How to Validate IP address range (Shell Scripting) - bash

Question

I'm trying to figure out how to edit this script so it will validate an IP range instead of just one IP, i.e. 192.168.1.0/24.
echo "Target IP Address range or specific IP: "
read IPaddr
#IPv4 Validation
is_ip(){
local ip=$1
if expr "$ip" : '[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*$' >/dev/null;then
for i in 1 2 3 4;do
if [ $(echo "$ip" | cut -d. -f$i) -gt 255 ];then
return 1
fi
done
return 0
else
return 1
fi
}
#Test User-inputted IPv4 Address
is_ip "$IPaddr"
if [[ $? -eq 0 ]]; then
echo "Valid IP address/range"
else
echo "Invalid IPv4"
exit 6
fi

Answer 1

This script seems to do what you want if I've understood your question properly.
#!/bin/bash
locInput="$1"
locIP=${locInput%\/*}
if [[ $locInput = #(*/*) ]];then
locRange=${locInput#*\/}
fi
function is_ip
{
if [[ $locIP == ?([0-9])+([0-9])\.?([0-9])+([0-9])\.?([0-9])+([0-9])\.?([0-9])+([0-9]) ]]; then
locVerif=(${locIP//./ })
for i in ${locVerif[*]}; do
if [[ $i -lt 0 || $i -gt 255 ]]; then
return 1
fi
done
if [[ -n $locRange && ($locRange -lt 0 || $locRange -gt 31) ]]; then
return 1
fi
return 0
else
return 1
fi
}
is_ip
if [[ $? -eq 1 ]]; then
echo "Wrong IP/Range"
else
echo "Good IP/Range"
fi
Hope it can help.