Simple FTP Client and Server

To do on Server

  USER <SP> <username> <CRLF>
  PASS <SP> <password> <CRLF>
  ACCT <SP> <account-information> <CRLF>
  CWD <SP> <pathname> <CRLF>
  CDUP <CRLF>
  SMNT <SP> <pathname> <CRLF>
  QUIT <CRLF>
  REIN <CRLF>
  PORT <SP> <host-port> <CRLF>
  PASV <CRLF>
  TYPE <SP> <type-code> <CRLF>
  STRU <SP> <structure-code> <CRLF>
  MODE <SP> <mode-code> <CRLF>
  RETR <SP> <pathname> <CRLF>
  STOR <SP> <pathname> <CRLF>
  STOU <CRLF>
  APPE <SP> <pathname> <CRLF>
  ALLO <SP> <decimal-integer>
  [<SP> R <SP> <decimal-integer>] <CRLF>
  REST <SP> <marker> <CRLF>
  RNFR <SP> <pathname> <CRLF>
  RNTO <SP> <pathname> <CRLF>
  ABOR <CRLF>
  DELE <SP> <pathname> <CRLF>
  RMD <SP> <pathname> <CRLF>
  MKD <SP> <pathname> <CRLF>
  PWD <CRLF>
  LIST [<SP> <pathname>] <CRLF>
  NLST [<SP> <pathname>] <CRLF>
  SITE <SP> <string> <CRLF>
  SYST <CRLF>
  STAT [<SP> <pathname>] <CRLF>
  HELP [<SP> <string>] <CRLF>
  NOOP <CRLF>