    def build(command, params = nil)
      return command.to_s if params.nil? || params.empty?
      "#{command} #{assemble_params(sanitize(params))}"
    end
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.