ipcalc where have you been hiding

Somehow I've lived this long and never stumbled upon ipcalc.  It made scripting a secondary interface and route file very easy.

I wanted to be able to dynamically configure /etc/sysconfig/network-scripts/route-eth1 during boot.  I was working on my own convoluted sed script to get the right values, but ipcalc was already there and simplified my work.

Normally, I'd put something like:
ADDRESS0=6.6.1.0
NETMASK0=255.255.255.0
GATEWAY0=6.6.1.1

But in Amazon, some of these values can vary and for puppet to be able to distribute to any of my environments across my AZs:

VPC_CIDR_URI="http://169.254.169.254/latest/meta-data/network/interfaces/macs/${ETH0_MAC}/vpc-ipv4-cidr-block"
SUBNET_CIDR_URI="http://169.254.169.254/latest/meta-data/network/interfaces/macs/${ETH1_MAC}/subnet-ipv4-cidr-block"
ADDRESS0=`ipcalc -n ${VPC_CIDR_RANGE} | sed -e's/^NETWORK/ADDRESS0/'`
NETMASK0=`ipcalc -m ${VPC_CIDR_RANGE} | sed -e's/^NETMASK/NETMASK0/'`
GATEWAY0=`ipcalc -n ${SUBNET_CIDR_RANGE} | sed -e's/^NETWORK/GATEWAY0/;s/\.[0-9][0-9]*$/.1/;'`

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