npm not found ubuntu 18.04 code example
Example 1: ubuntu 18 install nodejs
cd ~
curl -sL https://deb.nodesource.com/setup_12.x -o nodesource_setup.sh
sudo bash nodesource_setup.sh
sudo apt install nodejs
nodejs -v # shows your version
Example 2: install nodejs from ubuntu 18.04
sudo bash nodesource_setup.sh