How to get the private key in hex from the output of dumpprivkey I am trying to create raw transactions according to the excellent answer of runeks here:
How to redeem a basic Tx?

But there he starts with a private key in hex format
18E14A7B6A307F426A94F8114701E7C8E774E7F9A47E2C2035DB29A206321725

and I have one in base58 given by bitcoin-cli dumpprivkey:

bitcoin-cli dumpprivkey 154G5oUywHU3pESNy4oBBpkmAGqRZiYxBk
KzRVLwCuCi2tH2PpSNZnwUqPwg6gaqXAM2LWobUurzAsNdC5JesE

How do I get it in hex in the right format?
OK, I managed to do it with the excellent bitcoin-tool by matja
https://github.com/matja/bitcoin-tool

git clone https://github.com/matja/bitcoin-tool.git

cd bitcoin-tool

make test

./bitcoin-tool --input-type private-key-wif --input-format base58check --output-type private-key --output-format hex --network bitcoin  --input "KzRVLwCuCi2tH2PpSNZnwUqPwg6gaqXAM2LWobUurzAsNdC5JesE"

which gave me 
5f92519eef7ec4e37cbcd25f9ba4a82e5acf9a8cd274d4d3aa3aa727fd7b6969

as a result.