Usage :
If linked, take the env variables DB_NAME, DB_PASS and DB_USER from source container to feed it to this mysql-client container.
docker run --rm -ti --link=:mysql iwdrepo/mysqlclient -e "show databases;"
If not linked, pass it with the -e parameter
docker run --rm -ti -e DB_NAME=<> -e DB_PASS=<> -e DB_USER=<> iwdrepo/mysqlclient -e "show databases;"