how to install mongodb ubuntu

First import public key of 10gen repository in our system

 sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10

For Ubuntu:

echo 'deb http://downloads-distro.mongodb.org/repo/ubuntu-upstart dist 10gen' | sudo tee /etc/apt/sources.list.d/mongodb.list

sudo apt-get update
sudo apt-get install mongodb-org

install robomongo app

sudo apt-get install robomongo-0.8.4-i386$
tar xvfz robomongo-0.8.4-i386.tar.gz
 robomongo-0.8.4-i386/bin$ ./robomongo

ubuntu@ubuntu:~$ sudo service mongod stop
mongod stop/waiting
ubuntu@ubuntu:~$ sudo service mongod start
mongod start/running, process 19201
ubuntu@ubuntu:~$ mongo --version
MongoDB shell version: 2.6.4