diff --git a/shell/docker-build.sh b/shell/docker-build.sh
index c8dbd70..7990784 100644
--- a/shell/docker-build.sh
+++ b/shell/docker-build.sh
@@ -6,11 +6,11 @@
 FULL_DATE=`date +'%Y%m%dT%H%M%S'`
 IMAGE_VERSION=`xmlstarlet sel -N "x=http://maven.apache.org/POM/4.0.0" -t -v "/x:project/x:version" pom.xml | cut -c1-5`
 
-case $DOCKERREGISTRY in
-   '$DOCKER_REGISTRY:10004') DOCKER_TAG="$IMAGE_VERSION"-STAGING-"$FULL_DATE"Z
+case "$DOCKERREGISTRY" in
+   "$DOCKER_REGISTRY:10004") DOCKER_TAG="$IMAGE_VERSION"-STAGING-"$FULL_DATE"Z
       echo "Using tag $DOCKER_TAG"
       ;;
-   '$DOCKER_REGISTRY:10003') DOCKER_TAG="$IMAGE_VERSION"-SNAPSHOT-"$FULL_DATE"Z
+   "$DOCKER_REGISTRY:10003") DOCKER_TAG="$IMAGE_VERSION"-SNAPSHOT-"$FULL_DATE"Z
       echo "Using tag $DOCKER_TAG"
       ;;
 esac