using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

public class Test
{
	public static void Main()
	{
		var pattern = @"/(?<Command>\w+)(?:@(?<Target>\S+))?(?<Args>(?s).*)";
    	var text = "/ping@mybot arg1 arg2";
        var match = Regex.Match(text, pattern);
        if (match.Success)
        {
        	Console.WriteLine(match.Groups["Command"].Value);
        	Console.WriteLine(match.Groups["Target"].Value);
        	Console.WriteLine(match.Groups["Args"].Value);
        }
	}
}