[notmuch-wiki] / howto.mdwn

[[!img notmuch-logo.png alt="Notmuch logo" class="left"]]
# How to...

Some tips about how to do some useful things with notmuch, and the
various "third party" notmuch utilities.

[[!toc levels=2]]

## <span id="receive_mail">**Receive mail**</span>

Notmuch does not fetch mail for you.  For that, you need to use an
external mail syncing utility.  Some recommended utilities are listed
below.

Notmuch requires that every individual message be in its own file.
The well-supported [maildir](http://cr.yp.to/proto/maildir.html) or
"mh"-style storage formats are compatible with notmuch.  Basically any
setup in which each mail is in a file of its own will work.  The older
mbox mail store formats is not supported, but fortunately it is very
easy to [[convert mbox to maildir|howto/#mbox]] .  The following
utilities support these formats:

* [offlineimap](http://offlineimap.org/) -
  quite useful and widely tested, it also offers a handy hook that
  will come in useful a bit later in our setup.  Also supports
  "presynchook" and "postsynchook" command that will get run
  whenever you sync.  Point _postsynchook_ to a script that gets run
  on every sync and that will do the automatic updating and tagging
  of your notmuch database.

* [mbsync](http://isync.sourceforge.net/)

* [getmail](http://pyropus.ca/software/getmail/)

* [fetchmail](http://www.fetchmail.info/)

* [muchsync](http://www.muchsync.org/) - replicate and synchronize
  your notmuch database (mail and tags) across machines

* [gmailieer](https://github.com/gauteh/gmailieer) - Fast email-fetching and two-way tag synchronization between notmuch and GMail

See more exhaustive list of [[software]] notmuch works with and the
[[initial_tagging]] page for more info on initial tagging of messages.


## <span id="send_mail">**Send mail**</span>

Notmuch does not send your mail. The frontends (MUAs) that utilize notmuch
does that. Often these MUAs use sendmail(8) to send your mail.

If you prefer a simpler solution like msmtp, first
[install and configure msmtp](http://msmtp.sourceforge.net/).

Then create a symbolic link so that msmtp will be called instead of sendmail
when you press the keyboard shortcut to send your message.

    $ sudo ln -s /usr/bin/msmtp /usr/sbin/sendmail


## <span id="sync_maildir_flags">**Sync notmuch tags and maildir flags**</span>

notmuch has the ability to synchronize maildir flags and respective tags in both
directions. For more information on maildir flags see the [maildir
page](http://cr.yp.to/proto/maildir.html) and [[Special tags|special-tags]], and for the respective tags see your
notmuch configuration file. This feature is enabled by default, but if you don't
need it, it is simple to disable it with the 'notmuch config' command:

        $ notmuch config set maildir.synchronize_flags false

The maildir flags may, in turn, be synchronized with IMAP flags by another tool,
such as offlineimap.

For safety reasons, and because
[[notmuch does not support delete operations|deleting]], notmuch does
not sync the "trashed" flag.  For discussion on this topic please
refer to the mailing list.

## <span id="python">**Use notmuch from python**</span>

See the [[Notmuch Library Language Bindings|bindings]] page.

## <span id="print_filenames">**Using notmuch with Mutt**</span>

See [[notmuch-mutt]].

## <span id="reapply_auto">**Automatically retagging the database (e.g., when upgrading versions)**</span>

Certain versions of notmuch include new automatic tags (for example, between
0.3 and 0.10, automatic tagging of signed and encrypted messages was added).
However, for users running with databases created in older versions of
notmuch, these tags are missing in pre-existing messages and need to be
added.  One way to do this is as follows:

        $ notmuch dump --output=$HOME/out.nm
        $ mv ~/Mail/.notmuch ~/.notmuch.bak
        $ notmuch new
        $ notmuch tag -inbox -unread '*'
        $ notmuch restore --accumulate --input=$HOME/out.nm

At this point, one should run a sanity check on the tags, and if everything
has merged correctly, the ~/.notmuch.bak directory is expendable, as is
$HOME/out.nm.

## <span id="mbox">**Dealing with mbox and other formats**</span>

notmuch by itself is unable to handle non-maildir mail archives.  One tool
to solve this is called mb2md.  Assuming an mbox in ~/test.mbox and ones
mail archives to be in ~/Mail, an invocation would look like

        $ mb2md -s ~/test.mbox -d ~/Mail/mynewmaildirname

Note that specifying the paths for -s and -d is necessary.  This will create
a new maildir in ~/Mail/mynewmaildirname from the mbox at ~/test.mbox.

Often the formats are more convoluted, however.  Many lists provide an
almost-but-not-quite-mbox format that mailman produces, as can be seen, for
example, [here](http://lists.xapian.org/pipermail/xapian-devel/).  These
files can be converted with some degree of success to mbox using the script
found
[here](http://www.hermann-uwe.de/blog/converting-mailman-gzipd-text-archive-files-to-proper-mbox-files),
and from mbox to maildir as above.

However, many of these lists also have a gmane version, which, where it
exists, achieves far better results than dealing with the messy mailman
output.  Using the instructions from [Gmane's
site](http://gmane.org/export.php), we can download an mbox file, which we
can then convert to maildir using mb2md or other utility.

Please note that mail delivered by Postfix will have envelope headers
that may cause notmuch to complain about "single-message mbox files".
Removing the first line from the message or passing it through
reformail will solve the problem.

## <span id="special_tags">**Take advantage of tags that are special to notmuch**</span>

See [[tags special to notmuch|special-tags]].


## <span id="special_tags">**Index all your gpg-encrypted email**</span>

If you don't mind replacing your encrypted emails with cleartext versions and
re-indexing them, there are some scripts that do that at
[github](https://github.com/mmehnert/maildir-decrypt) . That would make sense
in a scenario where you have encrypted your hard disk anyway and are
comfortable with the security implications (and until notmuch can index
encrypted email itself).

## <span id="special_tags">**Index and search emails written in CJK scripts**</span>

CJK (Chinese, Japanese and Korean) languages do not use spaces for word
separation. The full-text indexer (Xapian) must first perform word segmentation
on the sentence in its TermGenerator. Otherwise, large amount of long terms
will be included in the database, leading to extremely slow indexing and
ineffective searching with CJK search terms.

Xapian supports [N-gram](https://xapian.org/docs/sourcedoc/html/classXapian_1_1TermGenerator.html)
term generator [since 2011](https://u7fa9.org/memo/HEAD/archives/2012-06/2012-06-01.rst)
to as a simple substitute for word segmentation. It can be turned on by
setting the environment variable

        $ export XAPIAN_CJK_NGRAM=1
        $ notmuch new

For existing databases, one can reindex the database (since notmuch 0.26)
with

        $ export XAPIAN_CJK_NGRAM=1
        $ notmuch reindex '*'

Xapian has an on-going [pull-request](https://github.com/xapian/xapian/pull/114)
that adds support for real CJK word-segmentation based on the ICU library.
When it gets merged, one probably will gets better indexing and searching
results with this new method.

## Translations

- A translation of this page into [[Russian|howto-ru]]