Open file in default Mac browser

preview.go

func preview(fname string) error {
	const GOOS string = runtime.GOOS

	switch {
	case GOOS == "darwin":
		if err := exec.Command("open", fname).Start(); err != nil {
			return err
		}

	default:
		// Locate the firefox browser in the PATH
		browserPath, err := exec.LookPath("firefox")
		if err != nil {
			return err
		}

		// Open the file in the browser
		if err := exec.Command(browserPath, fname).Start(); err != nil {
			return err
		}
	}

	return nil
}