Notes

Convert Excel timestamp to unix time: =(EXCEL-25569)*86400

Convert unix time to Excel timestamp: =(UNIX/86400)+25569

5 hour timezone offset is (-5*3600)=18000 seconds

gnuplot.php

<?
if(isset($_REQUEST["file"])) {
header('Content-type: image/png');
passthru("gnuplot ".escapeshellcmd($_REQUEST["file"]));
die();
}
$dir="/var/www/gnuplot/";
if (is_dir($dir)) {
	if ($dh = opendir($dir)) {
		while (($file = readdir($dh)) !== false) {
			$split=split("\.",$file);
#			print_r($split);
			if(filetype($dir . $file)=="file" && $split[1]=="gnuplot"){
				echo "<a href=\"gnuplot.php?file=".$split[0].".gnuplot\">".$split[0]."<BR>";
			}
		}
		closedir($dh);
		}
}
 
 
?>