# Dump remote database to a local folder
mongodump --uri "mongodb+srv://username:password@host/mydb" --out ./myfolder

# Restore the database from the folder to localhost
mongorestore --port 27017 ./myfolder

# (Restore back to the remote)
mongorestore --host=example.com --port=27017 -u username -p password --db mydb ./myFolder

db.copyDatabase("DATABASENAME", "DATABASENAME", "localhost:27018");