#!/usr/bin/perl5 -wT  
use strict;  
                                                
$| = 1;  
if (!open (ADDCTX, "<ads.dta")) {die "Could not open file: $!";}  
flock(ADDCTX,1) or die "Could not lock file: $!";  
seek(ADDCTX,0,0);  
my @ads = <ADDCTX>;  
close(ADDCTX);  
my @TLAD = split(/\|/,$ads[rand @ads]);  
$TLAD[2]++;  
$ads[$TLAD[0]] = "$TLAD[0]|$TLAD[1]|$TLAD[2]\n";  
print "Content-type: text/html\n\n";  
print "Advertisement: $TLAD[1]";  
if (open (ADDCTZ, "+<ads.dta")) {  
flock(ADDCTZ,2) or die "Could not lock file: $!";  
truncate ADDCTZ,0;  
seek(ADDCTZ,0,0);  
print ADDCTZ @ads;  
close(ADDCTZ);  
}  
exit;