https://github.com/nodejs/node-v0.x-archive/wiki/Installing-Node.js-via-package-manager#debian-and-ubuntu-based-linux-distributions
Setup with Ubuntu
curl -sL https://deb.nodesource.com/setup_4.x | sudo -E bash -
Then install with Ubuntu:
sudo apt-get install --yes nodejs
If you get node: command not found chances are likely you need to link your binary:
sudo ln -s /usr/bin/nodejs /usr/bin/node