force to kill any process port ubuntu
sudo kill -9 $(sudo lsof -t -i:9001)
lsof   - list of files(Also used for to list related processes)
-t     - show only process ID
-i     - show only internet connections related process
:9001  - show only processes in this port number
kill   - command to kill the process
-9     - forcefully
sudo   - command to ask admin privilege(user id and password).