Sets the default for determining whether the SEND, REPLY, or
    FORWARD commands return to the sender a copy of the message being
    sent.
    By specifying the NOSEND, NOREPLY, or NOFORWARD keywords with the
    SET COPY_SELF command, you can clear any default copying you have
    established with the SET COPY_SELF command.
    The SHOW COPY_SELF command displays which commands (SEND, REPLY,
    or FORWARD) automatically send a copy of the message to you.
    Format
      SET COPY_SELF  command [,command]
      SHOW COPY_SELF
Additional Information:
explode
extract