diff --git a/scripts/format-check.sh b/scripts/format-check.sh
index cdc3418..a1ba3b9 100755
--- a/scripts/format-check.sh
+++ b/scripts/format-check.sh
@@ -4,7 +4,7 @@ wget https://llvm.org/svn/llvm-project/cfe/trunk/tools/clang-format/git-clang-fo
 chmod +x git-clang-format
 
 CLANG_FORMAT_OUTPUT=$(./git-clang-format HEAD^ HEAD --diff)
-if [[ ! $CLANG_FORMAT_OUTPUT == "no modified files to format" ]]; then
+if [[ ! ${CLANG_FORMAT_OUTPUT} == "no modified files to format" ]] && [[ ! -z ${CLANG_FORMAT_OUTPUT} ]]; then
   echo "Failed clang format check:"
   echo "${CLANG_FORMAT_OUTPUT}"
   exit 1