Add some PHP-CLI scripts to be run as cronjobs

common/scripts/clean_old_thumbnails.php

@@ -0,0 +1,41 @@
+<?php
+
+/**
+ * This script deletes old thumbnails.
+ * 
+ * Thumbnails can take up a large amount of disk space and inodes if they are
+ * allowed to accumulate. Since most websites only need thumbnails for recent
+ * posts, it is okay to delete old thumbnails.
+ * 
+ * Do not run this script if you have a gallery-style module where visitors
+ * regularly view old posts. This will force thumbnails to be regenerated,
+ * increasing the server load and making your pages load slower.
+ * 
+ * This script only works on Unix-like operating systems where the 'find'
+ * command is available.
+ */
+require_once __DIR__ . '/common.php';
+
+// Delete thumbnails older than this number of days.
+$days = 90;
+
+// Initialize the exit status.
+$exit_status = 0;
+
+// Delete old thumbnails.
+passthru(sprintf('find %s -type f -mtime +%d -delete', escapeshellarg(RX_BASEDIR . 'files/thumbnails'), abs($days)), $result);
+if ($result == 0)
+{
+	echo "Successfully deleted all thumbnails older than $days days.\n";
+}
+else
+{
+	echo "Error while deleting thumbnails older than $days days.\n";
+	$exit_status = $result;
+}
+
+// Set the exit status if there were any errors.
+if ($exit_status != 0)
+{
+	exit($exit_status);
+}