Unusual Exit Behavior

Martin McCormick martin at dc.cis.okstate.edu
Wed Jan 22 19:47:06 UTC 2014

	The strangest thing just happened on a FreeBSD9.1
system. I had used ssh to access this system in command-line
mode from a Linux platform running screen so it is possible that
the behavior came from either the Linux box or the FreeBSD system
but here is what happened.

	I was on the FreeBSD system in bash, testing a perl
script I was writing and I called calc to tell me the answer to
a simple subtraction problem. It gave me the answer but then
there was no shell prompt. Thinking this was odd, I hit Return a
couple of times with nothing so I typed Control-C and got a
message stating something like "abort level 1." Each Control-C I
typed incremented the abort level until at about 3 or 4, I did
get the shell prompt back.

	Every time I ran calc, I got that behavior. I could
short-circuit the odd exit by typing Control-D, but calc
wouldn't just end like it always does if you type something like

calc 86400-3600

I finally caused screen on the Linux box to exit, killing all
the open sessions and when I restarted screen again and
re-connected to the same FreeBSD box, everything was totally
back to normal.

	I am pretty sure I set something that thankfully unset
after the logout, but what could it have been?

I don't really think this had anything to do with calc but at
this stage, I would believe just about anything.

	I have been using unix for about 22 years and I am not
sure I have ever seen this before.

Martin McCormick

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