$ winpty docker-compose.exe exec mariadb bash
root@5da26f38c385:/# mysqldump -u root <schema名> -p > /tmp/dump.sql
$ docker ps | grep -E "mariadb|IMAGE"
docker ps | grep -E "mariadb|IMAGE"
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
5da26f38c385 mariadb:10.3.2 "docker-entrypoint.s…" 2 hours ago Up 2 hours 127.0.0.1:3306->3306/tcp xxxxxx_mariadb_1
$ docker cp <コンテナID>:/tmp/dump.sql .