mongosh
Help
On this page
This document provides an overview of the help available in
mongosh
.
Tip
When accessing help in mongosh
, you can use the .help()
and
.help
syntaxes interchangeably.
Command Line Help
To see the options for running the mongosh
executable and
connecting to a deployment, use the --help
option from the command line:
mongosh --help
mongosh
Shell Help
To see the list of commands available in the mongosh
console,
type help
inside a running mongosh
console:
help
Database Help
You can view database level information from inside the
mongosh
console:
By default mongosh
shows the current database in the prompt.
You can also see the current database by running the db
command:
db
Show Available Databases
To see the list of databases available to you on the server, use the
show dbs
command:
show dbs
show databases
is an alias for show dbs
.
Tip
The list of databases will change depending on your access
authorizations. For more information on access restrictions for
viewing databases, see listDatabases
.
Show Database Methods
To see the list of database methods you can use on the db
object, run
db.help()
:
db.help()
The output resembles the following abbreviated list:
Database Class: getMongo Returns the current database connection getName Returns the name of the DB getCollectionNames Returns an array containing the names of all collections in the current database. getCollectionInfos Returns an array of documents with collection information, i.e. collection name and options, for the current database. runCommand Runs an arbitrary command on the database. adminCommand Runs an arbitrary command against the admin database. ...
Show Help for a Specific Database Method
To see help for a specific database method in mongosh
, type the
db.<method name>
, followed by .help
or .help()
. The
following example returns help for the db.adminCommand()
method:
db.adminCommand.help()
The output resembles the following:
db.adminCommand({ serverStatus: 1 }): Runs an arbitrary command against the admin database. For more information on usage: https://www.mongodb.com/docs/manual/reference/method/db.adminCommand
Show Additional Usage Details for a Database Method
To see additional usage details for a database method in mongosh
,
type the db.<method name>
without the parenthesis (()
). The
following example returns details about the
db.adminCommand()
method:
db.adminCommand
The output resembles the following:
[Function: adminCommand] AsyncFunction { apiVersions: [ 1, Infinity ], serverVersions: [ '3.4.0', '999.999.999' ], returnsPromise: true, topologies: [ 'ReplSet', 'Sharded', 'LoadBalanced', 'Standalone' ], returnType: { type: 'unknown', attributes: {} }, deprecated: false, platforms: [ 0, 1, 2 ], isDirectShellCommand: false, acceptsRawInput: false, shellCommandCompleter: undefined, help: [Function (anonymous)] Help }
Collection Help
You can view collection level information from inside the
mongosh
console.
These help methods accept a collection name, <collection>
, but you
can also use the generic term, "collection", or even a collection that
does not exist.
List Collections in the Current Database
To see the list of collections in the current database, use the
show collections
command:
show collections
The show collections
output indicates if a collection is a
time series collection or a
read-only view.
managementFeedback [view] survey weather [time-series] system.buckets.weather system.views
In the preceding example:
managementFeedback
is a viewweather
is a time seriessurvey
is a collectionsystem.buckets.weather
is a system generated collection that supports theweather
time seriessystem.views
is a system generated collection that supports views on other collections
Show Collection Methods
To see the list of methods available on collection objects use the
db.<collection>.help()
method:
db.collection.help()
<collection>
can be the name of an existing or non-existent
collection.
The output resembles the following abbreviated list:
Collection Class: aggregate Calculates aggregate values for the data in a collection or a view. bulkWrite Performs multiple write operations with controls for order of execution. count Returns the count of documents that would match a find() query for the collection or view. countDocuments Returns the count of documents that match the query for a collection or view. deleteMany Removes all documents that match the filter from a collection. deleteOne Removes a single document from a collection. ...
Show Help for a Specific Collection Method
To see help for a specific collection method in mongosh
, use
db.<collection>.<method name>
, followed by .help
or
.help()
.
The following example displays help for db.collection.insertOne()
:
db.collection.insertOne.help()
The output resembles the following:
db.collection.insertOne(document, options): Inserts a document into a collection. For more information on usage: https://www.mongodb.com/docs/manual/reference/method/db.collection.insertOne
Show Additional Details for a Collection Method
To see additional details for a collection method type the method name,
db.<collection>.<method>
, without the parenthesis (()
).
The following example returns details about the
insertOne()
method:
db.collection.insertOne
The output resembles the following:
[Function: insertOne] AsyncFunction { apiVersions: [ 1, Infinity ], serverVersions: [ '3.2.0', '999.999.999' ], returnsPromise: true, topologies: [ 'ReplSet', 'Sharded', 'LoadBalanced', 'Standalone' ], returnType: { type: 'unknown', attributes: {} }, deprecated: false, platforms: [ 0, 1, 2 ], isDirectShellCommand: false, acceptsRawInput: false, shellCommandCompleter: undefined, help: [Function (anonymous)] Help }
Cursor Help
To modify read operations that use
find()
, use cursor methods.
To list the available modifier and cursor handling methods, use the
db.collection.find().help()
command:
db.collection.find().help()
This help call accepts a collection name, <collection>
, but you
can also use the generic term, "collection", or even a collection which
does not exist.
Some useful methods for handling cursors are:
hasNext()
checks if the cursor has more documents.next()
returns the next document and moves the cursor position forward by one.forEach(<function>)
applies the<function>
to each document returned by the cursor.
For a list of available cursor methods, see Cursor.
BSON Class Help
mongosh
provides help methods for BSON classes. The
help methods provide a brief overview of the BSON class and a link with
more information.
To access help for BSON classes, run .help()
on either the class
name or an instantiated instance of the class:
<BSON class>.help() // or <BSON class>().help()
For example, to view help for the ObjectId
BSON class, run one of
the following commands:
ObjectId.help()
ObjectId().help()
mongosh
returns the same output for both .help()
methods:
The ObjectId BSON Class: For more information on usage: https://mongodb.github.io/node-mongodb-native/3.6/api/ObjectID.html
mongosh
provides help methods for the following BSON classes:
BinData
Code
DBRef
MinKey
MaxKey
NumberDecimal
NumberInt
NumberLong
ObjectId
Symbol
(Deprecated)Timestamp
Command Helpers
mongosh
provides the following methods and commands to wrap
certain database commands and obtain information on your deployment:
Help Methods and Commands | Description | |
---|---|---|
db.help() | Display help for database methods. | |
db.<collection>.help() | Display help on collection methods. The <collection> can be
the name of an existing collection or a non-existing collection. | |
help | Display help. | |
show collections | Display a list of all collections for current database. | |
show dbs | Display a list of all databases on the server.
| |
show log <name> | Displays the last segment of log in memory for the specified
logger name. If you do not specify a To show
| |
show logs | Display the accessible logger names. See Retrieve Shell Logs. | |
show profile | Display the five most recent operations that took 1 millisecond or
more. See documentation on the
database profiler for more information. | |
show roles | Display a list of all roles, both user-defined and built-in, for
the current database. | |
show tables | Display a list of collections in the current database. See show
collections . | |
show users | Display a list of users for current database. |