On 2/17/06, Michael Moore <[EMAIL PROTECTED]> wrote:
> Hello shell script gurus. I'm sure I'm doing this the hard way...so if
> you could shed some light.
I'm not a guru but I have some ideas. I realize this is a few days
old, but I havne't noticed the options I'm thinking of, so here goes.
Have you thought about using a scripting language? perl would be my
preference, but then that's kind of obvious. :> That way you could
easily flock the pid file and reduce the possibility of the race
condition mentioned.
> I'm trying to write a shell script that will only run if it's not
> running already, and if it is running, kill the other process. ie:
#!/bin/bash
# If the program is already running then kill it and exit
# otherwise process normally.
SCRIPT=`basename $0`
PIDDIR=/var/run
PIDFILE=${PIDDIR}/${SCRIPT}.pid
CONTINUE=y
if [ -e ${PIDFILE} ] # Old process exists
then
PID=`cat ${PIDFILE}`
if [ -z ${PID} ] || [[ ! ${PID} =~ '^[0-9]*$' ]]
then
# something went wrong -- pid is empty or NaN
# delete pidfile and continue normally
echo Empty or corrupted pidfile, deleting, continuing ...
rm ${PIDFILE}
elif [[ ! ${PID} =~ '^[0-9]*$' ]] # see if $PID is a number
then
RUNNING=`ps -p ${PID} -o pid=` # see if it's running
RUNNING=`ps -C ${SCRIPT} -o pid=` # see if other instances are running
for i in ${RUNNING}
do
kill -9 $i
done
echo Process was running, killed, exiting.
rm ${PIDFILE}
exit -1
fi
fi
echo $$ > ${PIDFILE}
echo Normal processing here
rm ${PIDFILE}
exit 0
--
Alan
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