If you want real, raw scripting power, consider Win32::OLE together with Microsoft Outlook - it's quite some thing, and it is almost fully scriptable.

Mark Overmeer has written a Tk Perl mailclient, out of which many of his Mail::Box modules came, which will be of much use to you if you decide on embarking on writing your own mail client.

Personally, I have a Mail::Audit script in my .forward file, which processes all my incoming mail into different folders, which I then read through an IMAP4 client.

If you want to stay with only one machine and only have POP3 inboxes, I recommend using one of the POP3 client modules to download your mail, and then feed the mails to another Perl script which then sorts them into local storage and munges them to whatever you want. Most mail readers can read the mailbox format or something similar.

perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ;    # The  
$d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider
($c = $d->accept())->get_request(); $c->send_response( new   #in the
HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' #  web
[download]

You wonder what this has to do with Perl - well, the point is that I'm looking for a mail client that is powerful enough to be scripted in Perl. I want it to launch small Perl scripts after fetching mail or on my command, and I want them to manipulate what was downloaded so that I can play nice tricks with it.

One thing you must set out of your mind is that e-mail is simple. To anyone: handling e-mail correctly is a complicated tasks!! Nested multiparts, encodings, unicode... even correctly parsing a mail header containing addresses requires a few hundred lines of Perl. Of course, the sloppy job only needs one.

You have a choice between various sets of modules to script e-mail. For instance the MIME::Entity group, the Mail::Audit stuff, and my MailBox suite. They are all automated e-mail processors, not readers. IMO, the first two are easier to learn, because they are smaller, but leave more of the complications to the programmer. MailBox contains things like read(), forward(), bounce(), build(), rebuild(), and send() in one integrate library.

Nick Ing-Simmons has made tkmail, which is a mail reader, but I couldn't find it. There is a Mail::Procmail. In the near future, I will release a Mail::Box::Procmail, with a fully Perl-based configuration.

Regexes are 1st grade readers compared to Procmail's recipes.

If things get any worse, I'll have to ask you to stop helping me.

Sylpheed-claws can do what you're asking. Custom actions are trivial. It's trivial to make it pipe the message to stdin for your script to receive and suck the output from stdout for the results.