A php script which read a input txt file containing files to total the size of.

totalFileSize.php

<?php
// Read filenames from the input file, get their file sizes if possible and total it.
// Show the total in a human readable file size.

function human_filesize($bytes, $decimals = 2) {
    $size = array('B','kB','MB','GB','TB','PB','EB','ZB','YB');
    $factor = floor((strlen($bytes) - 1) / 3);
    return sprintf("%.{$decimals}f", $bytes / pow(1024, $factor)) . @$size[$factor];
}

$total = 0;
$count = 0;
$count_unable = 0;
$count_readfilesize = 0;

$handle = fopen("./filesToDelete.txt", "r");
if ($handle) {
    while (($line = fgets($handle)) !== false) {

        // Deal to any line endings?
        $line = rtrim($line);
        $count ++;

		$size = @filesize($line);
		if ($size !== false) {
            $total += $size;
            //echo "$line is ".human_filesize($size)."<br>";
            $count_readfilesize ++;
		} else {
            $count_unable ++;
        }
    }

    fclose($handle);
} else {
    die('Error opening input file.');
} 

echo "Total Files: $count<br>";
echo "Files Read: $count_readfilesize<br>";
echo "Unable to read count: $count_unable<br>";
echo "Total Size of files: ".human_filesize($total)."<br>";