How do I drop a MongoDB database from the command line ?

We can use the following code:

mongo <dbname> --eval "db.dropDatabase()"

Further details on scripting the shell from the below link:

https://docs.mongodb.com/manual/tutorial/write-scripts-for-the-mongo-shell/#scripting

This is the excellent way to do it from mongodb console:

> use mydb;
> db.dropDatabase();

Here another, we can stop mongod and delete the data files from your data directory, then restart.

Tips: we can also move the data files to a subfolder, and delete them if we are sure you no longer need them.

Here there is no need of heredocs or eval,mongo itself can act as an interpreter.

#!/usr/bin/env mongo
var db = new Mongo().getDB("someDatabase");
db.dropDatabase();

Create the file executable and run it.