mongo Shell Quick Reference
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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 |
--nodb |
Start To connect later, see Opening New Connections. |
--shell |
Used in conjunction with a JavaScript file (i.e. <file.js>) to continue in the 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. |
db.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 You can perform operations on the |
db.collection.find() |
Find all documents in the collection and returns a cursor. See the See Iterate a Cursor in the mongo Shell for information on cursor handling in the |
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. |
db.collection.save() |
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 |
Queries
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 |
---|---|
db.collection.find(<query>) |
Find the documents matching the The following example selects the documents in the For more information on specifying the |
db.collection.find(<query>, <projection>) |
Find documents matching the The following example selects all documents from the collection but returns only the For more information on specifying the |
db.collection.find().sort(<sort order>) |
Return results in the specified The following example selects all documents from the collection and returns the results sorted by the |