The R Command
.............

master: `R FROM TO USER -OPTIONS SIZE'
     The `R' and the `-' are literal characters.  This is a request by
     the master to receive a file from the slave.  I do not know how
     SVR4 UUCP or QFT implement file transfer restart in this case.

    FROM
          This is the name of the file on the slave which the master
          wishes to receive.  It must not be in the spool directory,
          and it may not contain any wildcards.

    TO
          This is the name of the file to create on the master.  I do
          not believe that it can be a directory.  It may only be in
          the spool directory if this file is being requested to
          support an execution either on the master or on some system
          other than the slave.

    USER
          The name of the user who requested the transfer.

    OPTIONS
          A list of options to control the transfer.  The following
          options are defined (all options are single characters):
         `d'
               The master should create directories as necessary (this
               is the default).

         `f'
               The master should not create directories if necessary,
               but should fail the transfer instead.

         `m'
               The master should send mail to USER when the transfer is
               complete.

    SIZE
          This only appears if Taylor UUCP size negotiation is being
          used.  It specifies the largest file which the master is
          prepared to accept (when using SVR4 UUCP or QFT, this was
          specified in the `-U' option during the initial handshake).

     The slave then responds with an `R' command response.  UUPlus does
     not support `R' requests, and always responds with `RN2'.

    `RY MODE [SIZE]'
          The slave is willing to send the file, and file transfer
          begins.  The MODE argument is the octal mode of the file on
          the slave.  The master treats this just as the slave does the
          MODE argument in the send command, q.v.  I am told that SVR4
          UUCP sends a trailing SIZE argument.  For some versions of
          BSD UUCP, the MODE argument may have a trailing `M' character
          (e.g., `RY 0666M').  This means that the slave wishes to
          become the master.

    `RN2'
          The slave is not willing to send the file, either because it
          is not permitted or because the file does not exist.  This
          implies that the file request will never succeed.

    `RN6'
          This is only used by Taylor UUCP size negotiation.  It means
          that the file is too large to send, either because of the
          size limit specifies by the master or because the slave
          considers it too large.  The file transfer might succeed
          later, or it might not (this may be cleared up in a later
          release of Taylor UUCP).

    `RN9'
          This is only used by Taylor UUCP (versions 1.05 and up) and
          FSUUCP (versions 1.5 and up).  It means that the remote
          system was unable to open another channel (see the discussion
          of the `i' protocol for more information about channels).
          This implies that the file transfer might succeed later.

     If the slave responds with `RY', a file transfer begins.  When the
     file transfer is complete, the master sends a `C' command.  The
     slave pretty much ignores this, although it may log it.

    `CY'
          The file transfer was successful.

    `CN5'
          The temporary file could not be moved into the final location.

     After the `C' command response has been sent (in the `RY' case) or
     immediately (in an `RN' case) the master will send another command.