MAC swap

[Hawaiisnowstorm]

Okay, this is gona a few questions in it.
I wrote a shell script that scrambles the last 3 sets of numbers in a mac address when its told to run - I had some free time and thought why not. Currently it swaps the address with eth0 and runs when I click on it to run.


#!/bin/bash
ifconfig eth0 down
MA=`ifconfig | grep HWaddr | cut -f 11- -d " " | cut -f -3 -d :`
NumberGen()
{
number=$[($RANDOM % 15 )]
case $number in
10 )
XF=A;;
11)
XF=B;;
12)
XF=C;;
13)
XF=D;;
14)
XF=E;;
15)
XF=F;;
*)
XF=$number
esac
return
}
NumberGen ; A1=$XF
sleep 1;
NumberGen ; A2=$XF
sleep 1;
NumberGen ; B1=$XF
sleep 1;
NumberGen ; B2=$XF
sleep 1;
NumberGen ; C1=$XF
sleep 1;
NumberGen ; C2=$XF

ifconfig eth0 hw ether
echo $MA:$A1$A2\:$B1$B2\:$C1$C2
ifconfig eth0 up


How would I tell it to edit to pull the current eth that is running to scramble it, and/or how would I tell it to run at start up and change the mac address on all eths before the nic is turned on

Thanks!:D

[Hawaiisnowstorm]

bump bump .. any one?