How to Use mongosh: MongoDB Shell Basics and Examples

Use mongosh to start the MongoDB shell, which lets you connect to your database and run commands interactively. Simply open your terminal and type mongosh to connect to the default local MongoDB server or specify a connection string to connect remotely.

Syntax

The basic syntax to start the MongoDB shell is:

• mongosh: Connects to the local MongoDB server on default port 27017.
• mongosh <connection-string>: Connects to a remote or specific MongoDB instance using a connection string.
• Inside the shell, you can run commands like show dbs to list databases or db.collection.find() to query data.

bash

mongosh

mongosh "mongodb+srv://username:[e-mail]/myDatabase"

Example

This example shows how to start mongosh, list databases, switch to a database, and query a collection.

mongodb

mongosh
> show dbs
> use test
> db.users.find()

Output

test  0.000GB
admin 0.000GB
local 0.000GB
switched to db test
[ { _id: ObjectId("..."), name: "Alice", age: 25 }, { _id: ObjectId("..."), name: "Bob", age: 30 } ]

Common Pitfalls

Common mistakes when using mongosh include:

• Not having MongoDB server running before starting mongosh, which causes connection errors.
• Using the old mongo shell command instead of mongosh, which is deprecated.
• Incorrect connection strings causing authentication failures.
• Forgetting to switch to the correct database with use <dbname> before running queries.

bash

Wrong:
mongo

Right:
mongosh

Wrong:
mongosh "mongodb://wrongUser:wrongPass@localhost:27017"

Right:
mongosh "mongodb://correctUser:correctPass@localhost:27017"

Quick Reference

Command	Description
mongosh	Start MongoDB shell and connect to local server
mongosh	Connect to remote MongoDB server
show dbs	List all databases
use	Switch to a specific database
db.collection.find()	Query documents in a collection
exit	Exit the shell

Key Takeaways

Start mongosh by typing mongosh in your terminal to connect to MongoDB.

Use mongosh <connection-string> to connect to remote databases securely.

Always ensure your MongoDB server is running before starting mongosh.

Switch to the correct database with use <dbname> before running queries.

Avoid using the deprecated mongo shell; use mongosh instead.