For Opening URLs from Terminal in Mac, Linux and Windows. Got it from This File.

# Mac
$ open <url>

#Linux
$ xdg-open <url>

# Windows
$ rundll32 url.dll,FileProtocolHandler <url>

In [[Go]] this is

switch runtime.GOOS {
	case "linux":
		err = execCommand("xdg-open", url).Start()
	case "windows":
		err = execCommand("rundll32", "url.dll,FileProtocolHandler", url).Start()
	case "darwin":
		err = execCommand("open", url).Start()
	default:
		err = fmt.Errorf("unsupported platform")
}