rsync

经典的备份命令:

$ rsync -av -r -d --delete SRC DEST

--archive, -a:

Archive mode

--verbose, -v:

Increase verbosity

--recursive, -r:

Recurse into directories

--dirs, -d:

Transfer directories without recursing

--delete:

Delete extraneous files from dest dirs

关于 -r 和 -d 的区别，rsync(1) 如是说：

Tell the sending side to include any directories that are encountered. Unlike --recursive, a directory's contents are not copied unless the directory name specified is "." or ends with a trailing slash (e.g. ".", "dir/.", "dir/", etc.). Without this option or the --recursive option, rsync will skip all directories it encounters (and output a message to that effect for each one). If you specify both --dirs and --recursive, --recursive takes precedence.

并没有看懂……

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