using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        string pattern = @"^\[\w+]\s.+$";

        string text= "[Keys]\nW, A, S, D";

        TestMatch(pattern, text);

        text = "[Cat]\nBrown, Black, white";

        TestMatch(pattern, text);

        text = "[Uh_Oh_Spaghettios]\nThis is some text, Same, So is this";

        TestMatch(pattern, text);

        Console.WriteLine("Done");

    }

    private static void TestMatch(string pattern, string text){

        Console.WriteLine("Testing text...");

        var match = Regex.Match(text, pattern);

        if (match.Success)

         Console.WriteLine(match);

      else

         Console.WriteLine("Nope :(");

    }

}