Shell script to scan a range of IP addresses. USAGE: ./pingscan 192.168.1.

pingscan.sh

#!/bin/sh

: ${1?"Usage: $0 ip subnet to scan. eg '192.168.1.'"}

subnet=$1
for addr in `seq 0 1 255 `; do
#   ( echo $subnet$addr)
( ping -c 3 -t 5 $subnet$addr > /dev/null && echo $subnet$addr is Alive ) &
done

It's going to be better if you add this two lines of code at the end of the script.

wait
echo 'scan done'