Use n module from npm in order to upgrade node
sudo npm cache clean -f
sudo npm install -g n
sudo n stable
sudo ln -sf /usr/local/n/versions/node/<VERSION>/bin/node /usr/bin/node
To upgrade to latest version (and not current stable) version, you can use
sudo n latest
To undo:
sudo apt-get install --reinstall nodejs-legacy # fix /usr/bin/node
sudo n rm 6.0.0 # replace number with version of Node that was installed
sudo npm uninstall -g n
