A quick shell script to dump all your databases and compress them.

dumpdatabases-mysql.sh

USER="root"
PASSWORD=""
OUTPUT="/Users/yourusername/Sites"

ExcludeDatabases="Database|information_schema|performance_schema|mysql|sys"
databases=`mysql -u $USER -p$PASWORD -e "SHOW DATABASES;" | tr -d "| " | egrep -v $ExcludeDatabases`

for database in $databases; do
        echo "Dumping database: $database"
        mysqldump -u $USER -p$PASSWORD --databases $database > `date +%Y%m%d`.$database.sql | gzip $OUTPUT/`date +%Y%m%d`.$database.sql
done