#!/bin/bash

# take MAC as argument and print modified EUI-64 for IPv6 address generation.

IFS=':' read -a mac <<<"$1"
mac[0]=`printf '%x' $((0x${mac[0]} | 2))` # set universal bit
echo "${mac[0],,}${mac[1],,}:${mac[2],,}ff:fe${mac[3],,}:${mac[4],,}${mac[5],,}"