Mail Client Neomutt

Christian Külker

0.1.1 2023-07-27

Introduction

Neomutt and mutt are renowned command-line clients, also referred to as Mail User Agents (MUA). They allow users to send and receive emails directly from the terminal. While traditional local mail is efficiently managed by these tools, with some configuration, they can also handle IMAP (and POP3). In the past, I used tools like elm and pine, which had relatively simple user interfaces; mutt and neomutt continue in that tradition. My preference for neomutt over mutt is primarily due to its superior IMAP handling. That said, I haven’t explored all the alternatives, so there might be better MUAs available. Feedback is welcome. This guide outlines the challenges faced when setting up basic mail functionalities in neomutt or mutt—functionalities that are typically available out-of-the-box in graphical interfaces.

IMAP Mail box naming

Surprisingly, renaming one’s IMAP folder in the sidebar to something other than INBOX can be quite challenging. With older versions of mutt, it might even be impossible.

Dependencies

Autocrypt

Autocrypt requires sqlite3 as dependency. While the configuration (./configure) works on Debian 9.13 Stretch and 10 Bullseye, the compilation with --autocrypt will stop for Debian 9.13 Stretch with an error.

autocrypt/db.c:272:9: warning: implicit declaration of function
    ‘sqlite3_prepare_v3’ [-Wimplicit-function-declaration]
     if (sqlite3_prepare_v3(AutocryptDB,
         ^~~~~~~~~~~~~~~~~~
autocrypt/db.c:281:32: error: ‘SQLITE_PREPARE_PERSISTENT’ undeclared (first use
                            in this function)
                            -1, SQLITE_PREPARE_PERSISTENT, &AccountGetStmt,
                            NULL) != SQLITE_OK)

To successfully compile neomutt on Debian 9.13 Stretch, exclude the --autocrypt and --sqlite options from the ./configure command.

gettext

To use nls, you need gettext. If it’s not required, you can disable it with the --disable-nls flag.

aptitude install gettext

Ncurses

To utilize the ncurses user interface, the associated development library must be installed.

aptitude install libncurses-dev

libidn

The stringprep.h file requires the libidn11-dev package.

aptitude install libidn11-dev

gpgme

aptitude install libgpgme11-dev

SASL

aptitude install libsasl2-dev

Krb5

aptitude install libkrb5-dev

SQLite

Autocrypt requires sqlite

aptitude install libsqlite3-dev

GNU TLS

aptitude install gnutls-dev

Notmuch

aptitude install notmuch notmuch-mutt libnotmuch-dev

Hcache

While older version of neomutt (around 2016) had the configure option --hcache and this option actually shows up in neomutt -v it seems to be that the configure script do not want to know this option any more. However hcache will be used if a back-end is configured. Not all have been tested.

gdbm
bdb
kyotocabinet
lmdb (tested)
qdbm
rocksdb
tdb
tokyocabinet

Header compression: (not tested)

lz4
zlib
zstd

For the Berkeley Database (current 5.3) probably do

aptitude install libdb-dev

However, it’s not been tested. The tested backend was lmdb, which performed without issues.

aptitude install liblmdb-dev

Build

Building neomutt follows the conventional process for C programs: configure, make, and make install. Optional targets (goals) include neomutt and test. The compilation is both quick and reliable.

mkdir -p /srv/build
mkdir  -p /srv/src
cd  /srv/src
export V=20220429
export URL=https://github.com/neomutt/neomutt/archive/refs/tags/$V.tar.gz
wget -O neomutt-$V.tar.gz $URL
cd /srv/build
tar xvzf ../src/neomutt-$V.tar.gz
cd neomutt-$v
./configure --disable-doc --prefix=/srv/neomutt-20220429

Minimal Debian 9.13 Stretch configuration

Summary of build options:

  Version:               20220429
  Host OS:               linux-gnu
  Install prefix:        /srv/neomutt-20220429
  Compiler:               cc
  CFlags:                -g -O2 -std=c99 -D_ALL_SOURCE=1 -D_GNU_SOURCE=1 \
                         -D__EXTENSIONS__ -DNCURSES_WIDECHAR \
                         -I/srv/neomutt-20220429/include
  LDFlags:               -L/srv/neomutt-20220429/lib
  Libs:                  -lidn -lncursesw -ltinfo -lanl

  GPGME:                 no
  PGP:                   yes
  SMIME:                 yes
  Notmuch:               no
  Header Cache(s):
  Header Compression(s):
  Lua:                   no

Minimal Debian 11 Bullseye configuration_

Summary of build options:

  Version:               20220429
  Host OS:               linux-gnu
  Install prefix:        /srv/neomutt-20220429
  Compiler:               cc
  CFlags:                -g -O2 -std=c99 -D_ALL_SOURCE=1 -D_GNU_SOURCE=1 \
                         -D__EXTENSIONS__ -DNCURSES_WIDECHAR \
                         -I/srv/neomutt-20220429/include
  LDFlags:               -L/srv/neomutt-20220429/lib
  Libs:                  -lidn -lncursesw -ltinfo -lanl

  GPGME:                 no
  PGP:                   yes
  SMIME:                 yes
  Notmuch:               no
  Header Cache(s):
  Header Compression(s):
  Lua:                   no

Certain features need to be specified via ./configure to be able to use them later. In case you would like to create a neomutt configuration similar to an installed version, you can use neomutt -v to show the used ./configure options. Some options like sidebar are already enabled as default options.

The following ./configure option have been used for Debian.

            Stretch Buster Bullseye Remark
            9.13    10     11
--autocypt  no             yes      Enable AutoCrypt support (requires GPGME)
--gnutls    yes            yes      Enable TLS support using GnuTLS
--gpgme     yes            yes      Enable GPGME support
--gss       yes            yes      Use GSSAPI authentication for IMAP
--lmdb      yes            yes      Use LMDB for the header cache
--pgp       yes            yes      PGP support
--prefix    yes            yes      Install path
--sasl      yes            yes      Use the SASL network security library
--smime     yes            yes      SMIME support
--sqlite    no             yes      Enable SQLite support
--mixmaster yes            yes      Enable Mixmaster support
--notmuch   yes            yes      Enable Notmuch support

./configure --disable-doc --prefix=/srv/neomutt-20220429 --autocrypt --gnutls\
  --gpgme --gss --pgp --sasl --smime --sqlite --lmdb --mixmaster --notmuch\
  --disable-maintainer-mode

When comparing the above configurations to the Debian 11 Bullseye neomutt ./configure options, it’s evident that selecting the right options for neomutt is not straightforward. Kudos to the Debian 11 Bullseye team for their configuration choices.

--build=x86_64-linux-gnu --prefix=/usr {--includedir=${prefix}/include}\
 {--mandir=${prefix}/share/man} {--infodir=${prefix}/share/info}\
 --sysconfdir=/etc --localstatedir=/var --disable-option-checking\
 --disable-silent-rules {--libdir=${prefix}/lib/x86_64-linux-gnu}\
 {--libexecdir=${prefix}/lib/x86_64-linux-gnu}\
 --disable-maintainer-mode --disable-dependency-tracking\
 --mandir=/usr/share/man --libexecdir=/usr/libexec --with-mailpath=/var/mail\
 --gpgme --lua --notmuch --with-ui --gnutls --gss --idn --mixmaster --sasl\
 --tokyocabinet --sqlite --autocrypt

This are the summaries for the less complex configuration for Debian 9.13 Stretch.

Summary of build options:

  Version:               20220429
  Host OS:               linux-gnu
  Install prefix:        /srv/neomutt-20220429
  Compiler:               cc
  CFlags:                -g -O2 -std=c99 -D_ALL_SOURCE=1 -D_GNU_SOURCE=1
                         -D__EXTENSIONS__ -I/srv/neomutt-20220429/include
                         -DNCURSES_WIDECHAR -isystem /usr/include/mit-krb5
  LDFlags:               -L/srv/neomutt-20220429/lib
                         -L/usr/lib/x86_64-linux-gnu/mit-krb5 -Wl,-z,relro
                         -lgssapi_krb5 -lkrb5 -lk5crypto -lcom_err
  Libs:                  -lidn -lgnutls -lncursesw -ltinfo -lsqlite3 -lsasl2
                         -lgpgme -lanl  -L/usr/lib/x86_64-linux-gnu -lgpgme
                         -lassuan -lgpg-error -L/usr/lib/x86_64-linux-gnu
                         -lgpg-error
  GPGME:                 yes
  PGP:                   yes
  SMIME:                 yes
  Notmuch:               no
  Header Cache(s):
  Header Compression(s):
  Lua:                   no

Debian 11 Bullseye

Summary of build options:

  Version:               20220429
  Host OS:               linux-gnu
  Install prefix:        /srv/neomutt-20220429
  Compiler:               cc
  CFlags:                -g -O2 -std=c99 -D_ALL_SOURCE=1 -D_GNU_SOURCE=1 
                         -D__EXTENSIONS__ -I/srv/neomutt-20220429/include 
                         -DNCURSES_WIDECHAR -isystem /usr/include/mit-krb5
  LDFlags:               -L/srv/neomutt-20220429/lib 
                         -L/usr/lib/x86_64-linux-gnu/mit-krb5 -Wl,-z,relro 
                         -lgssapi_krb5 -lkrb5 -lk5crypto -lcom_err
  Libs:                  -llmdb -lidn -lgnutls -lncursesw -ltinfo -lsqlite3 
                         -lsasl2 -lgpgme -lanl  -L/usr/lib/x86_64-linux-gnu 
                         -lgpgme -lassuan -lgpg-error 
                         -L/usr/lib/x86_64-linux-gnu -lgpg-error
  GPGME:                 yes
  PGP:                   yes
  SMIME:                 yes
  Notmuch:               no
  Header Cache(s):       lmdb
  Header Compression(s):
  Lua:                   no

Installation

As is standard, the make install command transfers files to the specified --prefix location. For Debian 9.13 Stretch and 11 Bullseye, a minimal configuration will copy the following files. Note: internationalization files are excluded from this list.

├── bin
│   └── neomutt
├── etc
│   └── neomuttrc
├── libexec
│   └── neomutt
│       ├── pgpewrap
│       └── smime_keys
└── share
    ├── doc
    │   └── neomutt
    │       ├── colorschemes
    │       │   ├── neonwolf-256.neomuttrc
    │       │   ├── solarized-dark-256.neomuttrc
    │       │   ├── vombatidae.neomuttrc
    │       │   └── zenburn.neomuttrc
    │       ├── hcache-bench
    │       │   ├── neomutt-hcache-bench.sh
    │       │   ├── neomuttrc
    │       │   └── README.md
    │       ├── keybase
    │       │   ├── attachmentView.png
    │       │   ├── decrypt.sh
    │       │   ├── install.sh
    │       │   ├── keybase.py
    │       │   ├── LICENSE
    │       │   ├── neomuttrc
    │       │   ├── pagerMode.png
    │       │   ├── pgpdecrypt.sh
    │       │   ├── pgpverify.sh
    │       │   ├── README.md
    │       │   └── verify.sh
    │       ├── logo
    │       │   ├── neomutt-128.png
    │       │   ├── neomutt-256.png
    │       │   ├── neomutt-32.png
    │       │   ├── neomutt-64.png
    │       │   └── neomutt.svg
    │       ├── lua
    │       │   ├── test_lua-api_runner.neomuttrc
    │       │   └── test_lua-api_spec.lua
    │       ├── oauth2
    │       │   ├── mutt_oauth2.py
    │       │   └── mutt_oauth2.py.README
    │       ├── samples
    │       │   ├── colors.default
    │       │   ├── colors.linux
    │       │   ├── gpg.rc
    │       │   ├── mairix_filter.pl
    │       │   ├── markdown2html.py
    │       │   ├── Mush.rc
    │       │   ├── Pine.rc
    │       │   ├── sample.mailcap
    │       │   ├── sample.neomuttrc
    │       │   ├── sample.neomuttrc-starter
    │       │   ├── sample.neomuttrc-tlr
    │       │   ├── smime_keys_test.pl
    │       │   ├── smime.rc
    │       │   └── Tin.rc
    │       └── vim-keys
    │           ├── README.md
    │           └── vim-keys.rc
    ...

History

Version	Date	Notes
0.1.1	2023-07-27	Improve style, grammar, release to quick guide
0.1.0	2022-07-18	Initial release

Last modified (via git): July 27, 2023
Improve style, grammar, release to quick guide (61ef4706)
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