using System;
using System.Text.RegularExpressions;
 
namespace RegExApplication
{
   public class Program
   {
      public static void Main(string[] args)
      {
         string input = "atext[d][][ef]\nother[aa][][a]\nxxxxx[][xx][x][][xx]\nyyyyy[]";
         string pattern = "(?m).*(\\[.*\\])";
         Regex rgx = new Regex(pattern);
 
         Match match = rgx.Match(input);
 
        	while (match.Success)
        	{
            	Console.WriteLine(match.Groups[1].Value);
            	match = match.NextMatch();
        	}
      }
   }
}