How to kill process that run on specific port in Windows,Linux and MacOS - C# (.Net Core)

Question

I need to kill process that uses port 8001 in Windows,Ubuntu and MacOS before starting my application via C# Code,because my application is need to use 8001 on all platform.

So Please Provide me Solution for this problem.

Answer 1

Windows

• Find process ID

  • command netstat -a -b
  • Resource monitor from (Start>>All Programs>>Accessories>>System Tools>>Resource Monitor)

• kill the process using the below command taskkill /PID pid

UNIX and MAC

• Find process ID using lsof -i | grep <process id>
• kill the process using the command kill -9 <process id>

Answer 2

Here is the code sample in C#

using System; <br>
using System.Diagnostics;  <br>
using System.Collections.Generic; <br>
using System.Text.RegularExpressions; <br>
namespace Solution
{
    public enum Platform
    {
        UNIX, WIN
    }

    public class ProcessUtils
    {

        public const string UNIX_PID_REGX = @"\w+\s+(\d+).*";
        public const string WIND_PID_REGX = @".*\s+(\d+)";

        public static void Main(string[] args) {
            Console.WriteLine("Hello World!");

            if (args !=  null && args.Length == 1) {
                findAndKillProcessRuningOn(port: args[0]);
            } else {
                Console.WriteLine("Illegal port option");
            }
        }

        public static void findAndKillProcessRuningOn(string port) {
            List<string> pidList = new List<string>();
            List<string> list = new List<string>();
            switch (getOSName())
            {
                case Platform.UNIX:
                    list = findUnixProcess();
                    list = filterProcessListBy(processList: list, filter: ":" + port);

                    foreach(string pidString in list) {
                        string pid = getPidFrom(pidString: pidString, pattern: UNIX_PID_REGX);

                        if(!String.IsNullOrEmpty(pid)) {
                            pidList.Add(pid);
                        }
                    }
                    break;

                case Platform.WIN:
                    list = findWindowsProcess();
                    list = filterProcessListBy(processList: list, filter: ":" + port);

                    foreach (string pidString in list)
                    {
                        string pid = getPidFrom(pidString: pidString, pattern: WIND_PID_REGX);

                        if (!String.IsNullOrEmpty(pid))
                        {
                            pidList.Add(pid);
                        }
                    }
                    break;
                default:
                    Console.WriteLine("No match found");
                    break;
            }

            foreach(string pid in pidList) {
                killProcesBy(pidString: pid);
            }
        }

        public static Platform getOSName() {
            string os = System.Environment.OSVersion.VersionString;
            Console.WriteLine("OS = {0}", os);

            if (os != null && os.ToLower().Contains("unix")) {
                Console.WriteLine("UNXI machine");
                return Platform.UNIX;
            } else {
                Console.WriteLine("Windows machine");
                return Platform.WIN;
            }
        }

        public static void killProcesBy(string pidString) {
            int pid = -1;
            if(pidString !=  null && int.TryParse(s: pidString, result: out pid)){
                Process p = Process.GetProcessById(pid);
                p.Kill();
                Console.WriteLine("Killed pid =" + pidString);
            } else {
                Console.WriteLine("Process not found for pid =" + pidString);
            }

        }

        public static List<String> findUnixProcess() {
            ProcessStartInfo processStart = new ProcessStartInfo();
            processStart.FileName = "bash";
            processStart.Arguments = "-c lsof -i";

            processStart.RedirectStandardOutput = true;
            processStart.UseShellExecute = false;
            processStart.CreateNoWindow = true;

            Process process = new Process();
            process.StartInfo = processStart;
            process.Start();

            String outstr  = process.StandardOutput.ReadToEnd();

            return splitByLineBreak(outstr);
        }

        public static List<String> findWindowsProcess()
        {
            ProcessStartInfo processStart = new ProcessStartInfo();
            processStart.FileName = "netstat.exe";
            processStart.Arguments = "-aon";

            processStart.RedirectStandardOutput = true;
            processStart.UseShellExecute = false;
            processStart.CreateNoWindow = true;

            Process process = new Process();
            process.StartInfo = processStart;
            process.Start();

            String outstr = process.StandardOutput.ReadToEnd();

            return splitByLineBreak(outstr);
        }

        public static List<string> splitByLineBreak(string processLines)
        {
            List<string> processList = new List<string>();

            if (processLines != null)
            {
                string[] list = processLines.Split(new[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
                processList.AddRange(collection: list);
            }

            return processList;
        }

        public static List<String> filterProcessListBy(List<String> processList, 
                                                   String filter) {

            if(processList == null) {
                return new List<string>();
            }

            if(filter == null) {
                return processList;
            }

            return processList.FindAll(i => i != null && i.ToLower().Contains(filter.ToLower()));
        }

        public static String getPidFrom(String pidString, String pattern) {
            MatchCollection matches = Regex.Matches(pidString, pattern);

            if(matches != null && matches.Count > 0) {
                return matches[0].Groups[1].Value;
            }

            return "";
        }
    }
}

Answer 3

For windows you can find any port is free or not -->

Check if port 8081 is free

•   netstat -ano | findstr :8081

If not free and want this for any job, then above will give you pid use that in below to kill old old using port 8081 –

•   taskkill /PID pid

For mac and Ubuntu follow - https://stackoverflow.com/a/57290177/17673102

Answer 4

Kill Each Process Manually

There are some great answers here already, mostly recommending the method of finding the process ID by using sudo lsof -i :<port number> to see the processes running on the specified port and then running kill -9 <process id> for each process id to kill them 1 by 1.

TLDR;

• sudo lsof -i :<port number> - list processes on port
• kill -9 <process id> - kill process by PID

The flaw in this method is that you must first determine the list of PIDs and then kill them each manually. This script will allow you to kill all processes running on a given port without ever having to look at the PIDs:

Script to Kill All Processes on Port

#!bin/zsh

# Example Usage: pkill 3000
# Kills all processes listening on the specified port
pkill () {
    sudo lsof -i :$1 | # get a list of all processes listening on the specified port
    xargs -I % echo % | # convert the list into a string
    awk '{print $2}' | # select only the PID column (2)
    awk 'NR%2==0' | # remove the header PID
    sort | # sort the PID list
    awk '!a[$0]++' | # remove duplicate PIDs
    xargs kill -9 # kill all the processes by their PIDs
}

Alternatively, you can just use the script run by the function, but I hope seeing the pkill function provides a useful explaination for what each of the piped commands does.

One Line Version

sudo lsof -i :$<process id> | xargs -I % echo % | awk '{print $2}' | awk 'NR%2==0' | sort | awk '!a[$0]++' | xargs kill -9

Answer 5

On macOS and Linux

This way you dont have to know the PID ;)

sudo kill -9 $(netstat -vanp tcp | grep 8001 | grep -v grep | awk '{print $9}')