Update `netexp` script

[devlinjunker]

Want to see as much info about the hosts as possible

after arp -a, we should loop through each line and call nmap if installed and add info we can gleam from this.

Example call and output

> sudo nmap -sn 192.168.0.13
Starting Nmap 7.91 ( https://nmap.org ) at 2021-11-10 18:59 PST
Nmap scan report for 192.168.0.13
Host is up (0.077s latency).
MAC Address: EC:8E:B5:81:5B:4D (Hewlett Packard)
Nmap done: 1 IP address (1 host up) scanned in 0.16 seconds

Notes:

• Needed to install nmap with MacPorts on OSX
• https://askubuntu.com/questions/126467/how-to-find-a-computer-name-in-a-lan-from-the-ip-address
• More about arp command: https://www.geeksforgeeks.org/arp-command-in-linux-with-examples/