A bash shell script to output simple info about Wan IP Lan Ip

whatismyip.sh

#!/usr/bin/env bash

# Author: Chrish
# A simple script that queries the http://ifconfig.me and fetch the public ip. Also I wanted to add here
# the default nic, ip address and default gateway.

# if you like this script please leave a comment.
# if you do not like it please leave a comment again.

# All recommendations are welcomed.

set -o errexit;
# set -o nounset;
# set -o xtrace;

function whatismyip() {
  default_iface=$(ip route list | head --lines 1 | grep --perl-regexp --only-matching '\Keth[0-9]{1,2}|\Kenp\w{3}|\Kwlan[0-9]');
  lanip=$(ip address show dev "${default_iface}" | grep --perl-regexp --only-matching 'inet \K[\d.]+');
  default_gateway=$(ip route list | grep --perl-regexp --only-matching 'via \K[\d.]+');
  wanip=$(curl --silent ifconfig.me);
  while [ $# -gt 0 ]; do
    case "$1" in
      -v|--version)
        printf "WhatIsMyIP version 0.1\n"
        return 0;;
      -h|--help)
        printf "I need to work on a mini help\n"
        return 0;;
     esac    
  done    
  printf -- "%b\n" "DEVICE: \033[32m"${default_iface}"\033[0m";
  printf -- "%b\n" "LAN IP: \033[32m"${lanip}"\033[0m";
  printf -- "%b\n" "GATEWAY: \033[32m"${default_gateway}"\033[0m";
  printf -- "%b\n" "WAN IP: \033[32m"${wanip}"\033[0m";
  return 0;
}