The watch flag tells Sass to watch your source files for changes, and re-compile CSS each time you save your Sass.
To watch individual file changes, you'd just add the watch flag to your command, like so:
Note: Any changes that are saved in basic.scss will affect basic.css file by the following command.
To watch file changes inside individual folder, you'd just add the watch flag to your command, like so:
Note: Any changes to any file under the scss folder that is saved will affect the css folder by the following command.