mongo Shell Quick Reference

mongo Shell Command History

You can retrieve previous commands issued in the mongo shell with the up and down arrow keys. Command history is stored in ~/.dbshell file. See .dbshell for more information.

Command Line Options

The mongo shell can be started with numerous options. See mongo shell page for details on all available options.

The following table displays some common options for mongo:

Option Description
--help Show command line options

Start mongo shell without connecting to a database.

To connect later, see Opening New Connections.


Used in conjunction with a JavaScript file (i.e. <file.js>) to continue in the mongo shell after running the JavaScript file.

See JavaScript file for an example.

Command Helpers

The mongo shell provides various help. The following table displays some common help methods and commands:

Help Methods and Commands Description
help Show help. Show help for database methods.
db.<collection>.help() Show help on collection methods. The <collection> can be the name of an existing collection or a non-existing collection.
show dbs Print a list of all databases on the server.
use <db> Switch current database to <db>. The mongo shell variable db is set to the current database.
show collections Print a list of all collections for current database
show users Print a list of users for current database.
show roles Print a list of all roles, both user-defined and built-in, for the current database.
show profile Print the five most recent operations that took 1 millisecond or more. See documentation on the database profiler for more information.
show databases Print a list of all available databases.
load() Execute a JavaScript file. See Write Scripts for the mongo Shell for more information.

Basic Shell JavaScript Operations

The mongo shell provides a JavaScript API for database operations.

In the mongo shell, db is the variable that references the current database. The variable is automatically set to the default database test or is set when you use the use <db> to switch current database.

The following table displays some common JavaScript operations:

JavaScript Database Operations Description
db.auth() If running in secure mode, authenticate the user.
coll = db.<collection>

Set a specific collection in the current database to a variable coll, as in the following example:

coll = db.myCollection;

You can perform operations on the myCollection using the variable, as in the following example:


Find all documents in the collection and returns a cursor.

See the db.collection.find() and Query Documents for more information and examples.

See Iterate a Cursor in the mongo Shell for information on cursor handling in the mongo shell.

db.collection.insertOne() Insert a new document into the collection.
db.collection.insertMany() Insert multiple new documents into the collection.
db.collection.updateOne() Update a single existing document in the collection.
db.collection.updateMany() Update multiple existing documents in the collection. Insert either a new document or update an existing document in the collection.
db.collection.deleteOne() Delete a single document from the collection.
db.collection.deleteMany() Delete documents from the collection.
db.collection.drop() Drops or removes completely the collection.
db.collection.createIndex() Create a new index on the collection if the index does not exist; otherwise, the operation has no effect.
db.getSiblingDB() Return a reference to another database using this same connection without explicitly switching the current database. This allows for cross database queries.

For more information on performing operations in the shell, see:

Keyboard Shortcuts

The mongo shell provides most keyboard shortcuts similar to those found in the bash shell or in Emacs. For some functions mongo provides multiple key bindings, to accommodate several familiar paradigms.

The following table enumerates the keystrokes supported by the mongo shell:

Keystroke Function
Up-arrow previous-history
Down-arrow next-history
Home beginning-of-line
End end-of-line
Tab autocomplete
Left-arrow backward-character
Right-arrow forward-character
Ctrl-left-arrow backward-word
Ctrl-right-arrow forward-word
Meta-left-arrow backward-word
Meta-right-arrow forward-word
Ctrl-A beginning-of-line
Ctrl-B backward-char
Ctrl-C exit-shell
Ctrl-D delete-char (or exit shell)
Ctrl-E end-of-line
Ctrl-F forward-char
Ctrl-G abort
Ctrl-J accept-line
Ctrl-K kill-line
Ctrl-L clear-screen
Ctrl-M accept-line
Ctrl-N next-history
Ctrl-P previous-history
Ctrl-R reverse-search-history
Ctrl-S forward-search-history
Ctrl-T transpose-chars
Ctrl-U unix-line-discard
Ctrl-W unix-word-rubout
Ctrl-Y yank
Ctrl-Z Suspend (job control works in linux)
Ctrl-H (i.e. Backspace) backward-delete-char
Ctrl-I (i.e. Tab) complete
Meta-B backward-word
Meta-C capitalize-word
Meta-D kill-word
Meta-F forward-word
Meta-L downcase-word
Meta-U upcase-word
Meta-Y yank-pop
Meta-[Backspace] backward-kill-word
Meta-< beginning-of-history
Meta-> end-of-history


In the mongo shell, perform read operations using the find() and findOne() methods.

The find() method returns a cursor object which the mongo shell iterates to print documents on screen. By default, mongo prints the first 20. The mongo shell will prompt the user to “Type it” to continue iterating the next 20 results.

The following table provides some common read operations in the mongo shell:

Read Operations Description

Find the documents matching the <query> criteria in the collection. If the <query> criteria is not specified or is empty (i.e {} ), the read operation selects all documents in the collection.

The following example selects the documents in the users collection with the name field equal to "Joe":

coll = db.users;
coll.find( { name: "Joe" } );

For more information on specifying the <query> criteria, see Specify Equality Condition.

db.collection.find(<query>, <projection>)

Find documents matching the <query> criteria and return just specific fields in the <projection>.

The following example selects all documents from the collection but returns only the name field and the _id field. The _id is always returned unless explicitly specified to not return.

coll = db.users;
coll.find( { }, { name: true } );

For more information on specifying the <projection>, see Project Fields to Return from Query.

db.collection.find().sort(<sort order>)

Return results in the specified <sort order>.

The following example selects all documents from the collection and returns the results sorted by the name field in ascending order (1). Use -1 for descending order: