Woops! "disparate" is should be :blush: but maybe it goes to show you the state of mind I was in when I posted the thread :-D

Well, to answer some of my own questions :

1. MIME::Parser is way too heavy for this purpose. If you have to call $parser->filer->purge(); to delete all the files created from each of the mails. This really seems too much to "just read 4 fields from an email header".

MIME::Head however seems to fit the bill very well :

my $head = MIME::Head->read( \*FILE ); # TODO : Does it read the WHOLE
+ email or skips the remaining mail after reading the header?
$head->unfold;

# Was a "Subject:" field given?
# $subject_was_given = $head->count('subject');

print $head->get('subject');
print $head->get('Message-ID');
print $head->get('from');
print $head->get('date');
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2. I would appreciate some answers to this.

Of course missing id's will be logged and error handling done, but I was wondering if there are any servers with such known behaviour.

3. This works just dandy :

use Date::Manip;
Date_Init("ConvTZ=IGNORE","TZ=GMT");

my $date = UnixDate( $head->get('date') , '%Y_%m_%Q-%H%M%S');
print $date;
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This can convert, for eg : "Sat, 9 Feb 2008 17:04:08 EET" to "2008_02_20080209-170408"

Thanks guys for the great insights! Furthur tips/tricks/etc are welcome though.