Several ruminations on this topic can be found on the Internet. None (that is easily found) answers the question though, especially for those not familiar with both formats in detail.
The relevant article on Mozilla wiki notes in its first paragraph: “Thunderbird's maildir implementation allows a single unique filename per email (EML). HOWEVER, note this is NOT full maildir in the sense that most people, particularly linux users or mail administrators, know as maildir.” So, presumably, Thunderbird's stock converter does not offer the proper solution.
dsync but it is presumably developed for dovecot specifically. I want to quit using Thunderbird but I don't intend to use Dovecot right now, with its wiki mentioning some “Maildir++”. Dovecot also recommends (ibid.)
mb2md.pl with some patches of Dovecot's own.
mb2md seems to be what's recommended in general.
However, there are two implementations of
mb2md: a sh+Python script and a Perl script. The former is the original implementation, and its page says literally the following about the Perl version: “if you encounter this particular [seemingly absurdly trivial environment-related] issue with my script, give it [the Perl implementation] a try”, and nothing else. It's not clear whether those two scripts operate the same way or even support the same syntax. (Brief inspection suggests it doesn't; why use the same name then?) Python version is reportedly from 2006 which makes it more than 10 years old as of today. It also so happens that the distribution I use (Gentoo) does not seem to have
mb2md in its repository. I could install Dovecot and use its converter but this doesn't feel right.
Even though the matter might be trivial (mbox is nothing but string concatenation of eml's, right?), all the above is alarming: for a more than 10 year old format (Maildir), widely considered superior to mbox, there apparently is no standard migration mechanism. I don't want to convert blindly, only to find out later that some data was lost, as the
mb2md page warns, or that I can't add more messages to the new Maildir storage without losing consistency, as mentioned in mbsync man page (search for the phrase “native scheme is faster”).
For the record, I intend to use mbsync with the new Maildir storage. Hopefully, the answer would not depend on this.
- Will the 10 year old sh+Python
mb2mdconverter work as fine with modern mboxen as it did with 2006 ones?
- Thunderbird directory contains
Feedssubdirectories, which, in turn, contain other files. Are
INBOXfiles the only mbox files, or I might miss some others?
- Should I convert each mbox file with
mb2mdseparately and do I have to somehow manually connect or group them in Maildir storage?
- In the past, Thunderbird offered “compacting” folders, whatever that means, and the user said yes. Does it affect the conversion process?
- What should I take into account when choosing between different
mb2mdversions? Assume, for the sake of completeness, that tags, PGP encryption and signatures in various forms were heavily used in Thunderbird.