mddiff - computes diff for maildirs
mddiff [--max-mailno mno] [--db-file dbf] [-l|--list] [-s|--symlink]
[--exclude globexpr] [-v|--verbose] [-d|--dry-run]
[-n|--no-delete] [--no-move] [--help] [--sha1sum] paths
mddiff computes the delta from an old status of a maildir (previously
recorded in a support file, called db file) and the current status,
generating a set of commands (a diff) that a third party software can
apply to synchronize a (eventually remote) copy of the maildir.
If paths is a single file name, and that file is a fifo, mddiff reads
from it file names separated by new line and outputs the sha1 of its header
and body separated by space.
$ mddiff /tmp/fifo_for_mddiff
If paths is a single file name, and that file is a fifo, and the -s option
is passed, mddiff reads from that fifo two lines at a time, respectively
a source name and a target name. It then creates a symlink named as
as the target name pointing to the source name. If some dictories need to be
created in order to create the symlink, this is also done. mddiff will
print 'OK' on stdout to signal a success, 'ERROR' to signal an error.
If paths is a list of directories, mddiff outputs a list of actions a client
has to perform to synchronize a copy of the same maildirs. This set of actions
is relative to a previous status of the maildir stored in the db file.
The input directories are traversed recursively, and every file encountered
inside directories named cur/ and new/ is a potential mail message (if it
contains no \\n\\n it is skipped).
$ mddiff ~/Mail/
ADD ~/Mail/cur/1239038050.14937_1.garfield:2,S 66532ebb05b252e...
Every client (endpoint using mddiff for synchronization) must use a different
db-file, and the db-file is strictly related with the set of directories given
as arguments, and should not be used with a different directory set. Adding
items to the directory set is safe, while removing them may not do what you
want (delete actions are generated).
mddiff does not alter the dbf file, it generates a new one called dbf.new.
It is up to the higher level tool smd-server(1) to rename dbf.new to dbf
in case the other endpoint successfully applied the diff.
The --exclude option tells mddiff to ignore all paths matching the given
glob(7) expression. This option can be passed multiple times. Matching
is performed using fnmatch(3) with no special flags, thus '*' and '?' match
any character including '/'. Matching is performed when a directory is
entered. If the match is successful, the directory and all its
subedirectories are skipped.
The --no-delete option tells mddiff to not output a DELETE action for
files that disappear. Note that a DELETE action is anyway generated for
files that are moved (i.e. move is COPY plus DELETE). The result is that
deletions are not propagated to the other endpoint.
--max-mailno mno Estimation of max mail message number (defaults to the
number of messages in the db-file + 1000 or 500000
if there is no db-file). You may want to decrease it
for the first run on small systems. It is anyway
increased automatically when needed
--db-file dbf Name of the cache for the endpoint (default db.txt)
--exclude globexpr Exclude paths maching the given expression
--sha1sum Behaves like the sha1sum utility
--mkdir-p Behaves like mkdir -p
--mkfifo Behaves like mkfifo
-l --list Only list the mailboxes recursively contained in paths
-s --symlink Create symlinks for paths read on the input fifo
-v --verbose Increase program verbosity (printed on stderr)
-d --dry-run Do not generate a new db-file
-n --no-delete Do not track deleted files
--no-move Do not generate MOVE (only COPY + DELETE)
--help This help screen
mddiff is a low level utility, used by smd-server and smd-client. You
should use higher level tools like smd-pull(1), smd-push(1) and smd-loop(1)
smd-client(1), smd-server(1), smd-pull(1), smd-push(1), smd-loop(1)
Enrico Tassi <email@example.com>