http://riverserver/dir1/dir2/index.html
http://riverserver/dir1/dir2/index.html
http://perlmonks.org/index.pl
http://webserver.company.serv/Adir/Bdir/thePage.cfm
http://riverserver/dir1/dir2/index.html
http://webserver.company.serv/Adir/Bdir/thePage.cfm
##</code><code>##

riverserver = 3
perlmonks.org = 1
webserver.company.serv = 2
##</code><code>##

use strict;
my $link1 = 'http://perlmonks.org/index.pl';
my $link2 = 'http://riverserver/dir1/dir2/index.html';
#more links etc...
$link1 =~ s/http\:\/\///;
$link2 =~ s/http\:\/\///;

my @link1 = split /\//, $link1;
my @link2 = split /\//, $link2;

print "$link1[0]\n";
print "$link2[0]\n";