cd ~/backup-mysql/
-DATABASES="$(echo 'show databases' | mysql | tail -n+2)"
+DATABASES="$(echo 'show databases' | mysql | grep -vE '^(Database|mysql|information_schema|performance_schema)$')"
for db in ${DATABASES}; do
mysqldump --add-drop-table --single-transaction "${db}" | \
gzip -9 > "${db}-$(date '+%Y%m%d').sql.gz"