diff --git a/lib/pry/cli.rb b/lib/pry/cli.rb
index 56ba1981..afb86d45 100644
--- a/lib/pry/cli.rb
+++ b/lib/pry/cli.rb
@@ -52,7 +52,7 @@ class Pry
         self.option_processors = nil
       end
 
-      def parse_options(args=ARGV)
+      def parse_options(args=ARGV.dup)
         raise NoOptionsError, "No command line options defined! Use Pry::CLI.add_options to add command line options." if !options
 
         opts = Slop.parse(args, :help => true, :multiple_switches => false, &options)