#First run this, to get port information (with the port you want to kill)
sudo lsof -i :3000
#Then run this, with <PID> replaced by the value in the column returned by previous command.
kill -9 <PID>sudo lsof -i :3000
kill -9 <PID>sudo lsof -i :3000
kill -9 PIDsudo lsof -i tcp:3000
npx kill-port 8080lsof -n -i TCP:8080
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
node 54762 user 23u IPv4 XXXXXXXXX 0t0 TCP 127.0.0.1:http-alt (LISTEN)
PID // is second field in the response . Then, kill that process:
kill -9 54762 // here put PID number found on the table 54762