A few rough usage notes:
- npm install module : download and install module. Saves dependency in node_modules by default
- npm install module –save : saves module info in package.json
- npm install module -g : downloads and installs module globally, not just in the current dir/project, so can be reused by all projects
- npm init : creates a new package.json from answers to a few questions, plus any existing downloaded modules in node_modules (useful to recreate package.json if you didn’t install modules with –save initially)