Show your public IP from BASH command line using only default/barebones commands (route, ip and host).

myip.bash

#!/bin/bash
# Brady Shea - APR 2024
# No 'dnsutils' (dig/nslookup) package needed for this command.
# Make sure these are in your path.
# They usually reside in /usr/sbin or /usr/bin if you need to set manually:
route=$(command -v route)
ip=$(command -v ip)
host=$(command -v host)

printf "Gateway:\n"; $route | grep "^default" | cut -d " " -f 10
printf "Private:\n"; $ip -4 -o ad | grep "brd "| cut -d " " -f 7
printf "Public:\n"; $host -4 -t a myip.opendns.com resolver1.opendns.com | grep "myip.opendns.com has"| cut -d " " -f 4

# If you have 'dig' you could also use this for public:
# > printf "Public:\n"; dig +short myip.opendns.com @resolver1.opendns.com
# (or) Quoted public:
# dig TXT +short o-o.myaddr.l.google.com @ns1.google.com

output_example.txt

Gateway:
192.168.1.1
Private:
192.168.1.101/24
Public:
199.199.199.199

Instructions:

Copy the script to somewhere in your path and make it executable.

cp ./myip.bash ~/myip && chmod 750 ~/myip

Then simply run it by typing 'myip' on the command line from any directory.