List databases:
echo 'show dbs' | mongo
Delete database:
use mydb
db.dropDatabase()
or:
echo 'db.dropDatabase()' | mongo mydb
View collections within a database:
echo 'db.getCollectionNames()' | mongo mydb
Show all data from one of the collections: stackoverflow.com/questions/24985684/mongodb-show-all-contents-from-all-collections
echo 'db.collectionName.find()' | mongo mydb
Tested as of Ubuntu 20.04, there is no Mongo package available by default due to their change to Server Side Public License, which Debian opposed. Therefore, you have to add their custom PPA as mentioned at: docs.mongodb.com/manual/tutorial/install-mongodb-on-ubuntu/