use strict;
my $str = 'asdf
http://google.com/
asfd
http://yahoo.com/logo.jpg
http://www.apple.com/sdfsd.php?page_id=13&id=18210&status=active#1
http://youtube.com/logo.png';
my $regex = qr/(([A-Za-z]{3,9}:(?:\/\/)?(?:[-;:&=\+\$,\w]+@)?[A-Za-z0-9.-]+|(?:www.|[-;:&=\+\$,\w]+@)[A-Za-z0-9.-]+)((?:\/[\+~%\/.\w-_]*)?\??(?:[-\+=&;%@.\w_]*)#?(?:[\w]*))?)/p;
my $subst = '<a href="$1">$1</a>';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html