using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var input = "portname (some_code_here!=)";

        var unlocode = GetUnlocode(input);

        Console.WriteLine(unlocode);

    }

    public static string GetUnlocode(string portName)

    {

        var pattern = @"\((?<unlocode>[\w\W]+)\)";      

        var regex = new Regex(pattern);

        var match = regex.Match(portName);

        if(match.Success) return match.Groups["unlocode"].Value;    

        return string.Empty;

    }

}