diff --git a/mariadb-103.sh b/mariadb-103.sh
index ff22b3b..659c66b 100644
--- a/mariadb-103.sh
+++ b/mariadb-103.sh
@@ -14,7 +14,7 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
-set -e
+set -eu
 
 output(){
     printf '\e[1;34m%-6s\e[m\n' "${@}"
diff --git a/mariadb-104-legacy.sh b/mariadb-104-legacy.sh
index 0ca6c54..ccd4902 100644
--- a/mariadb-104-legacy.sh
+++ b/mariadb-104-legacy.sh
@@ -14,7 +14,7 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
-set -e
+set -eu
 
 output(){
     printf '\e[1;34m%-6s\e[m\n' "${@}"
diff --git a/mariadb-104.sh b/mariadb-104.sh
index 37639ce..a18bee8 100644
--- a/mariadb-104.sh
+++ b/mariadb-104.sh
@@ -14,7 +14,7 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
-set -e
+set -eu
 
 output(){
     printf '\e[1;34m%-6s\e[m\n' "${@}"