Recently I needed a regex to parse the command line. Something like this:

/param1="sfsdf  sdf sdfsdf  sdfsdf" /param2 =rstwertw /param3 = "rtwqert sdfas f"

I found a great regex on RegExLib by Richard Hauer for doing this. I made one minor tweak to allow whitespace between the name/value delimiter:

(?:\s*)(?<=[-|/])(?\w*)\s*[:|=]\s*("((?.*?)(?[\w]*))

Here it is in action:

string commandLineRegEx = 
    @"(?:\s*)(?<=[-|/])(?\w*)\s*[:|=]\s*(""((?.*?)(?[\w]*))";
Regex regex = new Regex(commandLineRegEx);

MatchCollection matches = regex.Matches(
    "/param1=\"sfsdf  sdf sdfsdf  sdfsdf\" /param2 =rstwertw /param3 = \"rtwqert sdfas f\"");

foreach (Match match in matches)
    Console.WriteLine("{0}={1}", 
        match.Groups["name"].Value, 
        match.Groups["value"].Value);

Console.ReadKey();