BASH

Check for Open Ports and Kill Processes

Learn how to use a bash script to check if a specific port is in use and, if desired, automatically identify and terminate the process occupying that port.

#!/bin/bash

PORT=$1

if [ -z "$PORT" ]; then
  echo "Usage: $0 <port_number>"
  exit 1
fi

PID=$(lsof -t -i:$PORT)

if [ -z "$PID" ]; then
  echo "Port $PORT is free."
else
  echo "Port $PORT is occupied by PID $PID."
  read -p "Do you want to kill this process? (y/N): " choice
  if [[ "$choice" =~ ^[Yy]$ ]]; then
    kill -9 "$PID"
    echo "Process $PID killed."
  else
    echo "Process not killed."
  fi
fi

How it works: This script takes a port number as an argument, uses `lsof` to determine if that port is in use, and identifies the process ID (PID) occupying it. If the port is busy, it prompts the user to confirm whether they want to terminate the process. This is particularly useful for web developers who often encounter "Address already in use" errors when starting local servers.

Check for Open Ports and Kill Processes

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