diff --git a/doc/reference.conf b/doc/reference.conf
index e1aa89a2..b008d0e4 100755
--- a/doc/reference.conf
+++ b/doc/reference.conf
@@ -1329,12 +1329,12 @@ general {
 	 * $ openssl x509 -outform DER < your.crt | sha1sum     (or sha256sum, or sha512sum)
 	 *
 	 * To generate a SPKI SHA-256 fingerprint, run the following:
-	 * $ openssl x509 -pubkey -noout < your.crt | grep -v 'PUBLIC KEY' | base64 -d | \
-	 *   sha256sum | awk '{ print $1 }' | sed -r -e 's/^/SPKI:SHA2-256:/'
+	 * $ openssl x509 -pubkey -noout -in your.crt | openssl pkey -pubin -outform DER | \
+	 *   sha256sum | sed -r -e 's/^/SPKI:SHA2-256:/'
 	 *
 	 * To generate a SPKI SHA-512 fingerprint, run the following:
-	 * $ openssl x509 -pubkey -noout < your.crt | grep -v 'PUBLIC KEY' | base64 -d | \
-	 *   sha512sum | awk '{ print $1 }' | sed -r -e 's/^/SPKI:SHA2-512:/'
+	 * $ openssl x509 -pubkey -noout -in your.crt | openssl pkey -pubin -outform DER | \
+	 *   sha512sum | sed -r -e 's/^/SPKI:SHA2-512:/'
 	 */
 	certfp_method = sha256;
 };