Re: Rmail tips

[Ben Hancock]

[Ben wrote:]
>> When a message is "unseen", the dash at position 6 (zero-indexed)
>> gets a special "U" flag, changing the header to this:
>>
>>     X--RMAIL-ATTRIBUTES: ------U-
>>
>> Rmail treats these messages differently; it will default to opening
>> the first unseen message when reading a file into rmail, and unseen
>> messages get a different face in the summary buffer so they stand
>> out.

[Colin replied:]
> I never knew that. I get the X-RMAIL-ATTRIBUTES header but not the `U'
> on messages that are definitely unseen. Is there some variable that
> must be set to actually see these attributes?

I don't think so; from what I can tell, the U flag is set on messages
that Rmail retrieves out of what it calls the "inbox" - either a system
mailbox, or a remote mailbox. See (info "(emacs) Rmail Inbox").

In rmail.el, it looks like this process calls a function named
rmail-add-mbox-headers that sets the U flag. It sounds like you're using
procmail to put new mail into your rmail-file-name directly, so that
step doesn't happen.

You may be able to use procmail to add the header as messages to come
in, perhaps in combination with formail. I don't use either, but based
on docs it seems possible:

  https://linux.die.net/man/1/formail

Best,
Ben