[CentOS] ip range cidr calculator

[Barry Brimer]

> I found a command-line program that did this once before, used it for a
> while and then forgot about it until right now and I'll be damned if I
> can find it again.
>
> A command line IP calculator that takes an address range and give it
> back in cidr format.
>
> I found an online one that does this here:
>
> http://www.ipaddresslocation.org/subnet-mask-calculator.php
>
> But I would prefer to have the commandline one back again.
>
> Does anyone know what it's called and where it can be found?

I like the one at <http://jodies.de/ipcalc-archive/ipcalc-0.41/ipcalc> 
which also gives Cisco wildcard masks as well as all the other useful 
things.