ddns-confgen: invalid argument --
Usage:
 ddns-confgen [-a alg] [-k keyname] [-q] [-s name | -z zone]
  -a alg:        algorithm (default hmac-sha256)
  -k keyname:    name of the key as it will be used in named.conf
  -s name:       domain name to be updated using the created key
  -z zone:       name of the zone as it will be used in named.conf
  -q:            quiet mode: print the key, with no explanatory text