needs some hacking…

1) for me, at least, the arp command is /usr/sbin/arp

2) it might be better to just replace everything from the gta= line to the ttl= line with something like:

ttl=$( /usr/sbin/arp -n | grep ether | awk ‘{ print $3 }’ | sort | uniq -d | wc -l )

This is 10 times faster (on my relatively small net), but only counts 1 for each mac that appears two or more times. If you want a MAC appearing three times to give a count of two, try:

gta=`/usr/sbin/arp -n | grep ether | awk ‘{ print $3 }’`
gtl=`echo “$gta” | sort -u | wc -l`
tot=`echo “$gta” | wc -l`
ttl=$(( $tot – $gtl ))