Sync gmail to local imap server.

Uses Ubuntu 18.04 Server Base Install.

imapsync Setup

Clone imapsync repo.
git clone
Install perl dependencies.
apt install libio-tee-perl libmail-imapclient-perl libterm-readkey-perl libunicode-string-perl libcrypt-openssl-rsa-perl libdata-uniqid-perl libjson-perl liblwp-online-perl libreadonly-perl libfile-copy-recursive-perl libio-socket-inet6-perl libsys-meminfo-perl libregexp-common-perl libfile-tail-perl libauthen-ntlm-perl libcgi-pm-perl libclass-load-perl libcrypt-ssleay-perl libdigest-hmac-perl libdist-checkconflicts-perl libencode-imaputf7-perl libio-compress-perl libio-socket-ssl-perl libmodule-scandeps-perl libnet-dbus-perl libnet-ssleay-perl libpar-packer-perl libtest-fatal-perl libtest-mock-guard-perl libtest-mockobject-perl libtest-pod-perl libtest-requires-perl libtest-simple-perl liburi-perl libtest-nowarnings-perl libtest-deep-perl libtest-warn-perl libjson-webtoken-perl cpanminus make


Meeting prerequisites can be determined by running ./INSTALL.d/prerequisities_imapsync.

Create secured password files, enter passwords.
touch .ssh/imapsync_{personal,gmail}
chmod 0600 .ssh/imapsync_{personal,gmail}


  • Remote server is gmail, uses application specific password. Setup here.

  • Local server is your personal IMAP server. Use IMAP password.

  • Use .ssh directory here since it’s already secured.

Set password files readonly.
chmod 0400 .ssh/imapsync_{personal,gmail}


Test sync to ensure connecting properly.
./imapsync --dry \
--host1 --port1 993 --user1 {GMAIL EMAIL USER} --passfile1 ~/.ssh/imapsync_gmail --ssl1 \
--host2 {YOUR IMAP SERVER} --port2 993 --user2 {YOUR IMAP USER} --passfile2 ~/.ssh/imapsync_personal --ssl2 \
--subfolder2 gmail-archive --minage 30 --exitwhenover 2500000000 --delete --expunge1
  • This will sync mail older than 30 days, and remove it from gmail.

  • Gmail has a download limit of 2.5GB’s a day, this will safetly exit when reached.

  • Ensure connections work, folders are identified, and local folder is set properly.

Install Service

Install imapsync to /opt/imapsync.
sudo git checkout-index -a -f --prefix=/opt/imapsync/
  • Set /opt/imapsync permissions according to your system, ensure imapsync is executable.

Create bash script using /opt/imapsync, typically in ~/bin.

/opt/imapsync/imapsync \
--host1 --port1 993 --user1 {GMAIL EMAIL USER} --passfile1 ~/.ssh/imapsync_gmail --ssl1 \
--host2 {YOUR IMAP SERVER} --port2 993 --user2 {YOUR IMAP USER} --passfile2 ~/.ssh/imapsync_personal --ssl2 \
--subfolder2 gmail-archive --minage 30 --exitwhenover 2500000000 --delete --expunge1 \
--nolog &>/dev/null

Add to local crontab to run nightly.

crontab -e
* 3 * * * ~/bin/gmail_to_imap_sync

Removing Duplicates On Local Maildir

When sync’ing imap servers, you may end up with duplicates (e.g. if you have copied a message to multiple accounts and they are now all synced to one account.)

Generate a list of duplicates.
sudo apt install fdupes
find USER_MAIL -type d -name cur -print0 | xargs -0 /usr/bin/fdupes -n > out
Download / configure / run imap-de-dupe.go.
go get
go build src/



  1. Error installing imapsync