dedup – A changelog by Daniel Mettler

If you need to delete duplicate e-mail messages on an IMAP server, take a look at this useful IMAP de-duplicator script:

IMAP de-duplicator – IMAPdedup

As IMAPdedup is a command line interface tool (a python script), it’s particularly useful for:

automated deletion of duplicates (as it can be called from other scripts)
extraordinarily big mailboxes or if you have many subfolders (as there’s no intervention by the user required)
if you have console/shell access to the IMAP server (as you can then run the script on the server itself, speeding the de-duplication process further up)

I also found that it deals relatively well with failures (e.g. when a folder is read-only and hence messages can’t be deleted): It simply reports them on the screen and carries on.

Here’s a quick’n’dirty bash script to de-dup the inbox and all subfolders of the specified account:

#!/bin/sh
# Delete all duplicate messages in all folders of said account.
# Note that we connect through SSL (-x) to the default port.

SERVER="my.server.com"
USER="mylogin"
PASS="mypass"

for folder in `imapdedup.py -s $SERVER -x -u $USER -w $PASS -l`;
do
 imapdedup.py -s $SERVER -x -u $USER -w $PASS $folder
done

If you only have to de-duplicate messages in a small folder, you could also use the following de-duplication add-on for Mozilla Thunderbird:

Remove Duplicate Messages Add-on for Thunderbird

Note however that the ‘Remove Duplicate Messages’ add-on is intended for interactive use only, not for batch processing. I also noticed that it fails at cleaning big mail folders (e.g. containing 50’000 messages).

Tag: dedup

Delete duplicate e-mail messages