对于参数的详细的解释
cmds_allowed=ABOR,ACCT,APPE,CWD,CDUP,DELE,HELP,LIST,MODE,MDTM,MKD,NOOP,NLST,PASS,PASV,PORT,PWD,QUIT,REIN,RETR,RMD,RNFR,RNTO,SITE,SIZE,STOR,STAT,STOU,STRU,SYST,TYPE,USER
# ABOR - abort a file transfer 取消文件传输
# ACCT* - send account information 发送帐户信息
# APPE - append to a remote file 附加到远程文件
# AUTH - 权限
# CDUP - CWD to the parent of the current directory CWD到当前目录的父
# CWD - change working directory 更改目录
# DELE - delete a remote file 删除文件
# EPRT -
# EPSV -
# PEAT -
# HELP - return help on using the server 帮助使用服务器
# LANG -
# LIST - list remote files 列目录
# MD5 -
# MDTM - return the modification time of a file 返回文件的更新时间
# MFMT -
# MKD - make a remote directory 新建文件夹
# MLSD -
# MLST -
# MODE - set transfer mode 设置传输模式
# MODE -
# NLST - name list of remote directory 远程目录的名称列表
# NOOP - do nothing 什么都不做
# OPTS -
# PASS - send password 发送密码
# PASV - enter passive mode 进入被动模式
# PBSZ -
# PORT - open a data port 打开一个传输端口
# PROT -
# PWD - print working directory 显示当前工作目录
# QUIT - terminate the connection 退出
# REIN* - reinitialize the connection 重新初始化连接
# REST -
# RETR - retrieve a remote file 下载文件
# RMD - remove a remote directory 删除目录
# RNFR - rename from 重命名
# RNTO - rename to 重命名
# SITE - site-specific commands 特定于站点的命令
# SIZE - return the size of a file 返回文件大小
# STAT - return server status 服务器状态
# STOR - store a file on the remote host 上传文件
# STOU - store a file uniquely 唯一地存储文件
# STRU - set file transfer structure 设置文件传输格式
# STRU -
# SYST - return system type
# TYPE - set transfer type 设置传输类型
# USER - send username