#!/usr/bin/perl -wT
# count.pl
use strict;
use Fcntl qw(:flock);
use Untaint;

my $counter = untaint(qr(.*\.dat$), $ARGV[0]);
my $silent = 0;
my $link = 1;
my $link_URL = "http://www.perl.org";
my $SEMAPHORE = $counter . ".lck";

open(S,">$SEMAPHORE") || die "Can't open Semaphore file ($SEMAPHORE): $!";

flock (S, LOCK_EX);

if (-e $counter) {
    open (FILE, $counter) || die "Can't read counter. $!";
    my $visits = <FILE>;
    close (FILE);
}

open (FILE, ">$counter") || die "Cant write to counter. $!";

print FILE ++$visits;

close (FILE);
close (S);

if (!$silent) {
    if ($link) {
        print qq(<A HREF="$link_URL">$visits</A>);
    else{
        print $visits;
    }
}