Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site utcsri.UUCP
Path: utzoo!utcsri!tarvydas
From: tarvydas@utcsri.UUCP (Paul Tarvydas)
Newsgroups: net.unix-wizards
Subject: bourne shell "read" vs. hangup trap (1)
Message-ID: <1681@utcsri.UUCP>
Date: Sat, 23-Nov-85 18:13:44 EST
Article-I.D.: utcsri.1681
Posted: Sat Nov 23 18:13:44 1985
Date-Received: Sat, 23-Nov-85 18:17:12 EST
Distribution: net
Organization: CSRI, University of Toronto
Lines: 20

On the two machines which I've tried this, a "hangup" trap does not
cause the (Bourne) shell's "read" command to abort.  Instead, the
shell script continues to execute and sucks up inordinate amounts of
cpu time.  What would be a more appropriate way to code up a "read"
from the keyboard, while maintaining the ability to die gracefully
when a hangup comes by?

The problem can be summarized with the following test script.  I would
have expected the script to terminate after updating "hangup.LOG" when
a hangup trap occurs - this does not appear to be the case.

#!/bin/sh
trap "date >>hangup.LOG; exit 1" 1 2 3 15
while true
do
        read junk
done

Paul Tarvydas
...!utcsri!tarvydas