build transaction without giving fee, is it possible? --change-address

Question

i have seen in forum.cardano someone giving the parameter --change-address and explaing that we dont have to calculate the fee.

does anyone can verify this for mainnet and this current moment, if that works?

also my understanding is, we will give input, then the output to the recipient(s) and the rest goes to my address (in --change-address)

for the example below, we see a mint Token. can we use --change-address for any transaction? also only to send ADA?

cardano-cli transaction build
--mainnet
--alonzo-era
--tx-in $txhash#$txix
--tx-out $address+$output+"$tokenamount $policyid.$tokenname"
--change-address $address
--mint="$tokenamount $policyid.$tokenname"
--minting-script-file $script
--metadata-json-file metadata.json
--invalid-hereafter $slotnumber
--witness-override 2
--out-file matx.raw

do we need also the "--alonzo-era " ?

Answer 1

Using --change-address will send all the remaining balances to the specified address. It also includes tokens other than adas. Just keep in mind that there is a min amount of ada required for each utxo.

Yes, you need --alonzo-era.

There are some mistakes in your build command. You are missing following options.

--tx-in-collateral before the first --tx-out

--mint-redeemer-value or --mint-redeemer-file after --mint-script-file

--mint-script-file, not --minting-script-file