diff --git a/clever.wdl b/clever.wdl
index 3dd41b3814534f0320b9e40fc343aa45555bc9ea..fb67a2a8ac1f8940d9dc792afcb37e1ed704c16d 100644
--- a/clever.wdl
+++ b/clever.wdl
@@ -13,7 +13,7 @@ task Prediction {
     
     command { 
         set -e
-        mkdir -p $(dirname ~{outputPath})
+        mkdir -p "$(dirname ~{outputPath})"
         clever \
         -T ~{threads} \
         --use_mapq \