mpack

encodes files into MIME format for email transmission

TLDR

Encode file as a MIME message to a file

$ mpack -o [output.mime] [file]

Encode and mail the file to one or more recipients

$ mpack -s "[Subject]" [file] [user@example.com]

Encode to stdout for piping into another mailer

$ mpack -o - [file]

Fragment a large file into multiple messages of at most 100 000 chars each

$ mpack -s "[Subject]" -m [100000] [large_file] [user@example.com]

Force a specific MIME content type

$ mpack -c application/pdf [report.pdf] [user@example.com]

Post the file to a Usenet newsgroup instead of e-mail

$ mpack -n [comp.misc] [file]

mpack [-a] [-s subject] [-d descriptionfile] [-m maxsize] [-c content-type] file address...mpack [-a] [-s subject] [-d descriptionfile] [-m maxsize] [-c content-type] -o outputfile filempack [-a] [-s subject] [-d descriptionfile] [-m maxsize] [-c content-type] -n newsgroups file

DESCRIPTION

mpack encodes a binary or text file into one or more MIME-formatted messages, optionally mailing them to a list of addresses or posting them to a newsgroup. It generates the necessary headers (MIME-Version, Content-Type, Content-Transfer-Encoding, Content-Disposition) and base64-encodes binary content. With -m, the message is split into independently mailable fragments that munpack can reassemble at the other end.

PARAMETERS

-s subject

Email subject line.

-d descriptionfile

Include the contents of descriptionfile as an introductory text part before the attachment.

-m maxsize

Fragment the message into chunks no larger than maxsize characters (0 = no limit).

-c content-type

Override the MIME Content-Type of the attachment (e.g. application/pdf, image/png).

-a

Mark the encoded file as an attachment (Content-Disposition: attachment) rather than inline.

-o outputfile

Write the encoded message to outputfile (use - for stdout). When fragmenting, numbered suffixes are appended.

-n newsgroups

Post to the named Usenet newsgroup(s) instead of mailing.

INSTALL

sudo apt install mpack

brew install mpack

nix profile install nixpkgs#mpack

CAVEATS

Companion to munpack. Sending mail or posting requires a configured local MTA (sendmail-compatible) or news transport. Fragmented messages must all reach the recipient and be reassembled with munpack before decoding.

HISTORY

mpack was written by John G. Myers at Carnegie Mellon as part of the MIME tools for handling binary email attachments.