asn.sh

#!/bin/bash

if [ $# -eq 0 ]; then
    echo "You must provide at least one ASN (multiple should be separated by space)."
    exit 0
fi
result=""
re='^[0-9]+$'   # simple regex to make sure that each ASN is a number
for arg in "$@"; do
    if [[ $arg =~ $re ]]; then
        temp=$(whois -h whois.radb.net -- "-i origin AS${arg}" | grep -Eo "([0-9.]+){4}/[0-9]+")
        result="$result $temp"
    fi
done
for res in $result; do
    echo -e "  deny $res;"
done