[Mimedefang] Mbox Format From Separator Origin

David F. Skoll dfs at roaringpenguin.com
Tue Dec 9 11:09:32 EST 2008

Kevin A. McGrail wrote:

> However, what's the origin of the From separator to begin with?

Ancient UNIX tradition?  From_ is an evil ugly hack that unfortunately
has persisted.

> My belief is that it is the local delivery system, for example
> procmail, that generates it.

It is, usually.

> How can I generate one from MD or, more towards my goal.  The leading 
> question in this is that some emails seem to get a From line that is 
> generated with local user information, and others get it with more 
> email-specific sender information.  I'm trying to figure out if the lack 
> of email-specific From information would indicate spam.  However, a 
> quick peruse of my own corpora and quarantined email doesn't help much.

The From_ line is typically:

   From $Sender Wkday Mon  Day HH:MM:SS YYYY

For example:

   From bob at example.com  Tue Jan  1 00:35:53 2008

The stupidly-formatted date again suggests the ancient origin of the

All you need to do is generate a From_ line (using POSIX::strftime or
the like to format the date) and then append INPUTMSG to your mbox



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