Find all IP addresses on subnet with mac address

#!/usr/bin/env bash
while read line
do
    vendorMac=`echo $line | awk ' { print gensub(/^(.+:.+:.+):/, "\\\1", "g", $2); } '`
    vendor=`wget -qO- http://www.macvendorlookup.com/api/v2/$vendorMac 2>/dev/null | base64 | awk ' { printf "%s", $0 } '`
    echo "$line $vendor"
done

#!/usr/bin/env bash
prefix=`ifconfig eth0 | awk '/inet addr/ { print gensub(/Bcast:(.+)\.[0-9]+$/, "\\\1", "g", $3) } '`
for i in `seq 254`; do
    ping -c1 -w1 $prefix.$i &> /dev/null && arp -n | awk ' /'$prefix'.'$i' / { print $1 " " $3 } ' &
done
wait