gnus: Expiring Mail
6.4.9 Expiring Mail
-------------------
Traditional mail readers have a tendency to remove mail articles when
you mark them as read, in some way. Gnus takes a fundamentally
different approach to mail reading.
Gnus basically considers mail just to be news that has been received
in a rather peculiar manner. It does not think that it has the power to
actually change the mail, or delete any mail messages. If you enter a
mail group, and mark articles as “read”, or kill them in some other
fashion, the mail articles will still exist on the system. I repeat:
Gnus will not delete your old, read mail. Unless you ask it to, of
course.
To make Gnus get rid of your unwanted mail, you have to mark the
articles as “expirable”. (With the default key bindings, this means
that you have to type ‘E’.) This does not mean that the articles will
disappear right away, however. In general, a mail article will be
deleted from your system if, 1) it is marked as expirable, AND 2) it is
more than one week old. If you do not mark an article as expirable, it
will remain on your system until hell freezes over. This bears
repeating one more time, with some spurious capitalizations: IF you do
NOT mark articles as EXPIRABLE, Gnus will NEVER delete those ARTICLES.
You do not have to mark articles as expirable by hand. Gnus provides
two features, called “auto-expire” and “total-expire”, that can help you
with this. In a nutshell, “auto-expire” means that Gnus hits ‘E’ for
you when you select an article. And “total-expire” means that Gnus
considers all articles as expirable that are read. So, in addition to
the articles marked ‘E’, also the articles marked ‘r’, ‘R’, ‘O’, ‘K’,
‘Y’ (and so on) are considered expirable. ‘gnus-auto-expirable-marks’
has the full list of these marks.
When should either auto-expire or total-expire be used? Most people
who are subscribed to mailing lists split each list into its own group
and then turn on auto-expire or total-expire for those groups. (
Splitting Mail, for more information on splitting each list into its
own group.)
Which one is better, auto-expire or total-expire? It’s not easy to
answer. Generally speaking, auto-expire is probably faster. Another
advantage of auto-expire is that you get more marks to work with: for
the articles that are supposed to stick around, you can still choose
between tick and dormant and read marks. But with total-expire, you
only have dormant and ticked to choose from. The advantage of
total-expire is that it works well with adaptive scoring (Adaptive
Scoring). Auto-expire works with normal scoring but not with adaptive
scoring.
Groups that match the regular expression
‘gnus-auto-expirable-newsgroups’ will have all articles that you read
marked as expirable automatically. All articles marked as expirable
have an ‘E’ in the first column in the summary buffer.
By default, if you have auto expiry switched on, Gnus will mark all
the articles you read as expirable, no matter if they were read or
unread before. To avoid having articles marked as read marked as
expirable automatically, you can put something like the following in
your ‘~/.gnus.el’ file:
(remove-hook 'gnus-mark-article-hook
'gnus-summary-mark-read-and-unread-as-read)
(add-hook 'gnus-mark-article-hook 'gnus-summary-mark-unread-as-read)
Note that making a group auto-expirable doesn’t mean that all read
articles are expired—only the articles marked as expirable will be
expired. Also note that using the ‘d’ command won’t make articles
expirable—only semi-automatic marking of articles as read will mark the
articles as expirable in auto-expirable groups.
Let’s say you subscribe to a couple of mailing lists, and you want
the articles you have read to disappear after a while:
(setq gnus-auto-expirable-newsgroups
"mail.nonsense-list\\|mail.nice-list")
Another way to have auto-expiry happen is to have the element
‘auto-expire’ in the group parameters of the group.
If you use adaptive scoring (Adaptive Scoring) and
auto-expiring, you’ll have problems. Auto-expiring and adaptive scoring
don’t really mix very well.
The ‘nnmail-expiry-wait’ variable supplies the default time an
expirable article has to live. Gnus starts counting days from when the
message _arrived_, not from when it was sent. The default is seven
days.
Gnus also supplies a function that lets you fine-tune how long
articles are to live, based on what group they are in. Let’s say you
want to have one month expiry period in the ‘mail.private’ group, a one
day expiry period in the ‘mail.junk’ group, and a six day expiry period
everywhere else:
(setq nnmail-expiry-wait-function
(lambda (group)
(cond ((string= group "mail.private")
31)
((string= group "mail.junk")
1)
((string= group "important")
'never)
(t
6))))
The group names this function is fed are “unadorned” group names—no
‘nnml:’ prefixes and the like.
The ‘nnmail-expiry-wait’ variable and ‘nnmail-expiry-wait-function’
function can either be a number (not necessarily an integer) or one of
the symbols ‘immediate’ or ‘never’.
You can also use the ‘expiry-wait’ group parameter to selectively
change the expiry period (Group Parameters).
The normal action taken when expiring articles is to delete them.
However, in some circumstances it might make more sense to move them to
other groups instead of deleting them. The variable
‘nnmail-expiry-target’ (and the ‘expiry-target’ group parameter)
controls this. The variable supplies a default value for all groups,
which can be overridden for specific groups by the group parameter.
default value is ‘delete’, but this can also be a string (which should
be the name of the group the message should be moved to), or a function
(which will be called in a buffer narrowed to the message in question,
and with the name of the group being moved from as its parameter) which
should return a target—either a group name or ‘delete’.
Here’s an example for specifying a group name:
(setq nnmail-expiry-target "nnml:expired")
Gnus provides a function ‘nnmail-fancy-expiry-target’ which will
expire mail to groups according to the variable
‘nnmail-fancy-expiry-targets’. Here’s an example:
(setq nnmail-expiry-target 'nnmail-fancy-expiry-target
nnmail-fancy-expiry-targets
'((to-from "boss" "nnfolder:Work")
("subject" "IMPORTANT" "nnfolder:IMPORTANT.%Y.%b")
("from" ".*" "nnfolder:Archive-%Y")))
With this setup, any mail that has ‘IMPORTANT’ in its Subject header
and was sent in the year ‘YYYY’ and month ‘MMM’, will get expired to the
group ‘nnfolder:IMPORTANT.YYYY.MMM’. If its From or To header contains
the string ‘boss’, it will get expired to ‘nnfolder:Work’. All other
mail will get expired to ‘nnfolder:Archive-YYYY’.
If ‘nnmail-keep-last-article’ is non-‘nil’, Gnus will never expire
the final article in a mail newsgroup. This is to make life easier for
procmail users.
By the way: That line up there, about Gnus never expiring
non-expirable articles, is a lie. If you put ‘total-expire’ in the
group parameters, articles will not be marked as expirable, but all read
articles will be put through the expiry process. Use with extreme
caution. Even more dangerous is the ‘gnus-total-expirable-newsgroups’
variable. All groups that match this regexp will have all read articles
put through the expiry process, which means that _all_ old mail articles
in the groups in question will be deleted after a while. Use with
extreme caution, and don’t come crying to me when you discover that the
regexp you used matched the wrong group and all your important mail has
disappeared. Be a _man_! Or a _woman_! Whatever you feel more
comfortable with! So there!
Most people make most of their mail groups total-expirable, though.
If ‘gnus-inhibit-user-auto-expire’ is non-‘nil’, user marking
commands will not mark an article as expirable, even if the group has
auto-expire turned on.
The expirable marks of articles will be removed when copying or
moving them to a group in which auto-expire is not turned on. This is
for preventing articles from being expired unintentionally. On the
other hand, to a group that has turned auto-expire on, the expirable
marks of articles that are copied or moved will not be changed by
default. I.e., when copying or moving to such a group, articles that
were expirable will be left expirable and ones that were not expirable
will not be marked as expirable. So, even though in auto-expire groups,
some articles will never get expired (unless you read them again). If
you don’t side with that behavior that unexpirable articles may be mixed
into auto-expire groups, you can set
‘gnus-mark-copied-or-moved-articles-as-expirable’ to a non-‘nil’ value.
In that case, articles that have been read will be marked as expirable
automatically when being copied or moved to a group that has auto-expire
turned on. The default value is ‘nil’.
Info Catalog
gnus: Incorporating Old Mail
gnus: Getting Mail
gnus: Washing Mail