php实现ping

<?php
// created by joe lumbroso 
// see some other good php3 scripts 
// goto http://www.dtheatre.com/scripts
echo '<font color=\'red\'><blink><b>Pinging</b></blink></font><br>'; 
＄to_ping = 'dtheatre.com'; 
＄count = 3; 
＄psize = 65; 
echo ' Please be patient, this can take a few moments...\n<br><br>'; 
flush();
while (1) { 
?> 
<pre> 
<? 
exec('ping -c ＄count -s ＄psize ＄to_ping', ＄list); 
for (＄i=0;＄i < count(＄list);＄i ) { 
print ＄list[＄i].'\n'; 
} 
?> 
</pre> 
<? 
flush(); 
sleep(3); 
} 
?>