diff --git a/lib/ginseng/command_line.rb b/lib/ginseng/command_line.rb
index 674bf82..3dc07d6 100644
--- a/lib/ginseng/command_line.rb
+++ b/lib/ginseng/command_line.rb
@@ -30,7 +30,7 @@ def env=(env)
     end
 
     def to_s
-      return args.map(&:to_s).map(&:shellescape).join(' ')
+      return args.map {|v| v.to_s.shellescape}.join(' ')
     end
 
     def exec