diff --git a/branches.go b/branches.go
index 2788300..4fa85b8 100644
--- a/branches.go
+++ b/branches.go
@@ -64,6 +64,18 @@ func (repo *Repo) GetTagHash(t string) string {
 	return result.Stdout[0]
 }
 
+// lookup a hash from a tag with 'git rev-list'
+func (repo *Repo) GetBranchDifferences(from string, to string) []string {
+	// git rev-list -n 1 v0.0.66
+	cmd := []string{"git", "rev-list", to + "..." + from}
+	result, _ := repo.RunStrict(cmd)
+	// log.Info("getLastTagVersion()", result.Stdout)
+
+	// tmp := strings.TrimSpace(strings.Join(result.Stdout, "\n"))
+	// return shell.SplitNewLines(tmp)
+	return result.Stdout
+}
+
 // deletes the devel local branch if it is a subset of the remote devel branch
 func (repo *Repo) DeleteLocalDevelBranch() error {
 	branch := repo.GetDevelBranchName()