using System;
using System.Text.RegularExpressions;
 
namespace RegExApplication
{
   public class Program
   {
      public static void Main(string[] args)
      {
         string input = "-user 'username' -locale 'us' -pwd 'realpwd' -time 'pst' ";
         string pattern = "(-pwd +)\'(?:.*?)\'";
         Regex rgx = new Regex(pattern);
         string result = rgx.Replace(input, "$1\'****\'");
 
         Console.WriteLine("Original String: {0}", input);
         Console.WriteLine("Replacement String: {0}", result);    
         Console.ReadKey();
      }
   }
}

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