How can I write a Linux bash script that tells me which computers are ON in my LAN?

Question

How can I write a Linux Bash script that tells me which computers are ON in my LAN?

It would help if I could give it a range of IP addresses as input.

Answer 1

Just for fun, here's an alternate

     #!/bin/bash
     nmap -sP 192.168.1.0/24 > /dev/null 2>&1 && arp -an | grep -v incomplete | awk '{print$2}' | sed -e s,\(,, | sed -e s,\),,