DiffMatchPatch command line

DiffMatchPatchProgram.cs

/* to build: 
 *  download DiffMatchPatch from http://code.google.com/p/google-diff-match-patch/
 *  then in command line run
 *  "%WINDIR%\Microsoft.NET\Framework\v3.5\csc.exe" /out:DiffMatchPatch.exe DiffMatchPatch.cs DiffMatchPatchProgram.cs
 *  
 * to create patch:
 *  DiffMatchPatch.exe file1 file2 destination
 * to apply patch
 *  DiffMatchPatch.exe patch file_to_patch
 */

namespace DiffMatchPatch
{
    using System;
    using System.IO;

    class Program
    {
        public static int Main(string[] args)
        {
            if (!(args.Length == 3 || args.Length == 2))
            {
                Console.WriteLine("usage: to create patch => DiffMatchPatch.exe file1 file2 destination");
                Console.WriteLine("       to apply patch  => DiffMatchPatch.exe patch file_to_patch");
                return 1;
            }

            if (args.Length == 3)
                return CreatePatch(args);
            else
                return ApplyPatch(args);
        }

        public static int CreatePatch(string[] args)
        {
            string text1 = GetFileContents(args[0]);
            string text2 = GetFileContents(args[1]);

            var diffMatchPatch = new diff_match_patch();
            var patches = diffMatchPatch.patch_make(text1, text2);

            WriteFile(args[2], diffMatchPatch.patch_toText(patches));

            return 0;
        }

        public static int ApplyPatch(string[] args)
        {
            var patchText = GetFileContents(args[0]);
            var fileToPatch = GetFileContents(args[1]);

            var diffMatchPatch = new diff_match_patch();
            var patches = diffMatchPatch.patch_fromText(patchText);

            var result = diffMatchPatch.patch_apply(patches, fileToPatch);
            var boolResult = (bool[])result[1];
            foreach (var r in boolResult)
            {
                if (!r)
                {
                    Console.WriteLine("Applying patch failed");
                    return 1;
                }
            }

            File.Delete(args[1]);
            WriteFile(args[1], result[0].ToString());
            return 0;
        }

        private static string GetFileContents(string path)
        {
            if (!File.Exists(path))
            {
                Console.WriteLine(path + " doesn't exisit");
                Environment.Exit(1);
            }

            using (var fs = File.OpenText(path))
            {
                return fs.ReadToEnd();
            }
        }

        private static void WriteFile(string path, string content)
        {
            if (File.Exists(path))
            {
                Console.WriteLine("file already exists");
                Environment.Exit(1);
            }

            File.WriteAllText(path, content);
        }

    }
}