add bash git/pgp/plaintext example

README.md

@@ -66,6 +66,23 @@ they appear in all capitals, as shown here.
 - sig_type: (required) signature type (webauthn, pgp, etc)
 - signature: (required) actual ascii armored signature payload
 
+## Examples
+
+### Bash: Git and pgp with plaintext review
+```
+local -r review_body="LGTM"
+local -r review_hash="$(printf $review_body | openssl sha256 | awk '{print $2}')"
+local -r vcs_ref="$(git rev-parse HEAD)"
+local -r tree_hash="$(git rev-parse 'HEAD^{tree}')"
+local -r sig_body="sig:v0:$vcs_ref:$tree_hash:$review_hash:pgp"
+local -r sig=$(\
+    printf "%s" "$body" \
+    | gpg --detach-sign  \
+    | openssl base64 -A \
+)
+printf "%s" "$sig_body:$review_body:$sig"
+```
+
 ## Background
 
 TODO