$ mongo
> help
...
> show dbs
admin  (empty)
demo   0.078GB
local  0.078GB

> use demo      (name of db)
switched to db demo

> show collections
people
system.indexes

> db.people.find()
{ "_id" : ObjectId("58a3e9b2962d747a9c6e676c"), "email" : "foo@example.com", "student" : true, 
    "birthdate" : ISODate("2002-01-02T00:00:00Z"), "name" : "Foo" }
{ "_id" : ObjectId("58a3e9b2962d747a9c6e676d"), "email" : "bar@example.com", "name" : "Bar", "student" : true,
    "birthdate" : ISODate("1998-08-03T00:00:00Z"), "teacher" : false }
{ "_id" : ObjectId("58a3e9b2962d747a9c6e676e"), "email" : "zorg@corp.com",
    "birthdate" : ISODate("1995-12-12T00:00:00Z"), "teacher" : true, "name" : "Zorg" }

> db.people.drop()      (drop a collection)
> db.dropDatabase()     (drop a whole database)