Welcome to mu!

With the enormous amounts of e-mail many people gather and the importance of e-mail messages in our daily work-flow, it is very important to be able to quickly deal with all that - in particular, to instantly find that one important e-mail you need right now.

For that, mu was created. mu is a tool for dealing with e-mail messages stored in the Maildir-format, on Unix-like systems.

mu’s goal is to help you to find the messages you need, quickly; in addition, it allows you to view messages, extract attachments, create new maildirs, …

Mu’s source code is available in github, and there is the mu-discuss mailing list.

mu consists of a set of command-line utils, mu4e, an email-client for GNU/Emacs and can be scripted using the embedded Guile/Scheme programming language.

Features

• fast indexing for Maildir, Maildir+ and Maildir-on-VFAT
• search for messages based on the sender, receiver, subject, date-range, size, priority, words in message, flags (signed, encrypted, new, replied, has-attachment,…), message-id, maildir, labels, attachment (name, mime-type, text), language
• support for encrypted and signed messages
• command-line tools for indexing, searching, viewing, adding/removing messages, extracting attachments, exporting/searching address lists, creating maildirs, …
• accent/case normalization - so angstrom matches Ångström
• mu4e, an Emacs-based e-mail client
• bindings for GNU Guile, for scripting
• fully documented (man pages, info pages)

Versions

The first mu versions are from 2008, but development has never stopped. The latest version are 1.12 (February 2024) with never versions with fixes and features all the way up to 1.12.13 in September 2025; see the release notes

Development & download

Some Linux-distributions already provide pre-built mu packages; if there’s no packagage for your distribution, or if you want the latest release, you can download mu source packages from Google Code. In case you find a bug, or have a feature requests, please use the issue tracker.

If you’d like to work with the mu source code, you can find it in Github; also, see the notes on HACKING the mu source code.

There’s also a mailing list.

License & Copyright

mu was designed and implemented by Dirk-Jan C. Binnema, and is Free Software, licensed under the GNU GPLv3