rsync非常強大，下面是我用rsync做目錄備份時用到的參數：

rsync -ruPi -plEt /home/op/photo/ /remote_backup/photo/ --dry-run

-r 循環目錄
-u update模式，只同步更新過的
-P 等於--partial --progress，顯示進度，並支持斷點續傳
-i 顯示每個文件的同步細節，見下面--itemize-changes部分

-p 保留權限
-l 拷貝軟鏈接（如果要拷貝鏈接指向的實際文件，用-L）
-E 保留執行權限
-t 保留修改時間
--delete 同步刪除動作

其中，-i 顯示每個文件的同步細節，見下面--itemize-changes部分
下面內容轉自：stackoverflow

Explanation of each bit position and value in rsync‘s output:

YXcstpoguax  path/to/file
|||||||||||
||||||||||╰- x: The extended attribute information changed
|||||||||╰-- a: The ACL information changed
||||||||╰--- u: The u slot is reserved for future use
|||||||╰---- g: Group is different
||||||╰----- o: Owner is different
|||||╰------ p: Permission are different
||||╰------- t: Modification time is different
|||╰-------- s: Size is different
||╰--------- c: Different checksum (for regular files), or
||              changed value (for symlinks, devices, and special files)
|╰---------- the file type:
|            f: for a file,
|            d: for a directory,
|            L: for a symlink,
|            D: for a device,
|            S: for a special file (e.g. named sockets and fifos)
╰----------- the type of update being done::
             <: file is being transferred to the remote host (sent)
             >: file is being transferred to the local host (received)
             c: local change/creation for the item, such as:
                - the creation of a directory
                - the changing of a symlink,
                - etc.
             h: the item is a hard link to another item (requires 
                --hard-links).
             .: the item is not being updated (though it might have
                attributes that are being modified)
             *: means that the rest of the itemized-output area contains
                a message (e.g. "deleting")
 

Some example output from rsync for various scenarios:

>f+++++++++ some/dir/new-file.txt
.f....og..x some/dir/existing-file-with-changed-owner-and-group.txt
.f........x some/dir/existing-file-with-changed-unnamed-attribute.txt
>f...p....x some/dir/existing-file-with-changed-permissions.txt
>f..t..g..x some/dir/existing-file-with-changed-time-and-group.txt
>f.s......x some/dir/existing-file-with-changed-size.txt
>f.st.....x some/dir/existing-file-with-changed-size-and-time-stamp.txt 
cd+++++++++ some/dir/new-directory/
.d....og... some/dir/existing-directory-with-changed-owner-and-group/
.d..t...... some/dir/existing-directory-with-different-time-stamp/
 

rsync增量同步標誌位詳細解釋