Sam, I am following your instruction on how to enable the mail arrival notification
function. But I still got some bugs.

I am using the MS Outlook to send test mails and if I compose one mail and send
it, everything is OK and I read everything from the STDIN_FILEFO and get env
Variables from. But when I forward one email or reply one email, I can read
nothing from the STDIN_FILENO and also | env >/usr/lib/courier/temp/env does not
work.

What is going on?

Contents of .courier ./test | /usr/local/bin/mail_arrival_notice | env > /usr/lib/courier/temp/env

Thank You and I am waiting for your reply!