To run this:

• pip3 install -r requirements.txt

•   python youtube_comment_extractor.py --help
  
  Output:

  usage: youtube_comment_extractor.py [-h] [-l LIMIT] [-o OUTPUT] url
  
  Simple YouTube Comment extractor
  
  positional arguments:
  url                   The YouTube video full URL
  
  optional arguments:
  -h, --help            show this help message and exit
  -l LIMIT, --limit LIMIT
                          Number of maximum comments to extract, helpful for
                          longer videos
  -o OUTPUT, --output OUTPUT
                          Output JSON file, e.g data.json
  
• To download the latest 50 comments from https://www.youtube.com/watch?v=jNQXAC9IVRw and save them to data.json:

  python youtube_comment_extractor.py https://www.youtube.com/watch?v=jNQXAC9IVRw --limit 50 --output data.json