Unused/untested function for converting hostnames to ip and the reverse

host2ip

host2ip() {
  # If $1 is missing, print brief usage
  if [[ -n "$1" ]]; then
    printf '%s\n' "Usage: host2ip [hostname|ip.add.re.ss]"
    return 1
  # If $1 appears to be a node name, figure out its IP
  elif [[ "$1" =~ '^[a-zA-Z]$' ]]; then
    host -4 -W 1 "$1" | awk '{print $4}'
  # If $1 appears to be an IP address, try to figure the reverse  
  elif [[ "$1" =~ '^((25[0-5]|2[0-4][0-9]|[01][0-9][0-9]|[0-9]{1,2})[.]){3}(25[0-5]|2[0-4][0-9]|[01][0-9][0-9]|[0-9]{1,2})$' ]]; then
    host -4 -W 1 "$1" | awk '{print $4}' | cut -d '.' -f1
  else
    printf '%s\n' "host2ip could not determine what is meant by: $1"
    return 1
  fi
}