diff --git a/poky/scripts/sstate-diff-machines.sh b/poky/scripts/sstate-diff-machines.sh
index 27c6a33..1d721eb 100755
--- a/poky/scripts/sstate-diff-machines.sh
+++ b/poky/scripts/sstate-diff-machines.sh
@@ -1,5 +1,7 @@
 #!/bin/bash
-
+#
+# SPDX-License-Identifier: GPL-2.0-only
+#
 # Used to compare sstate checksums between MACHINES.
 # Execute script and compare generated list.M files.
 # Using bash to have PIPESTATUS variable.