#!/usr/bin/env bash

set -euo pipefail;

LIST_FILE="$(dirname "$0")/ipv4.txt";
TMP_FILE="$(mktemp)";

IP_REGEX='(?<!\d)\d+(\.\d+){3}(/\d+)?(?!\d)';

cat "$LIST_FILE" "$@" |
    grep --only-matching --perl-regexp "$IP_REGEX" |
    sort --version-sort |
    uniq > "$TMP_FILE";

echo "$TMP_FILE";
if diff "$LIST_FILE" "$TMP_FILE"; then
    echo "No differences found!";
    exit 0;
fi

echo "Press enter to approve changes, ^C to abort";
read;

mv "$TMP_FILE" "$LIST_FILE";