diff --git a/debian/check-ruby-syntax.sh b/debian/check-ruby-syntax.sh
index b40efff1ce..c2c4b9068a 100644
--- a/debian/check-ruby-syntax.sh
+++ b/debian/check-ruby-syntax.sh
@@ -1 +1,4 @@
+# For whole tree
 find . -name \*.rb -exec ruby -wc {} \; 2>&1 | grep error
+# For changed files
+for i in `git diff --name-only debian/13.1.1-1 HEAD | grep \.rb\$`; do ruby -wc $i; done