string data = @"
mouseDown(1)
key(""m"")
key(""o"")
key(""n"")
key(""k"")
key(""e"")
key(""y"")
key(""\n"")
mouseDown(1)
";

string pattern = @"
(?(^key)                  # if key startst the line, absorb all keystrokes
   ((?:key\(\x22)          # Match but don't capture key(''
    (?<Press>[^\x22]+)     # Named capture Press holds keystroke
    (?:\x22\)[\r\n]+)      # Get the rest including \r\n
   )+                      # One or more
  |
   (?<Mouse>[^\r\n]+))     # Not a key.
";


Console.WriteLine( Regex.Replace( data, pattern, delegate (Match m) 
            {
                if ( string.IsNullOrEmpty( m.Groups["Mouse"].Value ) == false )
                    return m.Groups["Mouse"].Value;

                var keys = from Capture cp in m.Groups["Press"].Captures
                           select cp.Value.ToString();

                return string.Format( "keyType({0}){1}", string.Join( string.Empty, keys.ToArray() ), Environment.NewLine );
            
            }, RegexOptions.IgnorePatternWhitespace | RegexOptions.Multiline));

/* Output
mouseDown(1)
keyType(monkey\n)
mouseDown(1)

 */

            string lineRe = @"^[^\r\n]*[\r\n]+";
            string re = @"[^\x09\x0A\x0D\x20-\xD7FF\xE000-\xFFFD\x10000-x10FFFF]";
            string test = @"This is a test
this is also a test
here is a special character " + "\x06" + @"
and this is another " + "\x08" + @" in the line
";
            string testresult = "";
            StringBuilder tmp = new StringBuilder();

            bool gotOne = false;
            using (TextWriter tr = File.AppendText(@"c:\Users\Les\log.txt"))
            {
                foreach (Match mx in Regex.Matches(test, lineRe, RegexOptions.Multiline))
                {
                    gotOne = false;
                    string lineresult = Regex.Replace(mx.Value, re, delegate(Match mx2)
                    {
                        if (gotOne == false)
                        {
                            gotOne = true;
                            tr.Write("{0} {1}: {2}", DateTime.Now.ToLongDateString(), DateTime.Now.ToLongTimeString(), mx.Value);
                        }
                        return "";
                    });
                    tmp.Append(lineresult);
                }
            }
            testresult = tmp.ToString();
            Console.Write("{0}", testresult);
        }