Install nodejs or node.js on ubuntu

To install node.js ( nodejs ) on ubuntu, Run following commands.

# sudo add-apt-repository ppa:chris-lea/node.js

# sudo apt-get update

# sudo apt-get install nodejs

# sudo apt-get install software-properties-common

Install Packages using npm on Ubuntu
First install npm on ubuntu

# sudo apt-get install npm

Now install packages using npm
Install mongodb :

# npm install mongodb

Install express :

# npm install express