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
and I have one in base58 given by bitcoin-cli dumpprivkey:
bitcoin-cli dumpprivkey 154G5oUywHU3pESNy4oBBpkmAGqRZiYxBk
How do I get it in hex in the right format?