cronnjob for backup

# vi /bin/backup.sh

#!/bin/sh

#backup.sh

ldir=$(mysqldump -u host -p pwd dbname > /test.COM/public_html/backups/dbname _`date +"\%Y\%m\%d\%H\%M\%S"`.sql);

$wq!

then scheduled cronnjob for backup for every 30 minutes 

# vi /etc/crontab

*/30 * * * * root /bin/backup.sh

$wq!