NAME
  mddiff - computes diff for maildirs
SYNOPSIS
  mddiff [--max-mailno mno] [--db-file dbf] [-v|--verbose] [--help] 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 list of regular files, mddiff outputs the sha1 of its header
  and body separated by space.

      $ mddiff Mail/cur/1239038050.14937_1.garfield:2,S Mail/cur/123...
      806a0ffe4f29766effd764... 463e543da9dac8e298...
      582cbb6a5cd3ce13965c8c... 8fa60a7458b1157193...
      ...
  
  If paths is a list of directories, mddiff outputs a list of actions a client
  has to perform to syncronize 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... 
      ...
  
  Regular files and directories cannot be mixed in paths.
  
  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.

OPTIONS
  --max-mailno mno      Estimation of max mail message number (default 500000)
                        Decrease for small systems, it is increased
                        automatically if needed
  --db-file dbf         Name of the cache for the endpoint (default db.txt)
  -v --verbose          Increase program verbosity (printed on stderr)
  --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 <gares@fettunta.org>
