write(1)              UNIX System V(Essential Utilities)               write(1)


NAME
      write - write to another user

SYNOPSIS
      write user [line]

DESCRIPTION
      write copies lines from your terminal to that of another user.  When
      first called, it sends the message:

            Message from yourname (tty??)  [ date ]...

      to the person you want to talk to.  When it has successfully completed
      the connection, it also sends two bells to your own terminal to indicate
      that what you are typing is being sent.

      The recipient of the message should write back at this point.
      Communication continues until an end of file is read from the terminal,
      an interrupt is sent, or the recipient has executed "mesg n".  At that
      point write writes EOT on the other terminal and exits.

      If you want to write to a user who is logged in more than once, the line
      argument may be used to indicate which line or terminal to send to (e.g.,
      term/12); otherwise, the first writable instance of the user found in
      /var/adm/utmp is assumed and the following message posted:

            user is logged on more than one place.
            You are connected to "terminal".
            Other locations are:
            terminal

      Permission to write may be denied or granted by use of the mesg command.
      Writing to others is normally allowed by default.  Certain commands, such
      as the pr command, disallow messages in order to prevent interference
      with their output.  However, if the user has super-user permissions,
      messages can be forced onto a write-inhibited terminal.

      If the character ! is found at the beginning of a line, write calls the
      shell to execute the rest of the line as a command.

      write runs setgid() [see setuid(2)] to the group ID tty, in order to have
      write permissions on other user's terminals.

      write will detect non-printable characters before sending them to the
      user's terminal.  Control characters will appear as a `^' followed by the
      appropriate ASCII character; characters with the high-order bit set will
      appear in meta notation. For example, `\003' is displayed as `^C' and
      `\372' as `M-z'.

      The following protocol is suggested for using write:  when you first
      write to another user, wait for them to write back before starting to
      send.  Each person should end a message with a distinctive signal (i.e.,


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write(1)              UNIX System V(Essential Utilities)               write(1)


      (o) for ``over'') so that the other person knows when to reply.  The
      signal (oo) (for ``over and out'') is suggested when conversation is to
      be terminated.

FILES
      /var/adm/utmp
                to find user
      /usr/bin/sh
                to execute !

SEE ALSO
      mail(1), mesg(1), pr(1), sh(1), who(1), setuid(2).

DIAGNOSTICS
      user is not logged on                  if the person you
                                             are trying to write
                                             to is not logged on.
      Permission denied                      if the person you
                                             are trying to write
                                             to denies that
                                             permission (with
                                             mesg).
      Warning: cannot respond, set mesg -y   if your terminal is
                                             set to mesg n and
                                             the recipient cannot
                                             respond to you.
      Can no longer write to user            if the recipient has
                                             denied permission
                                             (mesg n) after you
                                             had started writing.
























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