Your code seemingly intentionally finds something other than the TLD in some situations.

It also mishandles a number of the valid urls listed below. Fix: 

$url = URI->new($url);

defined( my $host = $url->host() )
   or die("No host\n");

my $tld;
if ($host =~ /\./) {
   $tld = /\.([^.]+)$/;
   $tld =~ /[a-z]/i
      or die("No domain\n");
} else {
   $host =~ /[a-z]/i
      or die("No domain\n");
   $tld = 'localdomain';
}

[download]

Handles valid urls

Invalid urls aren't necessarily detected.

Update: Updated code to detects an invalid url it didn't detect before.

In reply to Re: Finding the Top Level Domain from a URL by ikegami
in thread Finding the Top Level Domain from a URL by downer

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