Something is already running on port 3000. code example

Example 1: how to close port 3000 running

### For Linux/Mac OS search (sudo) run this in the terminal:
$ lsof -i tcp:3000
$ kill -9 PID

### On Windows:
netstat -ano | findstr :3000
tskill typeyourPIDhere 

### change tskill for taskkill in git bash

Example 2: port 8080 already in use

netstat -ano | findstr 8080

Example 3: npm port already in use

$ lsof -i tcp:3000
$ kill -9 PID

Example 4: Port 3000 is already in use, but when I try to kill nothing is found

netstat -ano | findstr :3000
taskkill /PID "123" /F

Example 5: port 8080 already in use

taskkill /F /pid 1088

Example 6: stop npm running on port 3000

netstat -ano | findstr :3000
taskkill /F /PID PID_of_port