# checkqueue.py
while True:
  check_queue()
  do_something()

# keepalivescript.sh
if processidfile exists:
  if processid is running:
     exit, all ok

run checkqueue.py
write processid to processidfile

# crontab
*/5 * * * * /path/to/keepalivescript.sh

until myserver; do
    echo "Server 'myserver' crashed with exit code $?.  Respawning.." >&2
    sleep 1
done

lf = open('/tmp/script.lock','w')
if(fcntl.flock(lf, fcntl.LOCK_EX|fcntl.LOCK_NB) != 0):
   sys.exit('other instance already running')
lf.write('%dn'%os.getpid())
lf.flush()

if [ `flock -xn /tmp/script.lock -c 'echo 1'` ]; then
   echo 'it's not running'
   restart.
else
   echo -n 'it's already running with PID '
   cat /tmp/script.lock
fi

if ! test -f $PIDFILE || ! psgrep `cat $PIDFILE`; then
    restart_process
    # Write PIDFILE
    echo $! >$PIDFILE
fi

while 1
do
/your/script
sleep 1
done

while 1
do
/your/script
sleep 1
done

pid=`jps -v | grep $INSTALLATION | awk '{print $1}'`
echo $INSTALLATION found at PID $pid
while [ -e /proc/$pid ]; do sleep 0.1; done