ipcalc - IP Address Calculator

Usage: ipcalc [-v] [-a|b|m|n|p] ip-addr

This program, given an IP address and optional netmask, shows the address,
netmask, network and broadcast address in dotted decimal and binary form.
Additionally, the value slash-n is printed and whether it is a private internet
address according to RFC 1918.

Using command line options, the output can be reduced to a very specific piece
of information being printed to standard output. This is useful for scripting.

The mandatory argument ip-addr is an IPv4 address in dotted decimal notation,
optionally followed by a slash (/) and a netmask in CIDR or dotted decimal
notation. Examples:

ipcalc 130.60.16.123
ipcalc 130.60.16.123/24              # CIDR notation
ipcalc 130.60.16.123/255.255.255.0   # address with netmask

The option -v makes ipcalc print its version number; the other options make
ipcalc print only very specific pieces of information about ip-addr to standard
output:

-a    address in CIDR notation
-b    broadcast address
-m    netmask
-n    network address
-p    return 0 if private internet address, otherwise return 1. 

Examples:

$ ipcalc -a 130.60.16.123
130.60.16.123/16
$ ipcalc -a 130.60.16.123/255.255.255.0
130.60.16.123/24