invoking write from cron

[Tom Corsetti]

Hi, 
I'm trying to set up a script that runs from cron, checks files
and sends me a message when certain files change in size.  I have
the following code in the script that sends the message:
        echo "message to send" | write userid
When I invoke the script interactively, it works.  When run from
cron, I get no message.  Is this because the write command also
sends userid and ttyxx device along with the message?  Since processes
invoked from cron have no tty associated with them, could this be the
problem?  Any suggestions are welcome!  Thanks in advance!
                                             - Tom

-- 
  Tom Corsetti                 * * * *   internet - tomc at dftsrv.gsfc.nasa.gov
  NASA/Goddard Space Flt Ctr    * * *    decnet   - dftnic::tomc
  Greenbelt Maryland           * * * *   bitnet   - tomc at dftbit