fix help doc
fix help doc

daodaoliang/tcpcopy,horryq/tcpcopy,eliteYang/tcpcopy,eliteYang/tcpcopy,ycaihua/tcpcopy,wfxiang08/tcpcopy,ycaihua/tcpcopy,left2right/tcpcopy,u20024804/tcpcopy,liviusATnetskope/second,sshling/tcpcopy,liviusATnetskope/second,caosiyang/tcpcopy,caosiyang/tcpcopy,sshling/tcpcopy,u20024804/tcpcopy,wfxiang08/tcpcopy,horryq/tcpcopy,daodaoliang/tcpcopy,left2right/tcpcopy