csh script interruptability

[utzoo!decvax!microsof!fluke!jeff]

Suppose you invoke vi from within a csh script, and suppose that you send
an intr signal (usually ^C or `#') to abort the script while you're in vi.

Surprise!
  - Vi drops into the background and develops an enormous appetite for
    cpu cycles.
  - Your terminal characteristics are munged up.

Question of the day:
  How to undo this mess?  You can catch the signal within the
  script and try to put things back in order.  But why can't you kill vi?

For example:

	#! /bin/csh -f
	onintr egress	# Catch them signals and head for the egress.
	vi foo		# Now give a ^C to vi and you'll land
	egress:		# here...
	reset		# Un-mung the terminal.
	echo 'aborting'	# This is important - you'll see later.
	jobs 		# Shows vi chugging away...
	kill -9 %vi	# This ought to blast it.
	echo $status	# Shows that kill ``worked'', but...
	jobs 		# it's still there!

Now you can alter the behavior in significant and interesting ways by changing
the echo statement!
  Exercise 1: Change ``echo ...'' to ``/bin/echo ...''.  Why does this keep vi
  from going bonkers? Note that this doesn't fix everything.  Would you say
  this is an improvement?

P.S. I don't want to place all the blame on vi - you can substitute other
interesting programs as well - such as mail(1).  (Hmmm... what gives, Berkeley?)

	- jeff stearns, john fluke mfg co., everett wa
	  ...!decvax!microsoft!fluke!jeff