base64 encoded hash bytes
There are a number of places where you want a base64 encoded version of some kind of hash. Sometimes people wind up base64 encoding the hex string instead of the bytes, which is gross.
echo -n 'passphrase' |\
sha512sum |\
awk '{print $1}' |\
xxd -r -p |\
base64 -w 0
Replace sha512sum with the CLI hasher of your choosing, and adjust (or remove) awk as needed.