NAME imapsync - Email IMAP tool for syncing, copying, migrating and archiving email mailboxes between two imap servers, one way, and without duplicates. VERSION This documentation refers to Imapsync $Revision: 1.977 $ USAGE To synchronize the source imap account "test1" on server "test1.lamiral.info" with password "secret1" to the destination imap account "test2" on server "test2.lamiral.info" with password "secret2" do: imapsync \ --host1 test1.lamiral.info --user1 test1 --password1 secret1 \ --host2 test2.lamiral.info --user2 test2 --password2 secret2 DESCRIPTION We sometimes need to transfer mailboxes from one imap server to one another. Imapsync command is a tool allowing incremental and recursive imap transfers from one mailbox to another. If you don't understand the previous sentence, it's normal, it's pedantic computer oriented jargon. All folders are transferred, recursively, meaning the whole folder hierarchy is taken, all messages in them, and all messages flags (\Seen \Answered \Flagged etc.) are synced too. Imapsync reduces the amount of data transferred by not transferring a given message if it already resides on the destination side. Messages that are on the destination side but not on the source side stay as they are (see the --delete2 option to have a strict sync). How imapsync knows a message is already on both sides? Same specific headers and the transfer is done only once. By default, the identification headers are "Message-Id:" and "Received:" lines but this choice can be changed with the --useheader option. All flags are preserved, unread messages will stay unread, read ones will stay read, deleted will stay deleted. You can abort the transfer at any time and restart it later, imapsync works well with bad connections and interruptions, by design. On a terminal hit Ctr-c twice within two seconds in order to abort the program. Hit Ctr-c just once makes imapsync reconnect to both imap servers. A classical scenario is synchronizing a mailbox B from another mailbox A where you just want to keep a strict copy of A in B. Strict meaning all messages in A will be in B but no more. For this, option --delete2 has to be used, it deletes messages in host2 folder B that are not in host1 folder A. If you also need to destroy host2 folders that are not in host1 then use --delete2folders. See also --delete2foldersonly and --delete2foldersbutnot to set up exceptions on folders to destroy. INBOX will never be destroy, it's a mandatory folder in IMAP. A different scenario is to delete the messages from the source mailbox after a successful transfer, it can be a good feature when migrating mailboxes since messages will be only on one side. The source account will only have messages that are not on the destination yet, ie, messages that arrived after a sync or that failed to be copied. In that case, use the --delete1 option. Option --delete1 implies also option --expunge1 so all messages marked deleted on host1 will be really deleted. In IMAP protocol deleting a message does not really delete it, it marks it with the flag \Deleted, allowing an undelete. Expunging a folder removes, definitively, all the messages marked as \Deleted in this folder. You can also decide to remove empty folders once all of their messages have been transferred. Add --delete1emptyfolders to obtain this behavior. Imapsync is not adequate for maintaining two active imap accounts in synchronization when the user plays independently on both sides. Use offlineimap (written by John Goerzen) or mbsync (written by Michael R. Elkins) for a 2 ways synchronization. OPTIONS usage: imapsync [options] The standard options are the six values forming the credentials. Three values on each side are needed in order to log in into the IMAP servers. These six values are a host, a username, and a password, two times. Conventions used in the following descriptions of the options: str means string int means integer reg means regular expression cmd means command --dry : Makes imapsync doing nothing for real, just print what would be done without --dry. OPTIONS/credentials --host1 str : Source or "from" imap server. --port1 int : Port to connect on host1. Optional since default ports are the well known ports imap/143 or imaps/993. --user1 str : User to login on host1. --password1 str : Password for the user1. --host2 str : "destination" imap server. --port2 int : Port to connect on host2. Optional --user2 str : User to login on host2. --password2 str : Password for the user2. --showpasswords : Shows passwords on output instead of "MASKED". Useful to restart a complete run by just reading the command line used in the log, or to debug passwords. It's not a secure practice at all. --passfile1 str : Password file for the user1. It must contain the password on the first line. This option avoids showing the password on the command line like --password1 does. --passfile2 str : Password file for the user2. You can also pass the passwords in the environment variables IMAPSYNC_PASSWORD1 and IMAPSYNC_PASSWORD2 OPTIONS/encryption --nossl1 : Do not use a SSL connection on host1. --ssl1 : Use a SSL connection on host1. On by default if possible. --nossl2 : Do not use a SSL connection on host2. --ssl2 : Use a SSL connection on host2. On by default if possible. --notls1 : Do not use a TLS connection on host1. --tls1 : Use a TLS connection on host1. On by default if possible. --notls2 : Do not use a TLS connection on host2. --tls2 : Use a TLS connection on host2. On by default if possible. --debugssl int : SSL debug mode from 0 to 4. --sslargs1 str : Pass any ssl parameter for host1 ssl or tls connection. Example: --sslargs1 SSL_verify_mode=1 --sslargs1 SSL_version=SSLv3 See all possibilities in the new() method of IO::Socket::SSL http://search.cpan.org/perldoc?IO::Socket::SSL#Description_Of_Methods --sslargs2 str : Pass any ssl parameter for host2 ssl or tls connection. See --sslargs1 --timeout1 int : Connection timeout in seconds for host1. Default is 120 and 0 means no timeout at all. --timeout2 int : Connection timeout in seconds for host2. Default is 120 and 0 means no timeout at all. OPTIONS/authentication --authmech1 str : Auth mechanism to use with host1: PLAIN, LOGIN, CRAM-MD5 etc. Use UPPERCASE. --authmech2 str : Auth mechanism to use with host2. See --authmech1 --authuser1 str : User to auth with on host1 (admin user). Avoid using --authmech1 SOMETHING with --authuser1. --authuser2 str : User to auth with on host2 (admin user). --proxyauth1 : Use proxyauth on host1. Requires --authuser1. Required by Sun/iPlanet/Netscape IMAP servers to be able to use an administrative user. --proxyauth2 : Use proxyauth on host2. Requires --authuser2. --authmd51 : Use MD5 authentication for host1. --authmd52 : Use MD5 authentication for host2. --domain1 str : Domain on host1 (NTLM authentication). --domain2 str : Domain on host2 (NTLM authentication). OPTIONS/folders --folder str : Sync this folder. --folder str : and this one, etc. --folderrec str : Sync this folder recursively. --folderrec str : and this one, etc. --folderfirst str : Sync this folder first. Ex. --folderfirst "INBOX" --folderfirst str : then this one, etc. --folderlast str : Sync this folder last. --folderlast "[Gmail]/All Mail" --folderlast str : then this one, etc. --nomixfolders : Do not merge folders when host1 is case-sensitive while host2 is not (like Exchange). Only the first similar folder is synced (example: with folders "Sent", "SENT" and "sent" on host1 only "Sent" will be synced to host2). --skipemptyfolders : Empty host1 folders are not created on host2. --include reg : Sync folders matching this regular expression --include reg : or this one, etc. If both --include --exclude options are used, then include is done before. --exclude reg : Skips folders matching this regular expression Several folders to avoid: --exclude 'fold1|fold2|f3' skips fold1, fold2 and f3. --exclude reg : or this one, etc. --automap : guesses folders mapping, for folders well known as "Sent", "Junk", "Drafts", "All", "Archive", "Flagged". --f1f2 str1=str2 : Force folder str1 to be synced to str2, --f1f2 overrides --automap and --regextrans2. --subfolder2 str : Syncs the whole host1 folders hierarchy under the host2 folder named str. It does it internally by adding three --regextrans2 options before all others. Add --debug to see what's really going on. --subfolder1 str : Syncs the host1 folders hierarchy which is under folder str to the root hierarchy of host2. It's the couterpart of a sync done by --subfolder2 when doing it in the reverse order. Backup/Restore scenario: Use --subfolder2 str for a backup to the folder str on host2. Then use --subfolder1 str for restoring from the folder str, after inverting host1/host2 user1/user2 values. --subscribed : Transfers subscribed folders. --subscribe : Subscribe to the folders transferred on the host2 that are subscribed on host1. On by default. --subscribeall : Subscribe to the folders transferred on the host2 even if they are not subscribed on host1. --prefix1 str : Remove prefix str to all destination folders, usually "INBOX." or "INBOX/" or an empty string "". imapsync guesses the prefix if host1 imap server does not have NAMESPACE capability. So this option should not be used most of the time. --prefix2 str : Add prefix to all host2 folders. See --prefix1 --sep1 str : Host1 separator. This option should not be used most of the time. Imapsync gets the separator from the server itself, by using NAMESPACE, or it tries to guess it from the folders listing (it counts characters / . \\ \ in folder names and choose the more frequent, or finally / if nothing is found. --sep2 str : Host2 separator. See --sep1 --regextrans2 reg : Apply the whole regex to each destination folders. --regextrans2 reg : and this one. etc. When you play with the --regextrans2 option, first add also the safe options --dry --justfolders Then, when happy, remove --dry for a run, then remove --justfolders for the next ones. Have in mind that --regextrans2 is applied after the automatic prefix and separator inversion. For examples see: https://imapsync.lamiral.info/FAQ.d/FAQ.Folders_Mapping.txt OPTIONS/folders sizes --nofoldersizes : Do not calculate the size of each folder at the beginning of the sync. Default is to calculate them. --nofoldersizesatend: Do not calculate the size of each folder at the end of the sync. Default is to calculate them. --justfoldersizes : Exit after having printed the initial folder sizes. OPTIONS/tmp --tmpdir str : Where to store temporary files and subdirectories. Will be created if it doesn't exist. Default is system specific, Unix is /tmp but /tmp is often too small and deleted at reboot. --tmpdir /var/tmp should be better. --pidfile str : The file where imapsync pid is written, it can be dirname/filename. Default name is imapsync.pid in tmpdir. --pidfilelocking : Abort if pidfile already exists. Useful to avoid concurrent transfers on the same mailbox. OPTIONS/log --nolog : Turn off logging on file --logfile str : Change the default log filename (can be dirname/filename). --logdir str : Change the default log directory. Default is LOG_imapsync/ The default logfile name is for example LOG_imapsync/2019_12_22_23_57_59_532_user1_user2.txt where: 2019_12_22_23_57_59_532 is nearly the date of the start YYYY_MM_DD_HH_MM_SS_mmm year_month_day_hour_minute_seconde_millisecond and user1 user2 are the --user1 --user2 values. OPTIONS/messages --skipmess reg : Skips messages matching the regex. Example: 'm/[\x80-ff]/' # to avoid 8bits messages. --skipmess is applied before --regexmess --skipmess reg : or this one, etc. --skipcrossduplicates : Avoid copying messages that are already copied in another folder, good from Gmail to X when X is not also Gmail. Activated with --gmail1 unless --noskipcrossduplicates --debugcrossduplicates : Prints which messages (UIDs) are skipped with --skipcrossduplicates (and in what other folders they are). --pipemess cmd : Apply this cmd command to each message content before the copy. --pipemess cmd : and this one, etc. With several --pipemess, the output of each cmd command (STDOUT) is given to the input (STDIN) of the next command. For example, --pipemess cmd1 --pipemess cmd2 --pipemess cmd3 is like a Unix pipe: "cat message | cmd1 | cmd2 | cmd3" --disarmreadreceipts : Disarms read receipts (host2 Exchange issue) --regexmess reg : Apply the whole regex to each message before transfer. Example: 's/\000/ /g' # to replace null by space. --regexmess reg : and this one, etc. OPTIONS/labels Gmail present labels as folders in imap. Imapsync can accelerate the sync by syncing X-GM-LABELS, it will avoid to transfer messages when they are already on host2. --synclabels : Syncs also Gmail labels when a message is copied to host2. Activated by default with --gmail1 --gmail2 unless --nosynclabels is added. --resynclabels : Resyncs Gmail labels when a message is already on host2. Activated by default with --gmail1 --gmail2 unless --noresynclabels is added. For Gmail syncs, see also: https://imapsync.lamiral.info/FAQ.d/FAQ.Gmail.txt OPTIONS/flags If you encounter flag problems see also: https://imapsync.lamiral.info/FAQ.d/FAQ.Flags.txt --regexflag reg : Apply the whole regex to each flags list. Example: 's/"Junk"//g' # to remove "Junk" flag. --regexflag reg : then this one, etc. --resyncflags : Resync flags for already transferred messages. On by default. --noresyncflags : Do not resync flags for already transferred messages. May be useful when a user has already started to play with its host2 account. OPTIONS/deletions --delete1 : Deletes messages on host1 server after a successful transfer. Option --delete1 has the following behavior: it marks messages as deleted with the IMAP flag \Deleted, then messages are really deleted with an EXPUNGE IMAP command. If expunging after each message slows down too much the sync then use --noexpungeaftereach to speed up, expunging will then be done only twice per folder, one at the beginning and one at the end of a folder sync. --expunge1 : Expunge messages on host1 just before syncing a folder. Expunge is done per folder. Expunge aims is to really delete messages marked deleted. An expunge is also done after each message copied if option --delete1 is set (unless --noexpungeaftereach). --noexpunge1 : Do not expunge messages on host1. --delete1emptyfolders : Deletes empty folders on host1, INBOX excepted. Useful with --delete1 since what remains on host1 is only what failed to be synced. --delete2 : Delete messages in host2 that are not in host1 server. Useful for backup or pre-sync. --delete2 implies --uidexpunge2 --delete2duplicates : Delete messages in host2 that are duplicates. Works only without --useuid since duplicates are detected with an header part of each message. --delete2folders : Delete folders in host2 that are not in host1 server. For safety, first try it like this (it is safe): --delete2folders --dry --justfolders --nofoldersizes and see what folders will be deleted. --delete2foldersonly reg : Delete only folders matching the regex reg. Example: --delete2foldersonly "/^Junk$|^INBOX.Junk$/" This option activates --delete2folders --delete2foldersbutnot reg : Do not delete folders matching the regex rex. Example: --delete2foldersbutnot "/Tasks$|Contacts$|Foo$/" This option activates --delete2folders --noexpunge2 : Do not expunge messages on host2. --nouidexpunge2 : Do not uidexpunge messages on the host2 account that are not on the host1 account. OPTIONS/dates If you encounter problems with dates, see also: https://imapsync.lamiral.info/FAQ.d/FAQ.Dates.txt --syncinternaldates : Sets the internal dates on host2 same as host1. Turned on by default. Internal date is the date a message arrived on a host (Unix mtime). --idatefromheader : Sets the internal dates on host2 same as the ones in "Date:" headers. OPTIONS/message selection --maxsize int : Skip messages larger (or equal) than int bytes --minsize int : Skip messages smaller (or equal) than int bytes --maxage int : Skip messages older than int days. final stats (skipped) don't count older messages see also --minage --minage int : Skip messages newer than int days. final stats (skipped) don't count newer messages You can do (+ zone are the messages selected): past|----maxage+++++++++++++++>now past|+++++++++++++++minage---->now past|----maxage+++++minage---->now (intersection) past|++++minage-----maxage++++>now (union) --search str : Selects only messages returned by this IMAP SEARCH command. Applied on both sides. For a complete set of what can be search see https://imapsync.lamiral.info/FAQ.d/FAQ.Messages_Selection.txt --search1 str : Same as --search but for selecting host1 messages only. --search2 str : Same as --search but for selecting host2 messages only. So --search CRIT equals --search1 CRIT --search2 CRIT --maxlinelength int : skip messages with a line length longer than int bytes. RFC 2822 says it must be no more than 1000 bytes but real life servers and email clients do more. --useheader str : Use this header to compare messages on both sides. Ex: Message-ID or Subject or Date. --useheader str and this one, etc. --usecache : Use cache to speed up next syncs. Not set by default. --nousecache : Do not use cache. Caveat: --useuid --nousecache creates duplicates on multiple runs. --useuid : Use UIDs instead of headers as a criterion to recognize messages. Option --usecache is then implied unless --nousecache is used. OPTIONS/miscellaneous --syncacls : Synchronizes acls (Access Control Lists). Acls in IMAP are not standardized, be careful since one acl code on one side may signify something else on the other one. --nosyncacls : Does not synchronize acls. This is the default. --addheader : When a message has no headers to be identified, --addheader adds a "Message-Id" header, like "Message-Id: 12345@imapsync", where 12345 is the imap UID of the message on the host1 folder. OPTIONS/debugging --debug : Debug mode. --debugfolders : Debug mode for the folders part only. --debugcontent : Debug content of the messages transferred. Huge output. --debugflags : Debug mode for flags. --debugimap1 : IMAP debug mode for host1. Very verbose. --debugimap2 : IMAP debug mode for host2. Very verbose. --debugimap : IMAP debug mode for host1 and host2. Twice very verbose. --debugmemory : Debug mode showing memory consumption after each copy. --errorsmax int : Exit when int number of errors is reached. Default is 50. --tests : Run local non-regression tests. Exit code 0 means all ok. --testslive : Run a live test with test1.lamiral.info imap server. Useful to check the basics. Needs internet connection. --testslive6 : Run a live test with ks2ipv6.lamiral.info imap server. Useful to check the ipv6 connectivity. Needs internet. OPTIONS/specific --gmail1 : sets --host1 to Gmail and other options. See FAQ.Gmail.txt --gmail2 : sets --host2 to Gmail and other options. See FAQ.Gmail.txt --office1 : sets --host1 to Office365 and other options. See FAQ.Exchange.txt --office2 : sets --host2 to Office365 and other options. See FAQ.Exchange.txt --exchange1 : sets options for Exchange. See FAQ.Exchange.txt --exchange2 : sets options for Exchange. See FAQ.Exchange.txt --domino1 : sets options for Domino. See FAQ.Domino.txt --domino2 : sets options for Domino. See FAQ.Domino.txt OPTIONS/behavior --maxmessagespersecond int : limits the number of messages transferred per second. --maxbytespersecond int : limits the average transfer rate per second. --maxbytesafter int : starts --maxbytespersecond limitation only after --maxbytesafter amount of data transferred. --maxsleep int : do not sleep more than int seconds. On by default, 2 seconds max, like --maxsleep 2 --abort : terminates a previous call still running. It uses the pidfile to know what process to abort. --exitwhenover int : Stop syncing and exits when int total bytes transferred is reached. --version : Print only software version. --noreleasecheck : Do not check for any new imapsync release. --releasecheck : Check for new imapsync release. it's an http request to http://imapsync.lamiral.info/prj/imapsync/VERSION --noid : Do not send/receive ID command to imap servers. --justconnect : Just connect to both servers and print useful information. Need only --host1 and --host2 options. Obsolete since "imapsync --host1 imaphost" alone implies --justconnect --justlogin : Just login to both host1 and host2 with users credentials, then exit. --justfolders : Do only things about folders (ignore messages). --help : print this help. Example: to synchronize imap account "test1" on "test1.lamiral.info" to imap account "test2" on "test2.lamiral.info" with test1 password "secret1" and test2 password "secret2" imapsync \ --host1 test1.lamiral.info --user1 test1 --password1 secret1 \ --host2 test2.lamiral.info --user2 test2 --password2 secret2 SECURITY You can use --passfile1 instead of --password1 to give the password since it is safer. With --password1 option, on Linux, any user on your host can see the password by using the 'ps auxwwww' command. Using a variable (like IMAPSYNC_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. Imapsync activates ssl or tls encryption by default, if possible. What detailed behavior is under this "if possible"? Imapsync activates ssl if the well known port imaps port (993) is open on the imap servers. If the imaps port is closed then it open a normal (clear) connection on port 143 but it looks for TLS support in the CAPABILITY list of the servers. If TLS is supported then imapsync goes to encryption. If the automatic ssl and the tls detections fail then imapsync will not protect against sniffing activities on the network, especially for passwords. If you want to force ssl or tls just use --ssl1 --ssl2 or --tls1 --tls2 See also the document FAQ.Security.txt in the FAQ.d/ directory or at https://imapsync.lamiral.info/FAQ.d/FAQ.Security.txt EXIT STATUS Imapsync will exit with a 0 status (return code) if everything went good. Otherwise, it exits with a non-zero status. That's classical Unix behavior. Here is the list of the exit code values (an integer between 0 and 255). The names reflect their meaning: EX_OK => 0 ; #/* successful termination */ EX_USAGE => 64 ; #/* command line usage error */ EX_NOINPUT => 66 ; #/* cannot open input */ EX_UNAVAILABLE => 69 ; #/* service unavailable */ EX_SOFTWARE => 70 ; #/* internal software error */ EXIT_CATCH_ALL => 1 ; # Any other error EXIT_BY_SIGNAL => 6 ; # Should be 128+n where n is the sig_num EXIT_PID_FILE_ERROR => 8 ; EXIT_CONNECTION_FAILURE => 10 ; EXIT_TLS_FAILURE => 12 ; EXIT_AUTHENTICATION_FAILURE => 16 ; EXIT_SUBFOLDER1_NO_EXISTS => 21 ; EXIT_WITH_ERRORS => 111 ; EXIT_WITH_ERRORS_MAX => 112 ; EXIT_TESTS_FAILED => 254 ; # Like Test::More API LICENSE AND COPYRIGHT Imapsync is free, open, public but not always gratis software cover by the NOLIMIT Public License, now called NLPL. See the LICENSE file included in the distribution or just read this simple sentence as it IS the licence text: "No limits to do anything with this work and this license." In case it is not long enough, I repeat: "No limits to do anything with this work and this license." Look at https://imapsync.lamiral.info/LICENSE AUTHOR Gilles LAMIRAL Good feedback is always welcome. Bad feedback is very often welcome. Gilles LAMIRAL earns his living by writing, installing, configuring and teaching free, open and often gratis software. Imapsync used to be "always gratis" but now it is only "often gratis" because imapsync is sold by its author, a good way to maintain and support free open public software over decades. BUGS AND LIMITATIONS See https://imapsync.lamiral.info/FAQ.d/FAQ.Reporting_Bugs.txt IMAP SERVERS supported See https://imapsync.lamiral.info/S/imapservers.shtml HUGE MIGRATION If you have many mailboxes to migrate think about a little shell program. Write a file called file.txt (for example) containing users and passwords. The separator used in this example is ';' The file.txt file contains: user001_1;password001_1;user001_2;password001_2 user002_1;password002_1;user002_2;password002_2 user003_1;password003_1;user003_2;password003_2 user004_1;password004_1;user004_2;password004_2 user005_1;password005_1;user005_2;password005_2 ... On Unix the shell program can be: { while IFS=';' read u1 p1 u2 p2; do imapsync --host1 imap.side1.org --user1 "$u1" --password1 "$p1" \ --host2 imap.side2.org --user2 "$u2" --password2 "$p2" ... done ; } < file.txt On Windows the batch program can be: FOR /F "tokens=1,2,3,4 delims=; eol=#" %%G IN (file.txt) DO imapsync ^ --host1 imap.side1.org --user1 %%G --password1 %%H ^ --host2 imap.side2.org --user2 %%I --password2 %%J ... The ... have to be replaced by nothing or any imapsync option. Welcome in shell or batch programming ! You will find already written scripts at https://imapsync.lamiral.info/examples/ INSTALL Imapsync works under any Unix with Perl. Imapsync works under most Windows (2000, XP, Vista, Seven, Eight, Ten and all Server releases 2000, 2003, 2008 and R2, 2012 and R2, 2016) as a standalone binary software called imapsync.exe, usually launched from a batch file in order to avoid always typing the options. There is also a 64bit binary called imapsync_64bit.exe Imapsync works under OS X as a standalone binary software called imapsync_bin_Darwin Purchase latest imapsync at https://imapsync.lamiral.info/ You'll receive a link to a compressed tarball called imapsync-x.xx.tgz where x.xx is the version number. Untar the tarball where you want (on Unix): tar xzvf imapsync-x.xx.tgz Go into the directory imapsync-x.xx and read the INSTALL file. As mentioned at https://imapsync.lamiral.info/#install the INSTALL file can also be found at https://imapsync.lamiral.info/INSTALL.d/INSTALL.ANY.txt It is now split in several files for each system https://imapsync.lamiral.info/INSTALL.d/ CONFIGURATION There is no specific configuration file for imapsync, everything is specified by the command line parameters and the default behavior. HACKING Feel free to hack imapsync as the NOLIMIT license permits it. SIMILAR SOFTWARE See also https://imapsync.lamiral.info/S/external.shtml for a better up to date list. Last updated and verified on Sun Dec 8, 2019. imapsync: https://github.com/imapsync/imapsync (this is an imapsync copy, sometimes delayed, with --noreleasecheck by default since release 1.592, 2014/05/22) imap_tools: https://web.archive.org/web/20161228145952/http://www.athensfbc.com/imap_tools/. The imap_tools code is now at https://github.com/andrewnimmo/rick-sanders-imap-tools imaputils: https://github.com/mtsatsenko/imaputils (very old imap_tools fork) Doveadm-Sync: https://wiki2.dovecot.org/Tools/Doveadm/Sync ( Dovecot sync tool ) davmail: http://davmail.sourceforge.net/ offlineimap: http://offlineimap.org/ mbsync: http://isync.sourceforge.net/ mailsync: http://mailsync.sourceforge.net/ mailutil: https://www.washington.edu/imap/ part of the UW IMAP toolkit. (well, seems abandoned now) imaprepl: https://bl0rg.net/software/ http://freecode.com/projects/imap-repl/ imapcopy (Pascal): http://www.ardiehl.de/imapcopy/ imapcopy (Java): https://code.google.com/archive/p/imapcopy/ imapsize: http://www.broobles.com/imapsize/ migrationtool: http://sourceforge.net/projects/migrationtool/ imapmigrate: http://sourceforge.net/projects/cyrus-utils/ larch: https://github.com/rgrove/larch (derived from wonko_imapsync, good at Gmail) wonko_imapsync: http://wonko.com/article/554 (superseded by larch) pop2imap: http://www.linux-france.org/prj/pop2imap/ (I wrote that too) exchange-away: http://exchange-away.sourceforge.net/ SyncBackPro: http://www.2brightsparks.com/syncback/sbpro.html ImapSyncClient: https://github.com/ridaamirini/ImapSyncClient MailStore: https://www.mailstore.com/en/products/mailstore-home/ mnIMAPSync: https://github.com/manusa/mnIMAPSync imap-upload: http://imap-upload.sourceforge.net/ (A tool for uploading a local mbox file to IMAP4 server) imapbackup: https://github.com/rcarmo/imapbackup (A Python script for incremental backups of IMAP mailboxes) BitRecover email-backup 99 USD, 299 USD https://www.bitrecover.com/email-backup/. ImportExportTools: https://addons.thunderbird.net/en-us/thunderbird/addon/importexporttools/ ImportExportTools for Mozilla Thunderbird by Paolo Kaosmos. ImportExportTools does not do IMAP. HISTORY I initially wrote imapsync in July 2001 because an enterprise, called BaSystemes, paid me to install a new imap server without losing huge old mailboxes located in a far away remote imap server, accessible by an often broken low-bandwidth ISDN link. I had to verify every mailbox was well transferred, all folders, all messages, without wasting bandwidth or creating duplicates upon resyncs. The imapsync design was made with the beautiful rsync command in mind. Imapsync started its life as a patch of the copy_folder.pl script. The script copy_folder.pl comes from the Mail-IMAPClient-2.1.3 perl module tarball source (more precisely in the examples/ directory of the Mail-IMAPClient tarball). So many happened since then that I wonder if it remains any lines of the original copy_folder.pl in imapsync source code.