Qmail系统下实现删除定期不使用的帐户

vdeloldusers: usage: [options]
options: -a age_in_days (will delete accounts older than this date)
(default is 6 months or 180 days)
-v (print version number and exit)
-d [domain] (process only [domain])
-e (process every domain)
-D (actually delete users. no users are deleted without this option)
-V (verbose -- print old users that will be deleted)