while ["a"="a"]
do lsth=$(date +"%H")
    lstm=$(date +"%M")
    if [$lsth = "00" && ($lstm="30" || $lstm="35" || $lstm="40" || $lstm="45")]
      echo "run process at $date"
    fi
done



      [$lasttime = "0935"] 

lasthour=$(date +"%Y%m%d%H%M")
newhour=$(date +"%Y%m%d%H%M")
while test $newhour = $lasthour
do echo "  new hour = $newhour"
    sleep 1
    newhour=$(date +"%Y%m%d%H%M")
done
echo "hour changed:"
echo "  last hour = $lasthour"
echo "  new  hour = $newhour"