diff --git a/tools/nixpkgs-hammer b/tools/nixpkgs-hammer
index 4d71906..a9a0d9c 100755
--- a/tools/nixpkgs-hammer
+++ b/tools/nixpkgs-hammer
@@ -224,4 +224,9 @@ if __name__ == '__main__':
 
     args = parser.parse_args()
 
-    main(args)
+    try:
+        main(args)
+    except subprocess.CalledProcessError as e:
+        print(red(subprocess.list2cmdline(e.cmd)))
+        print(f"Returned nonzero exit status {e.returncode}")
+        sys.exit(1)