ipcalc is a terminal tool that lets you validate an IP address. This proves useful to me as I have scripts that automate certain remote tasks given an IP address. Instead of trusting that an argument passed is a valid IP, why not check it?

First the script would need to check if ipcalc exists.

if ! command -v ipcalc > /dev/null ; then
    echo "ipcalc not found. Exiting..."
    exit 1
fi

Now for this example, we’ll validate an IP address stored in the variable $IP.

if ! ipcalc -cs "$IP" ; then
    echo "Invalid IP Address"
    exit 1
fi