IMAP to IMAP batch mailbox migration. Requires imapsync (http://imapsync.lamiral.info/)

imapsync.sh

#!/usr/bin/php
#
# Usage: ./imapsync.sh accounts.csv
#
# CSV account schema:
# old_username;old_password;new_username;new_password
#
<?php

define('HOST_FROM', 'imap.example.com');
define('HOST_TO', 'imap.example.org');
define('DOMAIN', 'example.com');

if(!$argv[1]) die("USAGE: ".$argv[0]." <csv_file>\n\n");
$fh = fopen($argv[1], 'r+');
$contents = fread($fh, filesize($argv[1]));
fclose($fh);
$cn = explode("\n",$contents);

foreach($cn as $c):
        $n = explode(";",$c);
        if($n[0]!=""):
        $cmd = "/usr/bin/imapsync \
        --host1 ".HOST_FROM." --user1 ".$n[0]." --password1 ".$n[1]." \
        --host2 ".HOST_TO." --user2 ".$n[2]."@".DOMAIN." --password2 ".$n[3]." \
        --subscribed --subscribe --useheader Message-ID --idatefromheader --authmech1 LOGIN --authmech2 LOGIN --ssl2 \
        --buffersize 614400000 --skipsize";
        passthru($cmd);
        endif;
endforeach;
?>

Debian setup:

apt-get install libmail-imapclient-perl libdigest-md5-file-perl \
libterm-readkey-perl libio-socket-ssl-perl libfile-spec-perl libdigest-hmac-perl

perl -MCPAN -e 'install Authen::NTLM'

Perl CPAN setup:

perl -MCPAN -e 'install Mail::IMAPClient' 
perl -MCPAN -e 'install Digest::MD5' 
perl -MCPAN -e 'install Term::ReadKey' 
perl -MCPAN -e 'install IO::Socket::SSL' 
perl -MCPAN -e 'install File::Spec' 
perl -MCPAN -e 'install Digest::HMAC_MD5' 
perl -MCPAN -e 'install Authen::NTLM' 
perl -MCPAN -e 'install Time::HiRes'