#!/bin/bash
########################################################################
# Author: Fred (support@qo-op.com)
# Version: 0.3
# License: AGPL-3.0 (https://choosealicense.com/licenses/agpl-3.0/)
########################################################################
{ # Full reading before execution !
# echo '
# 
#     __  ___                                       _     ___ 
#    /  |/  /_  __   ____  ____ _____ ___  ___     (_)___/__ \
#   / /|_/ / / / /  / __ \/ __ `/ __ `__ \/ _ \   / / ___// _/
#  / /  / / /_/ /  / / / / /_/ / / / / / /  __/  / (__  )/_/  
# /_/  /_/\__, /  /_/ /_/\__,_/_/ /_/ /_/\___/  /_/____/(_)   
#        /____/                                               
# 
# ' | lolcat
MY_PATH="`dirname \"$0\"`"              # relative
MY_PATH="`( cd \"$MY_PATH\" && pwd )`"  # absolutized and normalized
ME="${0##*/}"

# GNU DEBIAN Core install extension
[[ ! $(which nslookup) ]] && sudo apt-get update && sudo apt-get install dnsutils -y

# What I am doing:
export myIP=$(hostname -I | awk '{print $1}')
# Check if IP is from reserved LAN addresses
export isLAN=$(echo $myIP | grep -E "/(^127\.)|(^192\.168\.)|(^10\.)|(^172\.1[6-9]\.)|(^172\.2[0-9]\.)|(^172\.3[0-1]\.)|(^::1$)|(^[fF][cCdD])/")
# Find 1st route gateway
export myRouter=$(sudo route -n | head -n 3 | tail -n 1 | awk '{print $2}')
# Ask to the router its name (BOX DNS or system defined)
[[ $isLAN ]] && export NODENAME=$(sudo nslookup $myIP $myRouter | head -n 1 | awk -F ' = ' '{print $2}' | sed 's/\.[^.]*$//') \
|| export NODENAME=$(sudo nslookup $myIP | head -n 1 | awk -F ' = ' '{print $2}' | sed 's/\.[^.]*$//')

# I can tell
echo "$NODENAME"

} # Full reading before execution !