[Solved] "Port 4200 is already in use" when running the ng serve command - Angular

Article Mohaimen Khalid

Problem:

I am learning angular 2 and for the first time I am using the angular CLI project to create a sandbox project.

I was able to run the command "ng serve" and it works great. I wanted to stop it from running so I ran "Control Z".

When I tried to run the "ng-serve" command again it gives me "Port 4200 is already in use."

I ran "PS" to get a list of the PID and killed the PID for the angular-cli and ran "ng-serve" again still it gives the same port in use error.


Solution:

For Windows Users:

At first, we have to check which port are running on system.

Step 1: Open your CMD as Administrator mode.

Step 2: Then find the PID of port 4200 with this command -

netstat -ano | findstr :4200

Then you can show like this -

- Red one is from "ng-serve" (127.0.0.1:4200) that LISTENING

Now we kill only port 4200

taskkill /PID 15940 /F

Now you can see – SUCCESS: The process will PID 15904 has terminated.

For Mac OS Users: 

sudo lsof -t -i tcp:4200 | xargs kill -9

Note: Remember you need to kill Angular's web server with Command+C

For Linux users: 
sudo kill $(sudo lsof -t -i:4200)


you can also use -

sudo kill `sudo lsof -t -i:4200`