rsync

rsync - a fast, versatile, remote (and local) file-copying tool

-a, --archive               archive mode; equals -rlptgoD (no -H,-A,-X)

-r, --recursive             recurse into directories

-v, --verbose               increase verbosity

--delete 　　　　This tells rsync to delete extraneous files from the receiving side. 如果目标目录有源目录中没有的文件，则会目标目录中对应的文件将会被删除