Counts IPv4 addresses in MaxMind's GeoLite2 database

countIP.sh

#!/bin/bash

###    Counts IPv4 addresses in MaxMind's GeoLite2 database      ###
### It does the summation of how many IPs are in each CIDR range ###
### https://dev.maxmind.com/geoip/geolite2-free-geolocation-data ###

echo "Warning: the execution of this script can take many hours!"

param=0       # $param contains the summation
skip='true'   # we use $skip to skip the first row, containing the CSV header row
file="GeoLite2-City-Blocks-IPv4.csv" # this is the database, it must be in the same folder as the script

while read line; do
    if [[ $skip == 'true' ]]; then
        skip='false';
        continue; # we skip the CSV header row
    fi;
    num=`echo "${line}" | awk -F / '{ count[$2]++ } END { for (mask in count) total+=count[mask]*2^(32-mask); print total }'`
    #echo "IPs added: $num";   # number of IPs in the CIDR; we can uncomment for debugging
    param=$(bc <<< "$param + $num")
    #echo "Total IPs: $param"  # summation; we can uncomment for debugging
done < "${file}"

echo "Total IPv4 addresses: $param"