diff --git a/dokku b/dokku
index 802e88538..ef1e28447 100755
--- a/dokku
+++ b/dokku
@@ -69,7 +69,7 @@ case "$1" in
     DOKKU_SCALE_FILE="$DOKKU_ROOT/$APP/DOKKU_SCALE"
     oldids=$(get_app_container_ids $APP)
 
-    while read line || [ -n "$line" ]
+    while read line || [[ -n "$line" ]]
     do
       TRIM=${line%#*}
       PROC_TYPE=${TRIM%%=*}