$ npm install --global strip-css-comments-cli

$ strip-css-comments --help

  Usage
    $ strip-css-comments <input-file> > <output-file>
    $ strip-css-comments < <input-string>

  Options
    --preserve=<regex>  Preserve comments matching a regex [Default: ^!]
    --no-preserve       Strip all comments including `/*!`

  Examples
    $ strip-css-comments src/app.css > dist/app.css
    $ strip-css-comments < src/app.css --preserve='^#'