This is a cron-based (1 second interval) scraper that checks the youtube subscribers count for a specific channel. The output can be a graph using asciichart or plain console.logs. You can take a look at index.js and choose the one you prefer.
Change the default PewDiePie channel in index.js to the one you want to observe and you are good to go.
npm install # or yarn
node index.js