$ apt-get install -y mongodb-org

$ mongo

> db.help()
DB methods:
db.adminCommand(nameOrDocument) - switches to 'admin' db, and runs command [just calls db.runCommand(...)]
db.aggregate([pipeline], {options}) - performs a collectionless aggregation on this database; returns a cursor
db.auth(username, password)
db.cloneDatabase(fromhost)
db.commandHelp(name) returns the help for the command
db.copyDatabase(fromdb, todb, fromhost)
db.createCollection(name, {size: ..., capped: ..., max: ...})
db.createView(name, viewOn, [{$operator: {...}}, ...], {viewOptions})
db.createUser(userDocument)
db.currentOp() displays currently executing operations in the db
db.dropDatabase()
db.eval() - deprecated
db.fsyncLock() flush data to disk and lock server for backups
db.fsyncUnlock() unlocks server following a db.fsyncLock()
db.getCollection(cname) same as db['cname'] or db.cname
db.getCollectionInfos([filter]) - returns a list that contains the names and options of the db's collections
db.getCollectionNames()
db.getLastError() - just returns the err msg string
db.getLastErrorObj() - return full status object
db.getLogComponents()
db.getMongo() get the server connection object
db.getMongo().setSlaveOk() allow queries on a replication slave server
db.getName()
db.getPrevError()
db.getProfilingLevel() - deprecated
db.getProfilingStatus() - returns if profiling is on and slow threshold
db.getReplicationInfo()
db.getSiblingDB(name) get the db at the same server as this one
db.getWriteConcern() - returns the write concern used for any operations on this db, inherited from server object if set
db.hostInfo() get details about the server's host
db.isMaster() check replica primary status
db.killOp(opid) kills the current operation in the db
db.listCommands() lists all the db commands
db.loadServerScripts() loads all the scripts in db.system.js
db.logout()
db.printCollectionStats()
db.printReplicationInfo()
db.printShardingStatus()
db.printSlaveReplicationInfo()
db.dropUser(username)
db.repairDatabase()
db.resetError()
db.runCommand(cmdObj) run a database command.  if cmdObj is a string, turns it into {cmdObj: 1}
db.serverStatus()
db.setLogLevel(level,)
db.setProfilingLevel(level,slowms) 0=off 1=slow 2=all
db.setWriteConcern() - sets the write concern for writes to the db
db.unsetWriteConcern() - unsets the write concern for writes to the db
db.setVerboseShell(flag) display extra information in shell output
db.shutdownServer()
db.stats()
db.version() current version of the server

$ mongodump --out=./dump1

$ mongorestore ./dump1

> db.version()
3.6.3

> show dbs
admin   0.000GB
config  0.000GB
db3     0.000GB
local   0.000GB

> use db5
switched to db db5

> db
db5

> use db5
> db.dropDatabase()

> use dbTest
> db.createCollection('Empl1')
{ "ok" : 1 }
> show collections
Empl1

> db.Empl1.drop()
> show collections

> db.COLLECTION_NAME.insert(document)

> db.createCollection('EmplList')
{ "ok" : 1 }
> db.EmplList.insert({name: 'NAME1', address: 'ADDR1'})
WriteResult({ "nInserted" : 1 })
> db.EmplList.find()
{ "_id" : ObjectId("6778c9d63e90cb7a981b32a5"), "name" : "NAME1", "address" : "ADDR1" }

db.COLLECTION_NAME.update(SELECTION_CRITERIA, UPDATED_DATA)

> db.EmplList.update({name: 'NAME1'},{$set:{'name':'NEW NAME1', 'address': 'NEW ADDR1'}})
> db.EmplList.find()
{ "_id" : ObjectId("6778c9d63e90cb7a981b32a5"), "name" : "NEW NAME1", "address" : "ADDR1" }

> db.EmplList.update({name: 'NEW NAME1'},{$set:{'name':'NEW NAME2', 'address': 'NEW ADDR2'}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.EmplList.find()
{ "_id" : ObjectId("6778c9d63e90cb7a981b32a5"), "name" : "NEW NAME2", "address" : "NEW ADDR2" }

> db.EmplList.update({address: 'NEW ADDR2'},{$set:{'name':'NAME2', 'address': 'ADDR2'}})

> db.COLLECTION_NAME.save({_id:ObjectId(),NEW_DATA})

> db.EmplList.save({"_id": new ObjectId("6778c9d63e90cb7a981b32a6"), name: "NAME_SAVED", address: "ADDR_SAVED"});
> db.EmplList.find()
{ "_id" : ObjectId("6778c9d63e90cb7a981b32a5"), "name" : "NAME2", "address" : "ADDR2" }
{ "_id" : ObjectId("6778c9d63e90cb7a981b32a6"), "name" : "NAME_SAVED", "address" : "ADDR_SAVED" }

> db.COLLECTION_NAME.remove(DELLETION_CRITTERIA)

> db.EmplList.find()
{ "_id" : ObjectId("6778c9d63e90cb7a981b32a5"), "name" : "NAME2", "address" : "ADDR2" }
{ "_id" : ObjectId("6778c9d63e90cb7a981b32a6"), "name" : "NAME_SAVED", "address" : "ADDR_SAVED" }

>db.EmplList.remove({"name" : "NAME_SAVED"})
WriteResult({ "nRemoved" : 1 })

> db.EmplList.find()
{ "_id" : ObjectId("6778c9d63e90cb7a981b32a5"), "name" : "NAME2", "address" : "ADDR2" }