This is what I used to kill the progress on port 4200
For linux users:
sudo kill $(sudo lsof -t -i:4200)
You could also try this:
sudo kill `sudo lsof -t -i:4200`
For windows users:
Port number 4200 is already in use. Open the cmd as administrator. Type below command in cmd:
netstat -a -n -o
And then, find port with port number 4200 by right click on terminal and click find, enter 4200 in “find what” and click “find next”:
Let say you found that port number 4200 is used by pid 18932. Type below command in cmd:
taskkill -f /pid 18932
For UNIX:
alias ngf="kill -9 $(lsof -t -i:4200);ng serve"
Now run ngf (instead of ng serve) in terminal from the project folder. This will kill all processes using the port 4200 and runs your Angular project.