vyos@vyos# set interfaces ethernet eth1 address "a valid IP address, I swear!"

  Error: wrong number of arguments, one argument required!
  Usage: ipaddrcheck <OPTIONS> [STRING]
  Address checking options:
    --is-valid                 Check if STRING is a valid IPv4 or IPv6 address
                                 with or without prefix length
    --is-any-cidr              Check if STRING is a valid IPv4 or IPv6 address
                                 with prefix length