nmh (and MH) do not currently lock the .mh_sequences file. That's why
many people (including myself) using the directory locking in procmail.
Except that if one is using "show" to look at messages, you can still
end up corrupting your sequences file when both show and procmail try to
access it at the same time.
One way around this is to wrap 'show' with a shell script that uses
'lockfile' for procmail-style locking. Is there a better way?
-- Lars
--
Lars Kellogg-Stedman * lars(_at_)bu(_dot_)edu * (617)353-8277
Office of Information Technology, Boston University