mysql backup with rotate

#!/bin/sh

# Parameters
HOST="localhost"
USER="user"
PASS="pass"
DB="database"
DDIR="/home/username/dbbackup"
D=`date +%Y%m%d`
DUMP="mysqldump -h $HOST -u $USER -p $PASS $DB"

# functions
function job {
  $DUMP | gzip > $DDIR/$DB-$D.sql.gz
  find $DDIR -mtime +7 -type f -iname "*.sql.gz" -exec rm -f {} \;
}

# action
job 

# test by creating some files and executing the script
# touch -t <date ex: 201010190830> <filename>