public static boolean launchShell(String cmd,
    File dir) 
{
        try {
            Process p;
            if (dir != null)
                p = Runtime.getRuntime().exec("sh -s", null, dir);
            else
                p = Runtime.getRuntime().exec("sh -s");
            java.io.PrintStream in = new java.io.PrintStream(p.getOutputStream());
            in.println(cmd);
            in.flush();
            return true;
        }
        catch(java.io.IOException e) {
            e.printStackTrace();
            return false;
        }
}