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How to...

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

  1. How to...
    1. Receive mail
    2. Send mail
    3. Sync notmuch tags and maildir flags
    4. Use notmuch from python
    5. Using notmuch with Mutt
    6. Automatically retagging the database (e.g., when upgrading versions)
    7. Dealing with mbox and other formats
    8. Take advantage of tags that are special to notmuch
    9. Index all your gpg-encrypted email
    10. Index and search emails written in CJK scripts
    11. Translations

Receive mail

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 it's own file. The well-supported maildir 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 . The following utilities support these formats:

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

Send mail

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.

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

Sync notmuch tags and maildir flags

notmuch has the ability to synchronize maildir flags and respective tags in both directions. For more information on maildir flags see the maildir page and 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, notmuch does not sync the "trashed" flag. For discussion on this topic please refer to the mailing list.

Use notmuch from python

See the Notmuch Library Language Bindings page.

Using notmuch with Mutt

See notmuch-mutt.

Automatically retagging the database (e.g., when upgrading versions)

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.

Dealing with mbox and other formats

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. These files can be converted with some degree of success to mbox using the script found here, 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, 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.

Take advantage of tags that are special to notmuch

See tags special to notmuch.

Index all your gpg-encrypted email

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 . 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).

Index and search emails written in CJK scripts

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 term generator since 2011 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 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.