start_date=`date -d "20200701" +"%Y%m%d"`
last_date=`date -d "20200710" +"%Y%m%d"`
cur_date=$start_date

date_list=""
while [ $cur_date -le $last_date ];
do
date_list="$date_list $cur_date"
cur_date=`date -d "$cur_date +1 day" +"%Y%m%d"`
done

for monitor_date in $date_list;
do
{
.......
} &
done

wait

echo "Done."