# MongoDB: shell commands examples
Here are examples of common operations within the MongoDB Shell (mongosh):
1. Database Management:
show databases.
JavaScript
``` show dbs ```
- **Switch to a database (or create if it doesn't exist):**
JavaScript
``` use myDatabase ```
Show current database.
JavaScript
``` db ```
2. Collection Management:
Show collections in the current database.
JavaScript
``` show collections ```
Create a new collection.
JavaScript
``` db.createCollection("myCollection") ```
3. Data Manipulation (CRUD Operations):
Insert a single document.
JavaScript
``` db.myCollection.insertOne({ name: "Alice", age: 30, city: "New York" }) ```
Insert multiple documents.
JavaScript
``` db.myCollection.insertMany([ { name: "Bob", age: 25, city: "London" }, { name: "Charlie", age: 35, city: "Paris" } ]) ```
Find all documents in a collection.
JavaScript
``` db.myCollection.find() ```
Find documents with specific criteria.
JavaScript
``` db.myCollection.find({ age: { $gt: 28 } }) // Find documents where age is greater than 28 ```
Find documents and project specific fields.
JavaScript
``` db.myCollection.find({}, { name: 1, city: 1, _id: 0 }) // Include name and city, exclude _id ```
Update a single document.
JavaScript
``` db.myCollection.updateOne({ name: "Alice" }, { $set: { age: 31 } }) ```
Update multiple documents.
JavaScript
``` db.myCollection.updateMany({ city: "London" }, { $set: { status: "active" } }) ```
Delete a single document.
JavaScript
``` db.myCollection.deleteOne({ name: "Bob" }) ```
Delete multiple documents.
JavaScript
``` db.myCollection.deleteMany({ status: "inactive" }) ```
4. Utility Commands:
Clear the shell screen.
JavaScript
``` cls ```
exit the shell.
JavaScript
``` exit ```