-r
--recursive
Turn on recursive retrieving.
-l depth
--level=depth
Specify recursion maximum depth level depth. The default maximum depth is 5.
如果你不想错过subdirs,最好使用镜像选项-m:
-m
--mirror
Turn on options suitable for mirroring. This option turns on recursion and time-stamping, sets infinite
recursion depth and keeps FTP directory listings. It is currently equivalent to -r -N -l inf
--no-remove-listing.