how to let fetchmail's output shown in minibar?

[anhnmncb]

Hi, list,
I have these lines in .gnus
(setq mail-sources
      '((file :path "/var/mail/anhnmncb"
              :prescript "fetchmail")))
When gnus rechieves mail, the fetchmail's output doesn't show anywhere,
I can't know what status it's in, how to configure to let fetchmail's
output echo into minibuffer?
-- 
Regards,

  anhnmncb
 gpg key: 44A31344