[wlug] Assistance on nzip.meta.net.nz

Hi all, I am in need of a single standalone perl script that will open a file with a list of all of the subnets (ordered and each subnet is on a newline) and then remove any overlapping, unneeded subnets and print the output to stdout. I am unable to figure this out for myself and have been trying for a while. My only results are of unoptimised code and isn't useful at all. Thanks in advance, Drew