in reply to find the domain name from subdomian

$ perl -MURI -le"print URI->new( shift )->host " http://search.cpan.or
+g/
search.cpan.org

$ perl -MURI -le"print join q!.!, (split /\./, URI->new( shift )->host
+)[-2,-1] " http://search.cpan.org/
cpan.org

[download]
URI, Regexp::Common::dns

In Section Seekers of Perl Wisdom