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Run Commands

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  • Format Input and Output
  • Switch Databases
  • Terminate a Running Command
  • Command Exceptions
  • Clear the mongosh Console

To run commands in mongosh, you must first connect to a MongoDB deployment.

Format Input and Output

mongosh uses the Node.js BSON parser parser to parse BSON data. You can use the parser's EJSON interface to transform your data when you work with mongosh.

For examples that use EJSON, see: EJSON.

Switch Databases

To display the database you are using, type db:

db

The operation should return test, which is the default database.

To switch databases, issue the use <db> helper, as in the following example:

use <database>

To access a different database from the current database without switching your current database context, see the db.getSiblingDB() method.

To list the databases available to the user, use the helper show dbs.

Create a New Database and Collection

To create a new database, issue the use <db> command with the database that you would like to create. For example, the following commands create both the database myNewDatabase and the collection myCollection using the insertOne() operation:

use myNewDatabase
db.myCollection.insertOne( { x: 1 } );

If a collection does not exist, MongoDB creates the collection when you first store data for that collection.

Terminate a Running Command

To terminate a running command or query in mongosh, press Ctrl + C.

When you enter Ctrl + C, mongosh:

  • interrupts the active command,

  • tries to terminate the ongoing, server-side operation, and

  • returns a command prompt.

If mongosh cannot cleanly terminate the running process, it issues a warning.

Note

Pressing Ctrl + C in mongosh does not terminate asynchronous code. Asynchronous operations such as setTimeout or operations like fs.readFile continue to run.

There is no way to terminate asynchronous code in mongosh. This is the same behavior as in the Node.js REPL.

Pressing Ctrl + C once will not exit mongosh, press Ctrl + C twice to exit mongosh.

You can also terminate a script from within the script code by calling the exit(<code>) command. For more information, refer to Terminate a Script on Error.

Command Exceptions

In scenarios where the output of a command includes { ok: 0 }, mongosh throws an exception and does not return the raw output from the server.

Note

In the legacy mongo shell, when a command's output included { ok: 0 }, the behavior differs between commands. mongosh provides consistent behavior by always throwing an exception in these scenarios.

Clear the mongosh Console

The cls command clears the console. You can also clear the console with Ctrl + L and console.clear().

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