diff --git a/common/functions.sh b/common/functions.sh
index ef66051..7f64e0e 100644
--- a/common/functions.sh
+++ b/common/functions.sh
@@ -79,7 +79,7 @@ get_system_used_space() {
 }
 
 human_readable_bytes() {
-  local spacebytes=$1
+  local spacebytes="$1"
   printf "$COL_YELLOW" "test $1 test"
   spacekb=`expr "$spacebytes" / 1024`
   spacemb=`expr "$spacebytes" / 1024 / 1024`