def read_keys_file(path)
      return [] unless File.exists?(path)
      File.readlines(path).map! { |l| l.chomp.strip }
    end
def read_keys_file(path)
      return [] unless File.exists?(path)
      File.readlines(path).map! { |l| l.chomp.strip }
    end
=== OS specific methods
 Reads specified keys file if it exists

 == Parameters
 @param [String] path to authorized_keys file

 == Return
 @return [Array<String>] list of lines of authorized_keys file