# File lib/chef/provider/env.rb, line 123
      def action_modify
        if @key_exists
          if compare_value
            modify_env
            @new_resource.updated_by_last_action(true)
            Chef::Log.info("Modified #{@new_resource}")
          end
        else
          raise Chef::Exceptions::Env, "Cannot modify #{@new_resource} - key does not exist!"
        end
      end