# File lib/specinfra/command/freebsd/base/interface.rb, line 26
    def check_has_ipv6_address(interface, ip_address)
      ip_address = ip_address.dup
      (ip_address, prefixlen) = ip_address.split(/\//)
      ip_address.downcase!
      if ip_address =~ /^fe80::/i
        # link local needs the scope (interface) appended
        ip_address << "%#{interface}"
      end
      unless prefixlen.to_s.empty?
        # append prefixlen
        ip_address << " prefixlen #{prefixlen}"
      else
        ip_address << " "
      end
      "ifconfig #{interface} inet6 | grep 'inet6 #{ip_address}'"
    end