>>60
my $addr_spec = 'test@example.com';

# http://tohoho.wakusei.ne.jp/wwwperl2.htm#index
# http://tohoho.wakusei.ne.jp/wwwperl2.htm#substr
my $domain = substr $addr_spec, index($addr_spec, '@') + 1;

# http://www.kt.rim.or.jp/%7Ekbk/perl5.005/perlre.html
($domain) = $addr_spec =~ /([^@]+)\z/;