On my machine, it shows the default node version that is v8.
To develop the Angular application, you must have installed the latest version of NodeJS ( > 10.13.0 ) and NPM (6.11.0).
Tp Upgrade to latest NodeJS in Ubuntu 18.04 , follow these step
sudo npm cache clean -f
sudo npm install -g n
sudo n stable
Still you want to latest version other than stable version, use this command
sudo n latest
After successful of the above commands, now you can check node -v command to verify the latest version. Now I have latest version of npm and nodeJS.
After this, AngularCLI got installed successfuly and able to create angular application.
