输入问号(?),回车,就可以查看可以使用的命令
ftp> ?
Commands may be abbreviated. Commands are:! cr mdir proxy send
$ delete mget sendport site
account debug mkdir put size
append dir mls pwd status
ascii disconnect mode quit struct
bell form modtime quote system
binary get mput recv sunique
bye glob newer reget tenex
case hash nmap rstatus trace
ccc help nlist rhelp type
cd idle ntrans rename user
cdup image open reset umask
chmod lcd passive restart verbose
clear ls private rmdir ?
close macdef prompt runique
cprotect mdelete protect safe
如果不清楚某个命令的功能,可以使用 help 命令来查看其功能描述, 如输入help ls 会返回
list contents of remote directory