Node JS / NPM have become essential parts of many applications. Because of this, and my recent experience with Node, I have decided to compile some instructions on how to install Node JS/NPM so that you do not require the sudo command (I found I needed this constraint when using Ember-CLI).
Note: this tutorial was run on XUbuntu 14.04 (Ubuntu) & OSx Mavericks
There are many valid ways to install Node and NPM, so if you know of a different method that works for you by all means, stick with that. This tutorial on installing Node/NPM