#+TITLE:mu
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Welcome to ~mu~!

#+begin_html
<img src="assets/email-hazard.jpg" style="float:right" alt="drowning in email"/>
#+end_html

With the enormous amounts of e-mail many people gather and the importance of
e-mail message in our work-flows, it's essential to quickly deal with all that
mail - in particular, to instantly find that one important e-mail you need right
now, and quickly file away message for later use.

~mu~ is a set of command-line tools for dealing with e-mail messages stored in the
[[https://en.wikipedia.org/wiki/Maildir][Maildir]]-format. ~mu~'s goal is to help you to quickly find the messages you need,
view them, extract attachments, and so on.

On top of ~mu~, some related tools are built:

- ~mu4e~: a full-featured e-mail client that runs inside [[https://www.gnu.org/software/emacs/][GNU/Emacs]] (more below)

- ~mu-scm~: bindings for the [[https://www.gnu.org/software/guile/guile.html][Guile/Scheme]] programming language (version 3.0 and
  later)

#+begin_html
<img src="assets/mu-structure.png" alt="mu structure diagram"/>
#+end_html

After indexing your messages into a [[http://www.xapian.org][Xapian]]-database, you can search them through
a query language. You can use various message fields or words in the body text
to find the right messages.

~mu~ is written in C++; ~mu4e~ is written in ~elisp~ and ~mu-scm~ is written in a mix of
C++ and Scheme.

~mu~ is available in many Linux distributions (e.g. Debian/Ubuntu and Fedora)
under the name ~maildir-utils~; apparently because they don't like short names.
All of the code is distributed under the terms of the [[https://www.gnu.org/licenses/gpl-3.0.en.html][GNU General Public License
version 3]] (or higher).

The ~mu~ project welcomes contributions; see the Github issue list and [[IDEAS.org]].

Users and developers are encouraged to join the [[https://groups.google.com/g/mu-discuss/][mu-discuss]] mailing-list.

* Versions

*mu* attempts to balance development speed and stability.

Active development takes place on ~master~ (the 1.14 series), and we maintain the
~release/1.12~ branch as well, for any critical fixes.

Every few months, we release a stable version (e.g. ~1.14.0~); development then
continues in ~master~, with ~-pre<n>~ (e.g. ~1.14.1-pre1~): ~-pre~-suffixed versions
refer to the current _development_ code, until it is released (and then looses its
~-pre~ suffix, i.e., becomes the ~1.14.1~ release).

Hence, generally we recommend the latest 1.14 release; if you want to avoid any
changes except critical bug-fixes, use the latest 1.12 [[https://github.com/djcb/mu/releases/][release]]; and finally, if
you want to track active development, use ~master~.

Overall, we try to avoid incompatible changes, but sometimes this is necessary,
for example to update the versions of required libraries.

* Installation

Note: building from source is an /advanced/ subject, especially if something goes
wrong. The below simple examples are a start, but all tools involved have many
options; there are differences between systems, versions etc. So if this is all
a bit daunting we recommend to wait for someone else to build it for you, such
as a Linux distribution. Many have packages available.

** Requirements

To be able to build ~mu~, ensure you have:

- a C++20 compiler (~gcc~ and ~clang~ are known to work)
- development packages for /Xapian/ and /GMime/ and /GLib/ (see ~meson.build~ for the
  versions)
- basic tools such as ~make~, ~sed~, ~grep~
- ~meson~

For ~mu4e~, you also need ~emacs~, version 28 or later.

Note, support for Windows is very much _experimental_, that is, it works for some
people, but we can't really support it due to lack of the specific expertise.
Help is welcome!

** Building

#+begin_example
$ git clone https://github.com/djcb/mu.git
$ cd mu
#+end_example

~mu~ uses ~meson~ for building, so you can use that directly, and all the usual
commands apply. You can also use it _indirectly_ through the provided ~Makefile~,
which provides a number of useful targets.

For instance, using the ~Makefile~, you could install ~mu~ using:

#+begin_example
$ ./autogen.sh && make
$ sudo make install
#+end_example

You can of course also run ~meson~ directly (see the ~meson~ documentation for more
details):
#+begin_example
$ meson setup build
$ meson compile -C build
$ meson install -C build
#+end_example

* Initial setup

Most ~mu~ commands and ~mu4e~ require setting up the database, which is needed only
once. For this, there is the ~mu init~ command. See its manpage for all the
details, but could look something like:

#+begin_example
$ mu init --maildir=~/Maildir          \
    --personal-address=jim@example.com \
    --personal-address=bob@example.com \
    --ignored-address='.*reply*.'
#+end_example

This creates your database, specifies some of your personal addresses, and some
addresses (a regular expression) that should be ignored from the contacts-cache
used for address-autocompletion in ~mu4e~.

After this step, we can index our maildir:
#+begin_example
$ mu index
#+end_example
The first time you do this, it can take a few minutes, depending on how many
messages you have. Afterwards, you can run ~mu index~ e.g., after retrieving
messages from a remote server.

After that has completed you can try to find some messages with some simple
queries:
#+begin_example
$ mu find hello
#+end_example

* Mu4e

Mu4e is an e-mail client for [[https://www.gnu.org/software/emacs/][GNU/Emacs]] that works on top of ~mu~.

~mu4e~ is shipped as part of the ~mu~ package, and the versions must match.

Since there are so many different ways people use e-mail, there are a lot of
ways to customize it to your needs; see the [[https://www.djcbsoftware.nl/code/mu/mu4e/][Mu4e Reference Manual]] for all the
details, here we include quick-start instructions, in the form of ~use-package~
declaration.

Much of it is commented-out, pick the parts that best fit your particular needs;
see the manual for a deeper dive.

#+begin_src elisp
(use-package mu4e
  :ensure nil
  :config
;;;; Basics

  ;; (setq mu4e-mu-binary "/path/to/mu") ; only needed if mu is not in PATH
  (setq mail-user-agent 'mu4e) ;; mu4e as the default emacs mail program

  ;; Identify yourself. Not strictly necessary.
  ;; (setq
  ;;  user-mail-address "mickey@example.com"
  ;;  user-full-name "Mickey Mouse")

  ;;
;;;; Retrieving mail
  ;;
  ;; Here, put the command you use for getting mail from some
  ;; remote server to your local Maildir. You can leave it at its
  ;; default when you have local delivery (rare these days)
  ;;
  ;; The command depends on your local setup, e.g.:
  ;; "offlineimap", "mbsync", "fetchmail", ... or some shell script
  (setq mu4e-get-mail-command "/bin/true" ;;
        mu4e-update-interval 180)         ;; check every 3 minutes

  ;;
;;;; Reading mail
  ;;
  ;; You need to tell mu4e where it can find certain mail folders
  ;; in your Maildir; these are the paths relative to your maildir-root.
  ;; (setq
  ;;  mu4e-inbox-folder  "/inbox"
  ;;  mu4e-sent-folder   "/sent"
  ;;  mu4e-drafts-folder "/drafts"
  ;;  mu4e-trash-folder  "/trash")
  ;;
  ;; For Gmail, these could look something like:
  ;; (setq
  ;;  mu4e-inbox-folder  "/INBOX"
  ;;  mu4e-sent-folder   "/[Gmail]/Sent Mail"
  ;;  mu4e-drafts-folder "/drafts"
  ;;  mu4e-trash-folder  "/trash")
  ;; ;; (here we keep /drafts & /trash local)

  ;; define some shortcuts to maildirs you use often
  ;; the :key defines the shortcut key, the other parameters
  ;; determine what is (not) shown in the main-view. See the
  ;; `mu4e-maildir-shortcuts' docstring.
  ;; (setq mu4e-maildir-shortcuts
  ;;       '((:maildir "/inbox"       :key ?i :hide-if-no-unread t :favorite t)
  ;;         (:maildir "/lists"       :key ?l :hide-if-no-unread t)
  ;;         (:maildir "/sent"        :key ?s :hide-unread t))))

  ;; Defaults to homedir. Can also be a function, for file-specific
  ;; dirs; see docstring.
  ;; (setq mu4e-attachment-dir "~/Downloads")

  ;;
;;;; Sending mail
  ;;
  ;; Mail sending goes through the Emacs smtpmail package
  ;; the exact settings depend on your SMTP provider
  (setq
   send-mail-function          smtpmail-send-it
   message-send-mail-function  smtpmail-send-it
   ;; smtpmail-smtp-user          "user@example.com"
   ;; smtpmail-smtp-server        "smtp.example.com"
   ;; smtpmail-smtp-service       465
   ;; smtpmail-stream-type        'tls
   )

  ;;
;;;; Extras
  ;;
  ;; There are *many* more settings to customize mu4e. Here are a few common
  ;; ones; just some examples, tweak to your preferences.

  ;; prefer text when mails have both text and html
  ;; (with-eval-after-load "mm-decode"
  ;;   (add-to-list 'mm-discouraged-alternatives "text/html")
  ;;   (add-to-list 'mm-discouraged-alternatives "text/richtext")
  ;;   (add-to-list 'mm-discouraged-alternatives "multipart/related"))

  ;; Some visual tweaks
  (setq mu4e-use-fancy-chars t) ;; allow for unicode emojis

  ;;
  ;;;; Custom bookmarks / queries
  ;; e.g.:
  ;; (add-to-list 'mu4e-bookmarks
  ;;              '( :name  "Inbox messages in the last 7 days"
  ;;                 :query (lambda ()
  ;;                          (format "maildir:/inbox AND date:%s"
  ;;                                  (format-time-string
  ;;                                   "%Y%m%d.."
  ;;                                   (subtract-time (current-time)
  ;;                                                  (days-to-time 7)))))
  ;;                 :key   ?w))

  ;; Tweak headers display; i.e. what headers to show, sizes etc.
  ;; Eg:
  ;; (setq
  ;;  mu4e-headers-date-format "%Y-%m-%d"
  ;;  mu4e-headers-time-format "%H:%M"
  ;;  mu4e-headers-fields
  ;;  '((:human-date     .  10)
  ;;    (:flags          .  4)
  ;;    (:from-or-to     .  20)
  ;;    (:mailing-list   .  8)
  ;;    (:maildir        .  8)
  ;;    (:labels         .  8)
  ;;    (:thread-subject .  nil)))

  ;; Refiling a messages ('r'), i.e., move messages to some other folder,
  ;; based on their properties. mu4e-refile-folder can be a folder-name
  ;; or a function taking a message and returning a folder-name
  ;; (setq mu4e-refile-folder
  ;;         (lambda (msg)
  ;;           (cond
  ;;            ;; all messages sent by me go to the sent folder
  ;;            ((mu4e-message-sent-by-me msg) (mu4e-get-sent-folder msg))
  ;;            ;; all mu-related messages go to the mu folder
  ;;            ((mu4e-message-contact-field-matches msg :to
  ;;                                                 "mu-discuss@googlegroups.com")
  ;;             "/mu")
  ;;            ;; some work-related senders
  ;;            ((seq-some
  ;;              (lambda (addr) (mu4e-message-contact-field-matches msg :from addr))
  ;;              `(,(rx "boss@company.com" eos)
  ;;                ,(rx "lucy@bookkeeper.com" eos)
  ;;                ,(rx "jim@taxes.gov" eos)))
  ;;             "/work")
  ;;            ;; everything else goes to /archive
  ;;            (t
  ;;             "/archive"))))

  ;; Tweak the message-view
  ;; (setq
  ;;  mu4e-view-date-format "%Y-%m-%d %H:%M"
  ;;  mu4e-view-fields
  ;;  '(:from :to :cc :bcc :subject :flags :date :maildir :mailing-list))

  ;; with nerd-icons or all-the-icons installed, you can get some icons when
  ;; view messaages, e.g.
  ;; (setq mu4e-file-name-to-icon-function #'nerd-icons-icon-for-file)
  ;;  or
  ;; (setq mu4e-file-name-to-icon-function #'all-the-icons-icon-for-file)

  ;; Set a message signature:
  ;; (setq message-signature
  ;;       (concat
  ;;        "User McUserFace\n"
  ;;        "http://www.example.com\n"))

  :hook
  ;; tweak the composer
  ((mu4e-compose-mode . (lambda ()
                          (set-fill-column 72)
                          (flyspell-mode)))
   ;; allow for inserting attachments with dired,
   ;;   with `M-x gnus-dired-attach'
   (dired-mode  . turn-on-gnus-dired-mode))

  :bind ;; the Mu4e transient menu
  (("C-c m" . mu4e-transient-menu)))
#+end_src