See this page for more details on how to install MongoDB:
https://docs.mongodb.com/manual/installation/

$ sudo apt update $ sudo apt install -y mongodb-org
Enable mongod server service:
$ sudo systemctl enable mongod.service $ sudo systemctl start mongod.service
Check installation:
$ mongo --version MongoDB shell version v4.2.0 git version: a4b751dcf51dd249c5865812b390cfd1c0129c30 OpenSSL version: OpenSSL 1.1.1 11 Sep 2018 allocator: tcmalloc modules: none build environment: distmod: ubuntu1804 distarch: x86_64 target_arch: x86_64
Configuration files:

• Binary file: /usr/bin/mongod
  
  
• Configuration file: /etc/mongod.conf
  
  
• DB path: /var/lib/mongodb/
  
  
• Log file: /var/log/mongodb/mongod.log
  

Start MongoDB as a service: $ sudo service mongod start
Start MongoDB as a process using "config" paramter: $ nohup /usr/bin/mongod --config /etc/mongod.conf &
Start MongoDB as a process using "dbpath" paramter: $ nohup /usr/bin/mongod --dbpath /var/lib/mongodb &
Verify MongoDB status: $ sudo service mongod status
Verify MongoDB process: $ ps -ef | grep mongodb mongodb 1517 /usr/bin/mongod --config /etc/mongod.conf
List active connections: $ lsof -i | grep mongo
$ netstat -l | grep 27017 tcp 0 0 localhost:27017 0.0.0.0:* LISTEN unix 2 [ ACC ] STREAM LISTENING 1391442 /tmp/mongodb-27017.sock
Stop MongoDB: $ sudo service mongod stop

Uninstall MongoDB: $ sudo service mongod stop $ sudo apt purge mongodb-org* $ sudo apt autoremove $ sudo rm -r /var/log/mongodb $ sudo rm -r /var/lib/mongodb

Create a user/password on a specific database: $ mongo
If you don't connect to a specific database, the user will be created on the "test" database: > use mymdb
Create the user: > db.createUser( { user: "user1", pwd: "pwd1", roles: [ { role: "dbOwner", db: "mymdb" } ] } ) Successfully added user: { "user" : "user1", "roles" : [ { "role" : "dbOwner", "db" : "mymdb" } ] }
Verify user creation: > use mymdb switched to db mymdb > db.auth("user1", "pwd1") 1
Test user connection: $ mongo -u user1 -p pwd1 mymdb > db.getUser("user1") { "_id" : "mymdb.user1", "userId" : UUID("59ace827-0b71-4674-a2cd-82ad6fd004d1"), "user" : "user1", "db" : "mymdb", "roles" : [ { "role" : "dbOwner", "db" : "mymdb" } ], "mechanisms" : [ "SCRAM-SHA-1", "SCRAM-SHA-256" ] }
List all users of a database: > use mymdb > db.getUsers()
Delete a user: > use mymdb > db.dropUser('user1')

$ mongo
> use admin switched to db admin
> show collections system.users system.version
> db.system.users.find() { "_id": "mymdb.user1", "userId": UUID("b79c29e7-2ec8-41fa-924b-b08b6c33549d"), "user": "user1", "db": "mymdb", "credentials": { "SCRAM-SHA-1": { "iterationCount": 10000, "salt": "vb85F7h2TomgGGm7mw3ksw==", "storedKey": "rQ0GGHBN0affRBFGe3Wvm4Yrgfg=", "serverKey": "yKnztyYNJW15tH/nBte/h01tD0A=" }, "SCRAM-SHA-256": { "iterationCount": 15000, "salt": "yPFiaRmV9ffKw7iZU+ROP/uLVb1w9/X1lwrF4A==", "storedKey": "5Mlt6bA9p6dP+xch5hI6NItes0fmyHF9lIiYu5euXgs=", "serverKey": "a1Hwo5Cyc8E6vQGDpqxR1wRLuSZ6qEU3VCeZAh8QH3M=" } }, "roles": [ { "role": "dbOwner", "db": "mymdb" } ] }
> db.system.version.find() { "_id" : "featureCompatibilityVersion", "version" : "4.2" }

$ mongo
> use mymdb
> db.createCollection("mycollection")
> show collections mycollection
> db.mycollection.find({},{_id:1})
> db.mycollection.find()

> db.getMongo()
> show users > db.getUsers() > db.getUser("user1")
> show roles
> db.dropUser("user1")
> show databases > show dbs > db.getMongo().getDBNames() > db.adminCommand("listDatabases")
> use mymdb > db.getName()
> db.dropDatabase()
> show collections > db.getCollectionNames() > db.createCollection("mycollection")
> show tables
> db.mycollection.find() > db.mycollection.findOne() > db.mycollection.find().limit(10) > db.mycollection.count();
> db.mycollection.dataSize() > db.mycollection.storageSize() > db.mycollection.totalIndexSize() > db.mycollection.totalSize()
> db.printCollectionStats() > db.mycollection.stats()

List databases: $ mongo --quiet --eval "printjson(db.adminCommand('listDatabases'))" { "databases" : [ { "name" : "admin", "sizeOnDisk" : 176128, "empty" : false }, { "name" : "config", "sizeOnDisk" : 110592, "empty" : false }, { "name" : "local", "sizeOnDisk" : 73728, "empty" : false }, { "name" : "mymdb", "sizeOnDisk" : 8192, "empty" : false } ], "totalSize" : 368640, "ok" : 1 }
List collections names of a specific database: $ mongo -u user1 -p pwd1 mymdb --quiet --eval "printjson(db.getCollectionNames())" [ "mycollection" ]

Configuration file: /etc/mongod.conf # network interfaces net: port: 27017 bindIp: 127.0.0.1,192.168.2.33 # Comment to listen on all interfaces. security: authorization: enabled
Test connection: $ mongo --host localhost --port 27017 -u user1 -p pwd1 mymdb

Remove mongodb-org package: Uninstall MongoDB

Remove the existing mongodb.list:
$ sudo rm /etc/apt/sources.list.d/mongodb*.list
Create the MongoDB repository list file:
$ echo "deb [arch=amd64] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-4.2.list
If you execute the command "apt update" you might get the following error:
W: GPG error: https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 4B7C549A058F8B6B E: The repository 'https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 Release' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default.
So first, you need to add the MongoDB key:
$ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 4B7C549A058F8B6B Executing: /tmp/apt-key-gpghome.r2EHiLZD0B/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com:80 --recv 4B7C549A058F8B6B gpg: key 4B7C549A058F8B6B: public key "MongoDB 4.2 Release Signing Key <packaging@mongodb.com>" imported gpg: Total number processed: 1 gpg: imported: 1
Install MongoDB:
$ sudo apt update $ sudo apt install -y mongodb-org
You can find the MongoDB puclic key ("4B7C549A058F8B6B") by visiting the Ubuntu key server http://keyserver.ubuntu.com

• Enter the "OpenPGPkeyserver": MongoDB
  
• Click "Search Key".
  
• In the search result page, find the version "4.2" and look for the last up-to-date key.