#!/usr/bin/perl

open(IN,"counts");
flock(IN,2);			# lock the file
seek(IN,0,0);			# rewind it to the beginning

$count = <IN>;			# read only the first line.
close(IN);

$count = $count + 1;

open(OUT,">counts");
flock(OUT,2);			# lock the file
seek(OUT,0,0);			# rewind it to the beginning
print OUT "$count\n";
close(OUT);

print "Content-type:text/html\n\n";
print "You are visitor number $count.<p>\n";