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From: richl@penguin.USS.TEK.COM (Rick Lindsley)
Newsgroups: comp.unix.questions
Subject: Re: Problem with rcp/rsh/rdump
Message-ID: <95@puffin.USS.TEK.COM>
Date: Fri, 9-Oct-87 19:22:03 EDT
Article-I.D.: puffin.95
Posted: Fri Oct  9 19:22:03 1987
Date-Received: Mon, 12-Oct-87 02:42:43 EDT
References: <441@nysernic> <759@gargoyle.UChicago.EDU> <2696@xanth.UUCP>
Sender: nobody@puffin.USS.TEK.COM
Reply-To: richl@penguin.USS.TEK.COM (Rick Lindsley)
Organization: Tektronix, Inc., Beaverton, OR.
Lines: 42
Keywords: Where are you?

In <759@gargoyle.UChicago.EDU>, chris@gargoyle.UChicago.EDU writes:
> # 
> # Check to see if this is an interactive shell...
> if ($?prompt) then
>  ...
> endif

In article <2696@xanth.UUCP> kyle@xanth.UUCP (Kyle Jones) adds:

> An oft missed optimization of this is
> 
> if ($?prompt == 0) exit 0
> 
> which allows csh to skip parsing the rest of the file.

This may not be such a good idea. Remember the shell is sourcing this
file; telling it to exit may not be what you want at all. Let me present
a worst case scenario. I was having trouble figuring out why a shell script
was not working correctly:

while true
do
    stuff
done

"Stuff" was never getting done. Turns out a combination of two things
were happening. The user's .cshrc had a line in that said

if ($?prompt == 0) exit 1

and /bin/true was

--
#
# id string here
#
exit 0
--

Use your wizardry to see the bug here.

Rick