文件夹同步工具，主要功能是在操作系统层面上，监视文件系统，当文件发生变化（更改、删除或者新增）时，进行提示，自动同步。-Folder synchronization tool, the main function of the level of the operating system, monitor file system when the file changes (change, delete or add), prompts, automatic synchronization.