Use restored fork of amino decoder instead, much faster and less jank: https://github.com/daimeng/amino-decoder/
Run on a single Tx base64 string:
docker run --rm rmdec/terra-decoder:0.3 unmarshalTx TX_STRING
Running with exec:
docker run -it --rm --entrypoint /bin/sh -d --name unmarshaller rmdec/terra-decoder:0.3
docker exec unmarshaller ./entrypoint.sh unmarshalTx TX_STRING TX_STRING2
docker stop unmarshaller