I'm writing a web spider, I am currently trying to make it check itself against a file so it does not visit the same page twice. Here is what I have: (and perltidied too :))

#!/usr/bin/perl -w

use strict;
use diagnostics;
use LWP::RobotUA;
use URI::URL;

#use HTML::Parser ();
use HTML::SimpleLinkExtor;

my $a = 0;
my $links;
my $visited;
my $base;
my $u;
for ( $u = 1 ; $u < 1000000000 ; $u++ ) {
    open( FILE1, "</var/www/links/file$u.txt" ) || die;
    while (<FILE1>) {
        my $ua = LWP::RobotUA->new( 'theusefulbot', 'bot@theusefulnet.
+com' );

        #my $p = HTML::Parser->new();
        $ua->delay( 10 / 6000 );
        my $content = $ua->get($_)->content;

        #my $text = $p->parse($content)->parse;
        open( VISITED, ">>/var/www/links/visited.txt" ) || die;
        print VISITED "$_\n";
        close(VISITED);
        open( VISITED, "</var/www/links/visited.txt" ) || die;
        my $extor = HTML::SimpleLinkExtor->new($base);
        $extor->parse($content);
        my @links = $extor->a;
        $u++;
        open( FILE2, ">/var/www/links/file$u.txt" ) || die;

        foreach $links (@links) {
            my @visited = <VISITED>;
            foreach $visited (@visited) {
                if ( $visited eq $links ) {
                    print "Duplicate found";
                }
                else {
                    open( OUTPUT, ">/var/www/data/$a.txt" ) || die;
                    print OUTPUT "$_\n\n";
                    print OUTPUT "$content";
                    close(OUTPUT);
                    print FILE2 url("$links")->abs("$_");
                    print FILE2 "\n";
                }
            }
        }

        $a++;
        $u--;
    }
    close(FILE1);
    close(FILE2);
    close(VISITED);
    print "File #: $a\n";
}
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This still lets duplicate files exist, I know people have told me to use an array, but that would get rather large, so I'm just using a file, if you know exactly how to do it with an array, then that would be fine, so far I've gotten only "use shift".

Thanks