mddiff(1)
NAME
mddiff - computes diff for maildirs
SYNOPSIS
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
DESCRIPTION
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
806a0ffe4f29766effd764... 463e543da9dac8e298...
582cbb6a5cd3ce13965c8c... 8fa60a7458b1157193...
...
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.
OPTIONS
--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
NOTES
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)
SEE ALSO
smd-client(1), smd-server(1), smd-pull(1), smd-push(1), smd-loop(1)
AUTHOR
Enrico Tassi <[email protected]> 18 November 2015 mddiff(1)
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