Mono.Unix.UnixSignal example app; see http://www.jprl.com/Blog/archive/development/mono/2008/Feb-08.html#comment-399526948

gistfile1.cs

using System;
using System.Threading;
using Mono.Unix;
using Mono.Unix.Native;

class Test {
	static void Main ()
	{
		StartHandler();
		Console.WriteLine("Press any key to exit...");
		Console.ReadLine();
	}

	static void StartHandler()
	{
		new Thread(TerminateHandler).Start();
	}

	static void TerminateHandler()
	{
		Console.WriteLine("Initializing Handler for SIGINT");
		UnixSignal signal = new UnixSignal(Signum.SIGINT);
		while(signal.WaitOne())
		{
			Console.WriteLine("Control-C Pressed!");
			break;
		}
		Console.WriteLine("handler Terminated");
	}
}

What about if I want to handle multiple instances of the same signal?