I saw some tutorial where the command was:
npm install –save
What does the –save option mean?
Update npm 5:
As of npm 5.0.0, installed modules are added as a dependency by default, so the –save option is no longer needed. The other save options still exist and are listed in the documentation for npm install.
Original answer:
Before version 5, NPM simply installed a package under node_modules by default. When you were trying to install dependencies for your app/module, you would need to first install them, and then add them (along with the appropriate version number) to the dependencies section of your package.json.
The –save option instructed NPM to include the package inside of the dependencies section of your package.json automatically, thus saving you an additional step.
In addition, there are the complementary options –save-dev and –save-optional which save the package under devDependencies and optionalDependencies, respectively. This is useful when installing development-only packages, like grunt or your testing library.
