IMPORTANT use nvm to install everything or your permisions will be all sorts of messed up.
curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.11/install.sh | bash
export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh" # This loads nvm
command -v nvm
--> [output: ] --> nvm
nvm install node
nvm install NODE_VERSION_NUMBER
> ie. nvm install 8
nvm use node
nvm use NODE_VERSION_NUMBER
> ie. nvm use 8
node --version
npm -v