diff --git a/gravity.sh b/gravity.sh
index 6fe9be06..015764ac 100755
--- a/gravity.sh
+++ b/gravity.sh
@@ -340,11 +340,11 @@ gravity_ParseFileIntoDomains() {
     # 3) Remove lines containing "#" or "/"
     # 4) Remove leading tabs, spaces, etc.
     # 5) Delete lines not matching domain names
-    < ${source} tr -d '\r' | \
+    < "${source}" tr -d '\r' | \
     tr '[:upper:]' '[:lower:]' | \
     sed -r '/(\/|#).*$/d' | \
     sed -r 's/^.*\s+//g' | \
-    sed -r '/([^\.]+\.)+[^\.]{2,}/!d' >  ${destination}
+    sed -r '/([^\.]+\.)+[^\.]{2,}/!d' >  "${destination}"
     return 0
   fi