diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f695bac..2c0d8ae 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -14,9 +14,8 @@ before_script:
   script:
     # Hack to set an array in /bin/sh
     # http://unix.stackexchange.com/a/137571
-    - set $CI_BUILD_NAME
-    - export JOB=$(printf '%s\n' "$1")
-    - docker build -f "Dockerfile.$JOB" .
+    - set -- $CI_BUILD_NAME
+    - docker build -f "Dockerfile.$1" .
   except:
     - master