This is an implementation of File Transfer Protocol (FTP), using the protocol stack TCP/IPv4 for the user interface to the standard FTP. The server program is a concurrent server which handle multiple clients simultaneously. The FTP prompt with wait for next command until "bye" command is given. Following commands are recognized by this FTP program:

• bye
  Terminate the FTP session with the remote server and exit FTP. An EOF will also terminate the session and exit.
  
  
• cd (remote-directory)
  Change the working directory on the remote machine to remote directory.
  
  
• cdup
  Change the remote machine working directory to the parent of the current remote machine working directory.
  
  
• close
  Terminate the FTP session with the remote server and return to the command interpreter.
  
  
• disconnect
  A synonym for close.
  
  
• help [ command ]
  Print an informative message about the meaning of command. If no argument is given, FTP prints a list of the known commands.
  
  
• lcd [ directory ]
  Change the working directory on the local machine. If no directory is specified, the user’s home directory is used.
  
  
• open host [port]
  Establish a connection to the specified host FTP server. An optional port number may be supplied, in which case, FTP will attempt to contact an FTP server at that port.
  
  
• pwd
  Print the name of the current working directory on the remote machine.
  
  
• quit
  A synonym for bye.
  
  
• ? [ command ]
  A synonym for help.