# File lib/specinfra/command/darwin/base/package.rb, line 3
    def check_is_installed(package, version=nil)
      escaped_package = escape(File.basename(package))
      if version
        cmd = %Q[brew info #{escaped_package} | grep -E "^$(brew --prefix)/Cellar/#{escaped_package}/#{escape(version)}"]
      else
        cmd = "#{brew_list} | grep -E '^#{escaped_package}$'"
      end
      cmd
    end