# File lib/specinfra/command/base/file.rb, line 58
    def check_contains_within(file, expected_pattern, from=nil, to=nil)
      from ||= '1'
      to ||= '$'
      sed = "sed -n #{escape(from)},#{escape(to)}p #{escape(file)}"
      sed += " | sed -n 1,#{escape(to)}p" if from != '1' and to != '$'
      checker_with_regexp = check_contains_with_regexp("-", expected_pattern)
      checker_with_fixed = check_contains_with_fixed_strings("-", expected_pattern)
      "#{sed} | #{checker_with_regexp} || #{sed} | #{checker_with_fixed}"
    end