附xdg-open manual部分信息： xdg-open opens a file or URL in the user's preferred application. If a URL is provided the URL will be opened in the user's preferred web browser. If a file is provided the file will be opened in the preferred application for files of that type. xdg-open supports file, ftp, http and https URLs. xdg-open is for use inside a desktop session only. It is not recommended to use xdg-open as root.
