imapsync script to migrate multiple IMAP accounts in a row

accounts.list

# <SRCUSER> <SRCPW> <DSTUSER> <DSTPW>

imapsync.sh

#!/bin/bash

############# CONFIGURATION ###########
ACCOUNTS=accounts.list
SRCHOST=imap.example.com
DSTHOST=imap.onlime.ch
#######################################

EXTRALOG=sync.log
TSFORMAT="%Y-%m-%d %H:%M:%S"

# loop through all accounts
grep -ve '^#.*' $ACCOUNTS | while read SRCUSER SRCPW DSTUSER DSTPW
do
    MESSAGE="[`date +"$TSFORMAT"`] synchronizing $SRCUSER@$SRCHOST to $DSTUSER@$DSTHOST ..."
    echo $MESSAGE
    echo $MESSAGE >> $EXTRALOG

    # security: temporarly store passwords to files in order 
    # not to pass them directly by command line option
    echo -n $SRCPW > imap-secret-src
    echo -n $DSTPW > imap-secret-dst

    ## VARIANT 1) source host supports SSL/TLS (imap port 993)
    imapsync --host1 $SRCHOST --ssl1 --port1 993 --authmech1 PLAIN --user1 $SRCUSER --passfile1 imap-secret-src \
             --host2 $DSTHOST --ssl2 --port2 993 --authmech2 PLAIN --user2 $DSTUSER --passfile2 imap-secret-dst \
             --delete2 --delete2folders

    ## VARIANT 2) source host does not support SSL/TLS (imap port 143)
    #imapsync --host1 $SRCHOST        --port1 143 --authmech1 PLAIN --user1 $SRCUSER --passfile1 imap-secret-src \
    #         --host2 $DSTHOST --ssl2 --port2 993 --authmech2 PLAIN --user2 $DSTUSER --passfile2 imap-secret-dst \
    #         --delete2 --delete2folders

    ## VARIANT 3) source host has different INBOX prefix, transform it while syncing
    #imapsync --host1 $SRCHOST --ssl1 --port1 993 --authmech1 PLAIN --user1 $SRCUSER --passfile1 imap-secret-src \
    #         --host2 $DSTHOST --ssl2 --port2 993 --authmech2 PLAIN --user2 $DSTUSER --passfile2 imap-secret-dst \
    #         --delete2 --delete2folders
    #         --regextrans2 "s/INBOX.INBOX/INBOX/"

    rm -f imap-secret-*
done

MESSAGE="[`date +"$TSFORMAT"`] imapsync sucessfully completed!"
echo $MESSAGE
echo $MESSAGE >> $EXTRALOG
exit 0

Sorry if I am silly, but I failt to see the reason why sending pw to a file and then picking it up with a --passfile1 is safer than directly using the variable. You are risking to leave a file behind which wouldn't happen if it is environment; it gets destroyed when the script finishes or is killed. Care to explain? Thanks!

Remember there are shared hosting providers that offer you imapsync but don't do any process hiding. We at Onlime have the procfs hidepid=2 mount option in place on all shared webservers, so that's not really an issue. But other (bad) customers could sniff other's running processes if that's not the case.

And yes, leaving a file behind is never a good idea. A matter of taste, which is worse, depends on your environment.

Cheers, Pipo

Oh, so you are suggesting the risk is that someone logged in the same shared server could pick the password from the process table with ps. That makes sense.
Thank you.