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"Port 4200 is already in use" when running the ng serve command

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

  • 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.