源：
不带：同步 目录和内容
带/： 只同步内容
target目录：
待。
-Warv --delete
-W, --whole-file copy files whole (without delta-xfer algorithm)
-a, --archive archive mode; equals -rlptgoD (no -H,-A,-X)
-r, --recursive recurse into directories
-v, --verbose increase verbosity
--delete delete extraneous files from destination dirs
http://blog.csdn.net/moqiang02/article/details/37938059
http://qdosmsq.dunbar-it.co.uk/blog/2013/02/rsync-to-slash-or-not-to-slash/