Date: Wed, 4 Dec 2019 18:13:00 +0100 From: Polytropon <freebsd@edvax.de> To: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Counter in sh inside loop, value "encapsulation" Message-ID: <20191204181300.8dd0e03c.freebsd@edvax.de>
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In a sh script, I have a counter inside an interator.
The iterator is fed by piping with some greo output.
It looks like this:
#!/bin/sh
# ...
# ... lots of boring stuff omitted ...
# ...
echo "Start: ${TIMESTAMP}"
echo "Input: ${INFILE} (${TOTAL} entries, ${SKIPPED} skipped, ${REMAINING} remaining)"
COUNT=0
grep "^https" ${INFILE} | while read URL; do
COUNT=`expr ${COUNT} + 1`
echo
echo " ${COUNT} / ${REMAINING}"
echo "---> ${URL}"
# ...
# ... processing per URL, also boring ...
# ...
done
echo
echo "URLs processed: ${COUNT}" # <--- (!) THIS IS ZERO!
echo -n "Time: ${TIMESTAMP} - "
date "+%Y-%m-%d %H%:%M:%S"
echo ""
exit 0
So while the loop runs, the counter is increased for
each URL which is processed. After leaving the loop,
$COUNT is zero, for example:
Input: bla.txt (20 entries, 15 skipped, 5 ermaining)
1 / 5
2 / 5
3 / 5
4 / 5
5 / 5
URLs processed: 0
The correct response should be: "URLs processed: 5".
Obviously, I fail to understand something important,
and that is not an acceptable option. :-)
I assume this is some problem due to subshell calling,
maybe because of "grep | while". If I set COUNT=100
before the loop, it'll be 100 after it finishes.
How can I have the final value of $COUNT _outside_ the
loop for the final status message? Note that $COUNT
will receive error checking, so it won't end at the
same value as $REMAINING if something goes wrong, i. e.,
the +1 won't happen if the processing step does not
successfully terminate and leave a $? -eq 0. But I
won't add that check unless I can get the correct
value at the end... :-)
--
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...
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