🚀 go-pugleaf

I am pursuing effective command-line spelling correction for Unix.
Such a system would ideally increase user-efficiency for two major 
reasons.  The users would not be spending time and becoming frustrated 
correcting trivial slips.  Also, they could preserve their 
train of thought on the task at hand instead of the computer details.

I have already implemented two such systems, but neither have been
very effective.  The first system was tested on computer novices
through the University of Maryland Psychology subject pool.  
The second was aimed at more Unix-knowledgeable users.
There seem to have been two significant problems with both of these
systems: 1) the user felt out of control and 2) the output was
too verbose.

The most difficult problem is the interplay of user control and
preserving task train of thought.  Ben Shneiderman brought up an 
analogy for this problem: In word procesors the spelling correction
is not usually made immediately.  We both assume this is largely so
that the user stays in control.  The second system
that I implemented waited until a return was hit, then, if a 
slip was made, produced a corrected line and asked for confirmation.
Here, the user can keep typing even when he or she knows a slip was made, 
simply assuming that the correction will be made.  The problem is 
the user is not totally in control.  Another extreme might be to check 
every blank-terminated word immediately, and just beep when the user
seems to make a mistake.  Here, the user will more easily break
her or his train of thought.

Any comments on command-line spelling correction in general?
Any comments on how to balance user control/task train of thought?
Would anyone be interested in using the next (Sun) system?