There is a module specifically built for this task - URI::Find. eg.

#!/usr/bin/perl -Tw

use URI;
use URI::Find;
use strict;

my $text = "... long string with lots of URLs ...";

find_uris($text, sub {
    my ($find_uri, $orig_uri) = @_;
    my $uri = URI->new( $orig_uri );
    $uri = $uri->canonical->as_string;
    return '<a href="' . $uri . '">' . $uri . '</a>';
});

print $text, "\n";
exit 0;
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Note that the CPAN documentation for URI::Find is out-of-date with the newest version (0.04) exporting only the one function, find_uris, which takes two arguments, the string to be searched and a function reference.

 

perl -e 's&&rob@cowsnet.com.au&&&split/[@.]/&&s&.com.&_&&&print'