man imapsync (Commandes) - IMAP synchronization, copy or migration tool. Synchronize mailboxes between two imap servers. Good at IMAP migration.


imapsync - IMAP synchronization, copy or migration tool. Synchronize mailboxes between two imap servers. Good at IMAP migration.

$Revision: 1.125 $


 imapsync works fine under any Unix OS.
 imapsync works fine under Windows 2000 (at least) and ActiveState's 5.8 Perl

 Get imapsync at

 You'll find a compressed tarball called imapsync-x.xx.tgz
 where x.xx is the version number. Untar the tarball where
 you want :

 tar xzvf  imapsync-x.xx.tgz

 Go into the directory imapsync-x.xx and read the INSTALL

 The freshmeat record is


  imapsync [options]

  imapsync --help

  imapsync [--host1 server1]  [--port1 <num>]
           [--user1 <string>] [--passfile1 <string>] 
           [--host2 server2]  [--port2 <num>]
           [--user2 <string>] [--passfile2 <string>] 
           [--folder <string> --folder <string> ...]
           [--include <regex>] [--exclude <regex>]
           [--prefix2 <string>]
           [--sep1 <char>]
           [--sep2 <char>]
           [--maxsize <int>]
           [--maxage <int>]
           [--skipheader <regex>]
           [--delete] [--expunge]
           [--subscribed] [--subscribe]
           [--debug] [--debugimap]
           [--timeout <int>]
           [--version] [--help]


The command imapsync is a tool allowing incremental and recursive imap transfer from one mailbox to another.

We sometimes need to transfer mailboxes from one imap server to another. This is called migration.

imapsync is the adequate tool because it reduces the amount of data transfered by not transfering a given message if it is already on both sides. Same headers, same message size and the transfert is done only once. All flags are preserved, unread will stay unread, read will stay read, deleted will stay deleted. You can stop the transfert at any time and restart it later, imapsync is adapted to a bad connection.

You can decide to delete the messages from the source mailbox after a successful transfert (it is a good feature when migrating). In that case, use the --delete option, and run imapsync again with the --expunge option.

You can also just synchronize a mailbox A from another mailbox B in case you just want to keep a live copy of B in A.


Invoke: imapsync --help


I wrote imapsync because an enterprise (basystemes) paid me to install a new imap server without loosing huge old mailboxes located on a far away remote imap server accessible by a low bandwith link. The tool imapcp (written in python) could not help me because I had to verify every mailbox was well transfered and delete it after a good transfert. imapsync started its life being a patch. The tool comes from the Mail-IMAPClient-2.1.3 perl module tarball source (in the examples/ directory of the tarball).


While working on imapsync parameters please run imapsync in dry mode (no modification induced) with the --dry option. Nothing bad can be done this way.

To synchronize the imap account buddy on host to the imap account max on host (the passwords are located in too files /etc/secret1 for buddy, /etc/secret2 for max) :

 imapsync --host1  --user1 buddy --passfile1 /etc/secret1 \
          --host2 --user2 max   --passfile2 /etc/secret2

Then, you will have buddy's mailbox updated from max's mailbox.


You can use --password1 instead of --passfile1 to give the password but it is dangerous because any user on your host can see the password by using the 'ps auxwwww' command. Using a variable (like CW$PASSWORD1) is also dangerous because of the 'ps auxwwwwe' command. So, saving the password in a well protected file (600 or rw-------) is the best solution.

imasync is not protected against sniffers on the network so the passwords are in plain text.


imapsync will exit with a 0 status (return code) if everything went good. Otherwise, it exits with a non-zero status.

So if you have a buggy internet connection, you can use this loop in a Bourne shell:

        while ! imapsync ...; do 
              echo imapsync not complete




imapsync is free, gratis and open source software cover by the GNU General Public License. See the GPL file included in the distribution or the web site


No known serious bug.

Multiple copies: Multiple copies of the emails on the destination server. Some IMAP servers (Domino for example) add some headers for each message transfered. The message is transfered again and again each time you run imapsync. This is bad of course. The explanation is that imapsync considers the message is not the same since headers have changed (one line added) and size too (the header part). You can look at the headers found by imapsync by using the --debug option (and search for the message on both part). The way to avoid this problem is by using options --skipheader and --skipsize, like this (avoid headers beginning whith X-):

 imapsync ... --skipheader '^X-' --skipsize

You can use --skipheader only one time; if you need to skip several different headers use the or perl regex caracter which is |. Example:

 imapsync ... --skipheader '^X-|^Status|^Bcc'

Flags : with some IMAP servers the flags are not very well copied the first time. Run imapsync twice if you want the flags set correctly. (fixed since 1.28 release but wait for a time before removing those lines)

Report any bugs to the author:


Success stories reported with the following imap servers (softwares inames are in alphabetic order) :

 - BincImap 1.2.3
 - CommunicatePro server (Redhat 8.0)
 - Courier IMAP 1.5.1, 2.2.0, 2.1.1, 2.2.1
 - Critical Path (7.0.020)
 - Cyrus IMAP 1.5, 1.6, 2.1, 2.1.15, 2.1.16,
   2.2.1, 2.2.2-BETA, 2.2.10
 - DBMail 1.2.1
 - Dovecot
 - Domino (Notes) 6.5, 5.0.6, 5.0.7
 - iPlanet Messaging server 4.15, 5.1
 - IMail 7.15 (Ipswitch/Win2003), 8.12
 - MDaemon 7.0.1
 - MS Exchange Server 5.5
 - Netscape Mail Server 3.6 (Wintel !)
 - Netscape Messaging Server 4.15 Patch 7
 - OpenWave
 - Qualcomm Worldmail (NT)
 - Samsung Contact IMAP server 8.5.0
 - SunONE Messaging server 5.2, 6.0 (SUN JES - Java Enterprise System)
 - UW-imap servers (imap-2000b) rijkkramer IMAP4rev1 2000.287
   (RedHat uses UW like 2003.338rh)
 - UW - QMail v2.1

Please report to the author any success or bad story with imapsync and don't forget to mention the IMAP server software names and version on both sides. This will help future users. To help the author maintaining this section report the two lines at the begining of the output if they are useful to know the softwares. Example:

 From software :* OK louloutte Cyrus IMAP4 v1.5.19 server ready
 To   software :* OK Courier-IMAP ready

You can use option --justconnect to get those lines.

And please rate imapsync at


Have a special attention on options --subscribed --subscribe --delete --expunge --maxage --maxsize

If you have many mailboxes to migrate think about a little shell program. Write a file called file.csv (for example) containing users and passwords. The separator used in this example is ';'

The file.csv file content is :

user0001;password0001;user0002;password0002 user0011;password0011;user0012;password0012 ...

And the shell program is just :

{ while IFS=';' read u1 p1 u2 p2; do imapsync --user1 CW$u1 --password1 CW$p1 --user2 CW$u2 --password2 CW$p2 ... done ; } < file.csv

Welcome in shell programming !


Feel free to hack imapsync as the GPL Licence permits it.


Entries for imapsync:


  offlineimap :
  mailsync    :
  imapxfer    :
                part of the imap-utils from UW.
  mailutil    : replace imapxfer in 
                part of the imap-utils from UW.
  imaprepl    :
  imapcopy    :
  pop2imap    :

Feedback (good or bad) will be always welcome.


Gilles LAMIRAL earn his living writing, installing, configuring and teaching free open and gratis softwares. Don't hesitate to pay him for that services.

$Id: imapsync,v 1.125 2005/04/22 01:12:18 gilles Exp $