KillNode Script For React Apps

TL;DR
This is a script to delete a running node process, if one exists.

#!/bin/bash

lsof_output=$(lsof -i :3000)

if [ -n "$lsof_output" ]; then
  node_line=$(echo "$lsof_output" | grep "node")

  if [ -n "$node_line" ]; then
    pid=$(echo "$node_line" | awk '{print $2}')

    # Kill the Node.js process with SIGKILL (9)
    echo "Killing Node.js process with PID $pid"
    kill -9 $pid

    echo "Node.js process killed."
  else
    echo "No Node.js process found on port 3000."
  fi
else
  echo "No process is listening on port 3000."
fi

It's very useful when running npm start to spin up a React app and you get a Port 3000 is already in use message.

You can also pair it with the npm start command right after it for a better experience. If the port is not in use the script will not do anything.

I went ahead and created an alias for even more convenience, and to do that follow these steps:

1. Open your .zshrc or .bashrc with: code ~/.zshrc
2. Add alias killnode="killnode.sh && npm start"
3. Run it from you app's folder

Enjoy 🦾