Dump all databases without except system databases.

db_dump.sh

#!/bin/bash

host=<DB_HOST>
password=<DB_PASSWORD>
user=<DB_USER>

database=( $(mysql -h $host -u $user -p$password -e "SHOW DATABASES;" | grep -Ev "(Database|information_schema|mysql|performance_schema|tmp|sys)") )
for db in "${database[@]}"
do
       mysqldump -h $host -u $user -p$password $db > $db.sql
       echo "dumping $db....."
done