hexdump

# offsets, hex and ascii bytestrings
hexdump -C [file]

# 16 hex bytes pr line
hexdump -e '16/1 "%02x " "\n"' [file]

Examples

# base64-encoded binary 256-bit groups (eg. sha256) to hexbytes
echo -n <b64 data> | base64 -d | hexdump -e '32/1 "%02x" "\n"'