#!/bin/bash
#
#script to change MAC ("hardware address")
#Pete Nesbitt Sept 2005

# prompt for change or rest
  # if new, prompt for new mac
  # store existing hwadress


# get confirmation to continue or exit program
CHANGE_MAC="Y"
 echo ""
 echo ""
 printf "   =>  Change MAC Address? (N/n/R/r to Reset to Old Mac): [${CHANGE_MAC}]"
   read CHANGE_MAC
   if [ "$CHANGE_MAC" = "" ]; then
      CHANGE_MAC="Y"
   fi
   if [ "$CHANGE_MAC" = "Y" ] || [ "$CHANGE_MAC" = "y" ] ; then
      echo ""

      # Save original MAC (save to file for next run, tmp is okay as system resets anyway on reboot)
      OLD_MAC="`/sbin/ifconfig|grep eth0|awk '{print $5}'`"
      echo $OLD_MAC > /tmp/old_mac.txt

      # save the default route
      DEFAULT_ROUTE="`/sbin/route -n|grep UG|awk '{print $2}'`"
      echo $DEFAULT_ROUTE > /tmp/default_route.txt

      # Get new MAC
      NEW_MAC=""
      printf "   =>  Enter NEW MAC Address? (aa:bb:cc:dd:ee:ff): [${NEW_MAC}]"
      read NEW_MAC
      /sbin/ifconfig eth0 down
      /sbin/ifconfig eth0 hw ether $NEW_MAC
      /sbin/ifconfig eth0 up
      # reinstate default route
      /sbin/route add default gw ${DEFAULT_ROUTE} dev eth0

   else # reset old MAC
        # now we will need to read data from files, not vars
      RESET_MAC="Y"
      echo ""
      echo " Reset MAC to original?"
      echo ""
      printf "   => Reset to original MAC Address?: [${RESET_MAC}]"
      read RESET_MAC
         if [ "$RESET_MAC" = "" ]; then
            RESET_MAC="Y"
         fi
         if [ "$RESET_MAC" != "Y" ] && [ "$RESET_MAC" != "y" ] ; then
            echo "Program exited by user."
            echo ""
            exit 0
         else
         /sbin/ifconfig eth0 down
         /sbin/ifconfig eth0 hw ether `cat /tmp/old_mac.txt`
         /sbin/ifconfig eth0 up
         /sbin/route add default gw `cat /tmp/default_route.txt`
         fi
   fi

echo ""
echo ""
echo "NEW ETHERNET (eth0) CONFIGURATION:"
/sbin/ifconfig eth0
echo ""
echo "ROUTING INFORMATION:"
/sbin/route -n