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MU-EXTRACT(1) General Commands Manual MU-EXTRACT(1)


mu_extract - display and save message parts (attachments), and open them with other tools.


mu extract [options] <file>

mu extract [options] <file> <pattern>


mu extract is the mu sub-command for extracting MIME-parts (e.g., attachments) from mail messages. The sub-command works on message files, and does not require the message to be indexed in the database.

For attachments, the file name used when saving it is the name of the attachment in the message. If there is no such name, or when saving non-attachment MIME-parts, a name is derived from the message-id of the message.

If you specify a pattern (a case-insensitive regular expression) as the second argument, all attachments with filenames matching that pattern will be extracted. The regular expressions are Perl-compatible (as per the PCRE-library).

Without any options, mu extract simply outputs the list of leaf MIME-parts in the message. Only 'leaf' MIME-parts (including RFC822 attachments) are considered, multipart/* etc. are ignored.


save all MIME-parts that look like attachments.

save all non-multipart MIME-parts.

only consider the following numbered parts (comma-separated list). The numbers for the parts can be seen from running mu extract without any options but only the message file.

save the parts in the target directory rather than the current working directory.

overwrite existing files with the same name; by default overwriting is not allowed.

application for the particular file type. On MacOS, this uses the open program, on other platforms it uses xdg-open. You can choose a different program by setting the MU_PLAY_PROGRAM environment variable.


To display information about all the MIME-parts in a message file:

$ mu extract msgfile

To extract MIME-part 3 and 4 from this message, overwriting existing files with the same name:

$ mu extract --parts=3,4 --overwrite msgfile

To extract all files ending in '.jpg' (case-insensitive):

$ mu extract msgfile '.*.jpg'

To extract an mp3-file, and play it in the default mp3-playing application:

$ mu extract --play msgfile 'whoopsididitagain.mp3'


Please report bugs if you find them:


Dirk-Jan C. Binnema <>



July 2012 User Manuals