diff --git a/terraform_validate_no_variables.sh b/terraform_validate_no_variables.sh
index 1ecc9b4..8aaa140 100755
--- a/terraform_validate_no_variables.sh
+++ b/terraform_validate_no_variables.sh
@@ -13,7 +13,7 @@ for path_uniq in $(echo "${paths[*]}" | tr ' ' '\n' | sort -u); do
   pushd "$path_uniq" > /dev/null
   terraform validate -check-variables=false
 
-  if [[ $? != 0 ]]; then
+  if [[ "$?" -ne 0 ]]; then
     echo
     echo "Failed path: $path_uniq"
     echo "================================"
diff --git a/terraform_validate_with_variables.sh b/terraform_validate_with_variables.sh
index c24d841..a3de4a9 100755
--- a/terraform_validate_with_variables.sh
+++ b/terraform_validate_with_variables.sh
@@ -13,7 +13,7 @@ for path_uniq in $(echo "${paths[*]}" | tr ' ' '\n' | sort -u); do
   pushd "$path_uniq" > /dev/null
   terraform validate -check-variables=true
 
-  if [[ $? != 0 ]]; then
+  if [[ "$?" -ne 0 ]]; then
     echo
     echo "Failed path: $path_uniq"
     echo "================================"