def valid_ruby? file
      return false unless ::File.exists? file
      result = `ruby -c #{file} > /dev/null 2>&1`
      !result.size.zero?
    end
def valid_ruby? file
      return false unless ::File.exists? file
      result = `ruby -c #{file} > /dev/null 2>&1`
      !result.size.zero?
    end
true if file is valid ruby