diff --git a/common.sh b/common.sh
old mode 100644
new mode 100755
index 2a21e0a..fe573f6
--- a/common.sh
+++ b/common.sh
@@ -10,7 +10,7 @@ onMac() {
 
 filesize() {
   if onMac; then
-    stat -f%z $1
+    stat -f "%z" $1
   else
     stat --printf="%s" $1
   fi