My wallet has 3 addresses. My other wallet has 5 addresses. I just want to synchronize those.
How would I do so?
Just export the private key of one wallet and import to the other.
Please explain why you want to do this?
If your goal is to consolidate the funds, just send the money from one wallet to the other.
This informal article is not about transferring funds between wallets, nor about using the 'sweep address' procedure to transfer funds from one address to another.
It is about cloning an address from one wallet into another different wallet. This address will be usable from both.
Wallets are sets of Addresses. Each Address has a balance ('amount') an id ('address'), a tag ('account'), and a private key.
In order to clone addresses between wallets you have to know the private key of source address.
BitCoinCore:
Help | Debug Window | Console
backupwallet "local file system destination\wallet.dat" # make a backup copy of your wallet (optional)
dumpwallet "local file system destination\wallet.dat.txt" # make a human readable list of your wallet. Warning: includes private keys so destroy after use
Electrum:
Wallet | Private Keys | Import | copy here the private keys of address(es) to be cloned see file wallet.dat.txt
Electrum:
Wallet | Private Keys | Export
save or copy paste to the notepad, warning: keys are prefixed with 'p2pkh:' you must ignore that prefix. Warning: includes private keys so destroy after use
BitCoinCore:
Help | Debug Window | Console
importprivkey "private_key from above" "optional_tag"
warning: After that BitCoin Core automatically rescans the whole database, this may take hours.
backupwallet "local file system destination\wallet.dat" # make a backup copy of your wallet (optional)