentation while I droolingly await a manual entry..

It seems possible to have the shell controlling some kind of
multiprocessing communications thingy (vaguely along the lines of
ksh, or so I'm told) - e.g. start up a background process, when the
user enters a particular command the arguments are fed through as
input to this process and output is spewed back to the terminal.  Is
this interpretation correct?

I suspect that this is asking too much, but could it be possible to
dynamically add operators to es?

Conrad