Using Maildir format, changing mailbox

[Cameron Simpson]

Just an aside...

On 05Jun2020 16:15, mutt-ml at mail.com <mutt-ml at mail.com> wrote:
>To explain: I have a number of different email accounts on a number of
>different servers, and I do that for a number of reasons, one being
>that my email is then effectively pre-filtered.

Separating work and personal email is well worth doning anyway, not just 
for the filtering.

I've a remark about your procmail...

>Work email goes to,
>say, someone at example.com, non-work email to somebody at example.org, and
>so on. I want that to be the case with my local email experience as
>well, so I've set up procmail to deliver into different directories
>depending on where the email comes from/to:
>
># work
>:0:
>* ^(From|Cc|To).*someone at example.com
>Work/
>
># play
>:0:
>* ^(From|Cc|To).*somebody at example.org
>Play/

Maybe I'm misreading your setup, but I presume you're fetching from 
different mailboxes here? Fetch from work, fetch from personal, etc? If 
so, I'd use distinct procmailrcs altogether - no reliance on the 
addresses in the headers (which are unreliable); instead process the 
work messages with one set of rules and personal by another, done by 
supplying a "work procmail" when fetching from work etc.

OTOH, if work and personal just forward to some common mail address then 
you're in split up the premixed stream, and back into rules of the form 
you're already using.

In my case, I pull from a work mailbox into a distinct spool, and 
process that spool as "from work" using the "work rules". Entirely 
distinct from the personal rules.

Now, as it happens, the work rules in my case go "take a copy to the 
work folder for cross referencing, then file the message in the common 
spool". Which then runs my common rules for a mixed stream just like 
yours.

But the initial file deduces work vs personal from the fetch source, not 
the header contents.

Cheers,
Cameron Simpson <cs at cskk.id.au>