Odd vi response when input redirected

[Ray Swartz]

On System V machines, the command

	cat | vi

works fine.  [On BSD systems, vi gives an error message and won't work properly]
The benefit of redirecting the input of vi is that you can put your own
process in place of cat and implement a "hot key" function for vi.  On my
system, the hot key (a ctrl-A) displays a vi help menu for novice users.

The hot key works great.  The problem is that now the shell escape doesn't
work properly.  When I enter :!cmd, the command appears to be run, but the
output doesn't go the the terminal.  For example, :!ls produces no output.

This seems like odd behaviour since only the input of vi has been redirected.

Where does the output of the !cmds go?  BTW, I tried !cmd > /dev/tty
but that didn't do anything either.

Thanks in advance.

Ray Swartz

I've noticed an odd vi feature and don't know why it reacts the way it does.