diff --git a/scripts/bootstrap-to-docker.sh b/scripts/bootstrap-to-docker.sh
index a5e8ab0..653ba7b 100755
--- a/scripts/bootstrap-to-docker.sh
+++ b/scripts/bootstrap-to-docker.sh
@@ -15,7 +15,7 @@ fi
 tmpdir=${tmpdir:-"/var/tmp"}
 docker_user=${docker_user:-${USER}}
 if test -z "$archs"; then
-    case $(dpkg --print-architecture); in
+    case "$(dpkg --print-architecture)" in
         (amd64) archs="i386 amd64";;
         (*) archs=$(dpkg --print-architecture)
     esac