how to stop the port which is already in use code example
Example 1: Port 4200 is already in use. Use '--port' to specify a different port
sudo lsof -t -i tcp:4200 | xargs kill -9
Example 2: how to close all ports angular
If you use 'Visual Studio Code' just click on the 'kill Terminal' on the top-right of the terminal and all the terminals ports will colsed