Guide | Attachment Converter

Attachment Converter is an open-source command-line tool for digital archivists. Given an email mailbox in MBOX format, it will go through that mailbox and batch convert all the attachments it can into preservation formats, putting a converted copy of each attachment back into the email from which it originated. The user can then re-open the new mailbox in a mail user agent, such as Apple Mail, and browse through the mailbox the normal way.

For batch conversion and report creation, Attachment Converter assumes the input to be an MBOX file (.mbox). MBOX files are human-readable and universally established as a supported inbox file format. If your inbox file is already in the .mbox format, then skip to the "Basic Commands" section.

If you have an Outlook .pst file, we have found Libpst to be a useful utility for performing that conversion. Once installed, you can run:

$ readpst example.pst

For other file formats, please be sure to find a utility capable of converting your current file to .mbox.

By default, attc will expect an inbox file .mbox and will batch convert any attachments within an email in the inbox. For ease of use, cd into the directory containing your inbox file and run:

$ attc < example.mbox > example-converted.mbox

Running this command creates a new inbox file. Inside the converted emails, you will find both the original file and the converted file attached to the email.

To simply convert the attachments within one email file .eml, run:

$ attc --single-email < example-email.eml > example-email-converted.eml

You can also replace --single-email with its shorter name -s.

Attachment Converter also supports running a report on an inbox. This feature allows you to examine the content types of the attachments in an inbox without performing any conversions. Reports in Attachment Converter list the total number of files that match each MIME type.

To run a report on an inbox file .mbox, run:

$ attc --report < example.mbox

Your report will ressemble the following:

Content Types:
  application/msword : 19
  application/octet-stream : 7
  application/pdf : 219
  application/rtf : 3
  application/vnd.openxmlformats-officedocument.presentationml.presentation : 2
  application/vnd.openxmlformats-officedocument.wordprocessingml.document : 41
  application/zip : 2
  image/gif : 67
  image/jpeg : 271
  image/jpg : 6
  image/pjpeg : 6
  image/png : 498
  image/tiff : 1
  message/rfc822 : 11
  multipart/mixed : 8643
  multipart/signed : 2
  text/calendar : 2
  text/html : 8341
  text/plain : 302

You can also replace --report with its shorter name -r.