diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index c22c528..3b0127a 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -51,8 +51,8 @@ why2-core-test:
     - sudo $CONFIGURE # Preparation
     - make install BYPASS_CHECK=true # Install WHY2
     - make test_core # Build WHY2 Test
-    - $GDB $CORE_OUTPUT # Test Lib
-    - $GDB $CORE_APP # Test App
+    - ${GDB} $CORE_OUTPUT # Test Lib
+    - ${GDB} $CORE_APP # Test App
     - $VALGRIND $CORE_OUTPUT # Test Lib by Valgrind
 
 why2-logger-test:
@@ -65,8 +65,8 @@ why2-logger-test:
     - sudo $CONFIGURE # Preparation
     - make install BYPASS_CHECK=true # Install WHY2
     - make test_logger # Build WHY2 Test
-    - $GDB $LOGGER_OUTPUT # Test Lib
-    - $GDB $LOGGER_APP # Test App
+    - ${GDB} $LOGGER_OUTPUT # Test Lib
+    - ${GDB} $LOGGER_APP # Test App
     - $VALGRIND $LOGGER_OUTPUT # Test Lib by Valgrind
 
 why2-project: