How stop after running react-scripts start?

Add this in your package.json:

"stop": "taskkill -F -IM node.exe"

Hit your keyboard shortcut for stopping terminal commands (usually Ctrl+C or Ctrl+Q)

Or, if you don't have input access to the process, identify its PID and kill it :

On Windows :

C:\>Taskkill /PID <PID> /F

On Linux :

$>kill -SIGTERM <PID>