This is a tools that is useful if you have a large list of ip-addresses and you want to find out if there are any virtual hosts which shares the same ips, or just generally what applications are hosted on the ips.
Bing, nowadays Azure could API, allows users to do searches on IP-adresses. This little tool does just that, sifting through the searchresults giving you the urls. Basic usage:
$ echo "18.104.22.168" | python ipsearch.py -b bkey.txt 22.214.171.124 : http://martin.swende.se 126.96.36.199 : http://www.swende.se
More common usage:
$ cat big_addr_list.txt | python ipsearch.py -b bkey.txt
The snag is that you need to get an API-key in order to use it; however, those are easy to get a hold of, as you can get up to 5000 searches per month for free: Azure Datamarket