NamedPipesHelloWorld.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Pipes;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace NamedPipes
{
    internal class Program
    {
        // usage: dotnet run -c Release server $pipeName
        //        dotnet run -c Release client $pipeName
        static async Task Main(string[] args)
        {
            string pipeName = args[1];
            CancellationTokenSource timeout = new (TimeSpan.FromSeconds(10));

            if (args[0] == "server")
            {
                using NamedPipeServerStream server = new (pipeName, PipeDirection.In, maxNumberOfServerInstances: 1, PipeTransmissionMode.Byte, PipeOptions.Asynchronous);

                Console.WriteLine("Server waiting for client to connect");
                await server.WaitForConnectionAsync(timeout.Token);
                Console.WriteLine("Server established a connection!");

                using StreamReader streamReader = new StreamReader(server, Encoding.UTF8);
                string line = null;
                while ((line = await streamReader.ReadLineAsync()) != null)
                {
                    Console.WriteLine(line);
                }
                Console.WriteLine("EOF!");
            }
            else
            {
                using NamedPipeClientStream client = new (".", pipeName, PipeDirection.Out, PipeOptions.Asynchronous);

                Console.WriteLine("Client waiting to connect to a server");
                await client.ConnectAsync(timeout.Token);
                Console.WriteLine("Client connected!");

                await client.WriteAsync(Encoding.UTF8.GetBytes($"Line 1 {Environment.NewLine}"), timeout.Token);
                await client.WriteAsync(Encoding.UTF8.GetBytes($"Line 2"), timeout.Token);
                await client.WriteAsync(Encoding.UTF8.GetBytes($" still line 2 {Environment.NewLine}"), timeout.Token);
                await client.WriteAsync(Encoding.UTF8.GetBytes($"Line 3 {Environment.NewLine}"), timeout.Token);
            }
        }
    }
}