You build node.js app with express v4.x then start your app by npm start. My question is how to stop the app? Is there npm stop? EDIT to include the error when implement npm stop /home/nodetest2# npm stop > nodetest2@0.0.1 stop /home/nodetest2 > pkill -s SIGINT nodetest2 pkill: invalid argument for option 's' -- SIGINT npm ERR! nodetest2@0.0.1 stop: `pkill -s SIGINT nodetest2` npm ERR! Exit status