def cmd_help(param)
      send_response "214- The following commands are recognized."
      commands = COMMANDS
      str = ""
      commands.sort.each_slice(3) { |slice|
        str += "     " + slice.join("\t\t") + LBRK
      }
      send_response str, true
      send_response "214 End of list."
    end
def cmd_help(param)
      send_response "214- The following commands are recognized."
      commands = COMMANDS
      str = ""
      commands.sort.each_slice(3) { |slice|
        str += "     " + slice.join("\t\t") + LBRK
      }
      send_response str, true
      send_response "214 End of list."
    end
handle the HELP FTP command by sending a list of available commands.