-P port Specifies the port to connect to on the remote host. Note that this option is written with a capital ‘P’, because -p is already reserved for preserving the times and modes of the file in rcp(1). #-P指定远程服务器ssh服务的端口 如:ssh端口为61204
-l limit Limits the used bandwidth, specified in Kbit/s. -l 指定拷贝的速度限制 单位是ct/s 如:-l 40000 表示40000Kbit/s=40000/8KB=5MB的速度