diff --git a/.drone.yml b/.drone.yml
index 37369db..99dd80a 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -9,7 +9,7 @@ steps:
     environment:
       CUPSRELEASE: "${DRONE_TAG##v}"
     commands:
-      - [ -z "$CUPSRELEASE" ] && CUPSRELEASE=2.2.10
+      - '[ -z "$CUPSRELEASE" ] && CUPSRELEASE=2.2.10'
       - wget https://github.com/apple/cups/releases/download/v$CUPSRELEASE/cups-$CUPSRELEASE-source.tar.gz
       - mkdir ./rpms
       - rpmbuild -ta --define "_rpmdir $(pwd)/rpms" --without libusb1 cups-$CUPSRELEASE-source.tar.gz