In the callout about good names, I've fixed some typos. I also streamlined the language (removed some unneeded adverbs, phrasing) in that section.
In the "Key Points", there was reference to rmdir, which has been removed from the lesson, so I removed that key point.
fix grammar and rephrase repeated words
removed unneeded adverbs/words
remove reference to rmdir from key points; it is no longer in lesson