# File lib/specinfra/command/debian/base/package.rb, line 3
    def check_is_installed(package, version=nil)
      escaped_package = escape(package)
      if version
        cmd = "dpkg-query -f '${Status} ${Version}' -W #{escaped_package} | grep -E '^(install|hold) ok installed #{Regexp.escape(version)}$'"
      else
        cmd = "dpkg-query -f '${Status}' -W #{escaped_package} | grep -E '^(install|hold) ok installed$'"
      end
      cmd
    end