alive

#! /var/bin/mksh
# grab just the ip address from ping output, then sort|uniq
set -A uniquehosts $(ping -nc 3 broadcast | sed -n '/icmp_seq=/{
s/^[0-9]* bytes from //
s/: icmp_seq=.*$//
p
}' | sort | uniq )
# for each ip, lookup hostname from /etc/hosts
for host in  ${uniquehosts[@]}
do
  hostname=$(awk \/^${host}'[ \t]/{ print $2 }' /etc/hosts )
  if [[ -z $hostname ]]; then
   echo $host
  else
   echo $hostname
  fi
done