Date: Sat, 13 Aug 2005 05:18:21 +1000 (EST) From: Ian Smith <smithi@nimnet.asn.au> To: freebsd-questions@freebsd.org Cc: Xu Qiang <Qiang.Xu@fujixerox.com> Subject: Help on bash script? Message-ID: <Pine.BSF.3.96.1050813044601.8009A-100000@gaia.nimnet.asn.au> In-Reply-To: <20050812013604.8C12D16A422@hub.freebsd.org>
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On Fri 12 Aug 2005 09:33:54 +0800 Xu Qiang <Qiang.Xu@fujixerox.com> wrote:
> find / -type f -name core -print | while read COREFILE ; do
> NCOREFILES=$[ $NCOREFILES + 1 ] # a bit strange - xq
> echo $NCOREFILES # xq
>
> NEWNAME="${HOSTNAME}esscore${NCOREFILES}_${TIMESTAMP}"
> # record mapping so people can go back and figure out
> # where they came from
> echo -e $NEWNAME " was " `ls -l $COREFILE` >> $SAVE_DIR/$CORELOG
> mv $COREFILE $SAVE_DIR/$NEWNAME
>
> echo "There are $NCOREFILES core files." # xq
> done
>
> fi
>
> # What confused me most is the value $NCOREFILES outside
> # the do-while loop (but still in this function) reverted
> # back to its initial value, which seems contradictory to
> # our concept of local variables. - xq
> #echo $NCOREFILES
It's been pointed out that the find piped to while runs in a subshell,
and that changes to variables within aren't seen by its parent, but one
way around this is to avoid using a pipe, thus a subshell, for instance:
find / -type f -name "*.core" -print >tempfile
while read COREFILE; do
[.. stuff ..]
NCOREFILES=$(($NCOREFILES + 1))
done <tempfile
echo $NCOREFILES
I use sh, not bash, but suspect that this should work in bash too.
cheers, Ian
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