To change all .scss files into .sass files inside the current folder use the following code.
sass-convert --recursive --from scss --to sass --indent 't' .
--recursive: All files within the “current folder” and any folders inside the “current folder”
--from: Current file extension (e.g. scss)
--to: Desired file extension (e.g. sass)
--indent: Indentation Style (optional) ‘t’ means tab
The dot at the end means “current folder”
See the documentation and installation instructions for sass-convert here: https://www.npmjs.com/package/sass-convert