How to list all databases in the mongo shell?

Question

Listing all the databases in mongoDB console is using the command show dbs.

For more information on this, refer the Mongo Shell Command Helpers that can be used in the mongo shell.

For database list:

show databases
show dbs

For table/collection list:

show collections
show tables
db.getCollectionNames()

For MongoDB shell version 3.0.5 insert the following command in the shell:

db.adminCommand('listDatabases')

or alternatively:

db.getMongo().getDBNames()

From the command line issue

mongo --quiet --eval  "printjson(db.adminCommand('listDatabases'))"

which gives output

{
    "databases" : [
        {
            "name" : "admin",
            "sizeOnDisk" : 978944,
            "empty" : false
        },
        {
            "name" : "local",
            "sizeOnDisk" : 77824,
            "empty" : false
        },
        {
            "name" : "meteor",
            "sizeOnDisk" : 778240,
            "empty" : false
        }
    ],
    "totalSize" : 1835008,
    "ok" : 1
}

To list mongodb database on shell

 show databases     //Print a list of all available databases.
 show dbs   // Print a list of all databases on the server.

Few more basic commands

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.