i’ve been using mutt as my mua for over 8 years now. long ago i would ssh to my server and run it on local maildirs, but as soon as i started using smartphones and multiple computers i had to switch to an imap+ssl setup. mutt’s
header_cache option has long made accessing large mailboxes snappy, and the recent
message_cachedir option available in 1.5 makes browsing through messages with attachments equally snappy over imap.
a useful side effect of message body caching is that it provides an offline copy of entire mailboxes which get synchronized automatically and can easily be read in mutt as a local mailbox… well, almost.
because the message caches are just stored in a directory one-message-per-file and one-mailbox-per-directory, this doesn’t match any known mailbox format so mutt will just error out saying it’s not a mailbox when trying to read it with
mutt -f. however, if those messages are saved to a
cur/ subdirectory and a
new/ subdirectory is also present, mutt will recognize it as a maildir and read it properly. yes, the files inside the
cur/ directory will not have “proper” names with a colon, version number, comma, and flags, but it’s enough to get mutt to read them.
i made a patch to mutt 1.5.18 that changes the message cache functions to write to a
cur/ subdirectory and ensure that a
new/ subdirectory also exists. with these in place and all of your folders cached, an offline muttrc can be created:
source ~/.muttrc unset spoolfile unset folder unset postponed unset record # required to prevent imap connections even though spoolfile and folder are changed, # for some reason set imap_passive=yes # point to the appropriate directories set spoolfile=~/.mutt-cache/imaps:firstname.lastname@example.org/inbox/ set folder=~/.mutt-cache/imaps:email@example.com/
and then mutt can be invoked as (or an
offline_mutt shell alias set to):
mutt -R -F ~/.muttrc.offline
which will provide read-only views of all of your mailboxes and retain all of the other macros and searching, filtering, and other functions you already have configured in mutt. note: not using
-R may change message flags which will rename the cache files and cause them to get out of sync.