1 files changed, 1 insertions, 0 deletions
diff --git a/diff-tree.c b/diff-tree.c
index 3c8838582..6c98e62ad 100644
--- a/diff-tree.c
+++ b/diff-tree.c
@@ -507,6 +507,7 @@ int main(int argc, const char **argv)
 		}
 		if (!strncmp(arg, "--pretty", 8)) {
 			verbose_header = 1;
+			header_prefix = "diff-tree ";
 			commit_format = get_commit_format(arg+8);
 			continue;
 		}