mu-init - Man Page

initialize the mu message database


mu [common-options] init [options]


mu init is the subcommand for setting up the mu message database. After mu init has completed, you can run mu index

Init Options

-m, --maildir=<maildir>

starts searching at <maildir>. By default, mu uses whatever the MAILDIR environment variable is set to; if it is not set, it tries ~/Maildir if it already exists.


specifies that some e-mail addresses are 'my-address' (the option can be used multiple times). Any message in which at least one of the contact fields contains such an address is considered a 'personal' messages; this can then be used for filtering in mu-find(1), mu-cfind(1) and mu4e, e.g. to filter-out mailing list messages.

<my-email-address> can be either a plain e-mail address (such as, or a basic PCRE regular-expression (see pcre(3) for details), wrapped in / (such as /foo-.*@example\.com/). Depending on your shell, the argument may need to be quoted.


reinitialize the database from an earlier version; that is, create a new empty database witht the existing settings. This cannot be combined with the other init options.

Exit Code

This command returns 0 upon successful completion, or a non-zero exit code otherwise. Typical values are 2 (no matches found), 11 (database schema mismatch) and 12 (failed to acquire database lock).

no matches found (2)

Nothing matching found; try a different query

database schema mismatch (11)

You need to re-initialize mu, see mu-init(1)

failed to acquire lock (19)

Some other program has exclusive access to the mu (Xapian) database


use a non-default directory to store and read the database, write the logs, etc. By default, mu uses the XDG Base Directory Specification (e.g. on GNU/Linux this defaults to ~/.cache/mu and ~/.config/mu). Earlier versions of mu defaulted to ~/.mu, which now requires --muhome=~/.mu.

The environment variable MUHOME can be used as an alternative to --muhome. The latter has precedence.

Reporting Bugs

Please report bugs at


Dirk-Jan C. Binnema <>

See Also

mu-index(1), mu-find(1), mu-cfind(1), pcre(3)

Referenced By

mu(1), mu-easy(7), mu-index(1).