diff --git a/git-annex-update-index-modified b/git-annex-update-index-modified
new file mode 100755
index 0000000..fb772ea
--- /dev/null
+++ b/git-annex-update-index-modified
@@ -0,0 +1,12 @@
+#!/usr/bin/env python3
+import subprocess
+import sys
+
+out = subprocess.check_output(["git", "status", "-zs"])
+for line in out.split(b"\0"):
+    line = line.decode("UTF-8")
+    if len(line) >= 2 and line[1] == "M":
+        pathname = line[3:]
+        print(pathname)
+        # XXX stages files...
+        subprocess.run(["git", "update-index", "--refresh", pathname])