diff --git a/build-tools/build-docker-images/build-stx-base.sh b/build-tools/build-docker-images/build-stx-base.sh
index 76bd8ca8..1582aac7 100755
--- a/build-tools/build-docker-images/build-stx-base.sh
+++ b/build-tools/build-docker-images/build-stx-base.sh
@@ -154,7 +154,7 @@ while true; do
             shift 2
             ;;
         --repo)
-            REPO_LIST+=($2)
+            REPO_LIST+=("$2")
             shift 2
             ;;
         --local)