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

namespace SourceFileUtility
{
	class Program
	{
		static void Main(string[] args)
		{
			if (args.Length < 3)
				return;

			var file = args[0];
			var source = args[1];
			var replacement = args[2];

			var str = System.IO.File.ReadAllText(file);
			str = Regex.Replace(str, source, replacement, RegexOptions.Singleline | RegexOptions.IgnoreCase);
			System.IO.File.WriteAllText(file, str);
		}
	}
}