Creating a sheduled task from this code

[4thstar]

Hello.
I have modified the code from this module to create a file i can use for an rss feed of the events calendar, i dont know php so its been a bit of reading and trial and error, theres probably a much better way to do this, but for now it seems to work.

Problem is its done as a widget so it runs on every page load, which when the site gets bigger will get higher usage on the server.

Kan i ask if anyone out there can show me how to convert the code below so it runs as a sheduled task from a cron file?

Many thanks
Carl

PHP Code:

ob_start(); 
global $db,$vbulletin; 
$calendarid="1"; 
$per_page = "60"; 
//################################################ 
$d=date("d"); 
$m=date("m"); 
$y=date("y"); 
$sdate = mktime(0, 0, 0, date("$m"), date("$d"),  date("$y")); 
$edate = mktime(0, 0, 0, date("$m"), date("31"),  date("$y")); 
$and=" and dateline_from >= '".$sdate."'"; 

$getevents=$db->query_read("SELECT eventid, event, title, customfields, dateline_from from " . TABLE_PREFIX . "event WHERE calendarid='".$calendarid."' $and order by dateline_from ASC LIMIT $per_page"); 
$count=0; 
if(!$db->num_rows($getevents)) 
{ 
} 
else 
{ 
WHILE ($events=$db->fetch_array($getevents)) 
{ 
$eventdetails=$events['event'];
$eventdetails=substr($eventdetails, 0, 300);
$eventdetails .= "......";
$customfield=$events['customfields'];
$customfield = str_replace('a:0:{}', '', $customfield );
$customfield =strstr ($customfield, '"');
$customfield = str_replace('"', '', $customfield );
$customfield = str_replace(';}', '', $customfield );

$dtitle=$events['title']; 
$did=$events['eventid']; 
$date = vbdate('d-m-y',$events['dateline_from'], false,true,false,true); 
$dateext = vbdate('l jS F Y',$events['dateline_from'], false,true,false,true);
if ($count = 2){$class="alt2";}else {$class="alt1";} 
$year=date("Y"); 
$pagetitle = $f; 
$pagetitle .= " "; 
$pagetitle.=$year; 
$eventbits .=""; 

$dateext = htmlentities($dateext);
$eventdetails = htmlentities($eventdetails);


$eventbitsExt .="
<item>
<title>$dateext</title>
<description><![CDATA[$eventdetails]]></description>
<link><![CDATA[http://www.bidefordmarket.co.uk/calendar.php?do=getinfo&e=$did&c=$calendarid]]></link>
<guid><![CDATA[000000$did]]></guid>
<pubDate><![CDATA[$sdate]]></pubDate>
</item>
"; 
$count++; 
} 
} 


$bidefordmarketeventlist = "bidefordmarketeventlist.rss";
$fh = fopen($bidefordmarketeventlist, 'w') or die("can't open file");
fwrite($fh, "<?xml version='1.0' encoding='UTF-8' ?>
<rss version='2.0'>
<channel>
<title>Bideford Market Events</title>
<description>This is the RSS feed for Bideford Markets Latest Events</description>
<link>http://www.bidefordmarket.co.uk</link>
<lastBuildDate>$sdate</lastBuildDate>
<pubDate>$sdate</pubDate>
<ttl>1800</ttl>
");

//$eventbitsExt = str_replace("?", "?", $eventbitsExt);
//$eventbitsExt = str_replace("&", "&", $eventbitsExt);

$strfinda .= chr(150);
$eventbitsExt = str_replace($strfinda, " ", $eventbitsExt);


fwrite($fh, $eventbitsExt);
fwrite($fh, "</channel>
</rss>");
fclose($fh);


$db->free_result($getevents); 
unset($events); 
$output=ob_get_contents(); 
ob_end_clean();