diff --git a/common/scripts/clean_empty_dirs.php b/common/scripts/clean_empty_dirs.php
new file mode 100644
index 000000000..faafdb135
--- /dev/null
+++ b/common/scripts/clean_empty_dirs.php
@@ -0,0 +1,58 @@
+<?php
+
+/**
+ * This script deletes empty directories under the 'files' directory.
+ * 
+ * It may be useful when your web host imposes a hard limit on the number of
+ * inodes, or when your backups take too long due to the large number of
+ * unused directories.
+ * 
+ * This script only works on Unix-like operating systems where the 'find'
+ * command is available.
+ */
+require_once __DIR__ . '/common.php';
+
+// Initialize the exit status.
+$exit_status = 0;
+
+// Delete empty directories in the attachment directory.
+passthru(sprintf('find %s -type d -empty -delete', escapeshellarg(RX_BASEDIR . 'files/attach')), $result);
+if ($result == 0)
+{
+	echo "Successfully deleted all empty directories under files/attach.\n";
+}
+else
+{
+	echo "Error while deleting empty directories under files/attach.\n";
+	$exit_status = $result;
+}
+
+// Delete empty directories in the member extra info directory.
+passthru(sprintf('find %s -type d -empty -delete', escapeshellarg(RX_BASEDIR . 'files/member_extra_info')), $result);
+if ($result == 0)
+{
+	echo "Successfully deleted all empty directories under files/member_extra_info.\n";
+}
+else
+{
+	echo "Error while deleting empty directories under files/member_extra_info.\n";
+	$exit_status = $result;
+}
+
+// Delete empty directories in the thumbnails directory.
+passthru(sprintf('find %s -type d -empty -delete', escapeshellarg(RX_BASEDIR . 'files/thumbnails')), $result);
+if ($result == 0)
+{
+	echo "Successfully deleted all empty directories under files/thumbnails.\n";
+}
+else
+{
+	echo "Error while deleting empty directories under files/thumbnails.\n";
+	$exit_status = $result;
+}
+
+// Set the exit status if there were any errors.
+if ($exit_status != 0)
+{
+	exit($exit_status);
+}
diff --git a/common/scripts/clean_garbage_files.php b/common/scripts/clean_garbage_files.php
new file mode 100644
index 000000000..a8cf05778
--- /dev/null
+++ b/common/scripts/clean_garbage_files.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * This script deletes files that were not properly uploaded.
+ * 
+ * Files can remain in an invalid status for two reasons: 1) a user abandons
+ * a document or comment after uploading files; or 2) a chunked upload is
+ * aborted without the server having any opportunity to clean it up.
+ * These files can obviously take up a lot of disk space. In order to prevent
+ * them from accumulating too much, you should run this script at least once
+ * every few days.
+ */
+require_once __DIR__ . '/common.php';
+
+// Delete garbage files older than this number of days.
+$days = 10;
+
+// Initialize the exit status.
+$exit_status = 0;
+
+// Set the exit status if there were any errors.
+if ($exit_status != 0)
+{
+	exit($exit_status);
+}
diff --git a/common/scripts/clean_old_notifications.php b/common/scripts/clean_old_notifications.php
new file mode 100644
index 000000000..46d9552e0
--- /dev/null
+++ b/common/scripts/clean_old_notifications.php
@@ -0,0 +1,37 @@
+<?php
+
+/**
+ * This script deletes old notifications.
+ * 
+ * Notifications must be dismissed as quickly as possible in order to prevent
+ * the ncenterlite_notify table from becoming too large. For best performance,
+ * you should run this script at least once every few days.
+ */
+require_once __DIR__ . '/common.php';
+
+// Delete notifications older than this number of days.
+$days = 30;
+
+// Initialize the exit status.
+$exit_status = 0;
+
+// Execute the query.
+$args = new stdClass;
+$args->old_date = date('YmdHis', time() - ($days * 86400));
+$output = executeQuery('ncenterlite.deleteNotifyAll', $args);
+if ($output->toBool())
+{
+	echo "Successfully deleted all notifications older than $days days.\n";
+}
+else
+{
+	echo "Error while deleting notifications older than $days days.\n";
+	echo $output->getMessage() . "\n";
+	$exit_status = abs($output->getError());
+}
+
+// Set the exit status if there were any errors.
+if ($exit_status != 0)
+{
+	exit($exit_status);
+}
diff --git a/common/scripts/clean_old_thumbnails.php b/common/scripts/clean_old_thumbnails.php
new file mode 100644
index 000000000..b36868973
--- /dev/null
+++ b/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($exit_status);
+}
diff --git a/common/scripts/common.php b/common/scripts/common.php
new file mode 100644
index 000000000..884ed3cb6
--- /dev/null
+++ b/common/scripts/common.php
@@ -0,0 +1,42 @@
+<?php
+
+/**
+ * This file must be included at the top of all shell scripts (cron jobs).
+ * 
+ * HERE BE DRAGONS.
+ * 
+ * Failure to perform the checks listed in this file at the top of a cron job,
+ * or any attempt to work around the limitations deliberately placed in this
+ * file, may result in errors or degradation of service.
+ * 
+ * Please be warned that errors may not show up immediately, especially if you
+ * screw up the permissions inside deeply nested directory trees. You may find
+ * it difficult and/or costly to undo the damages when errors begin to show up
+ * several months later.
+ */
+
+// Abort if not CLI.
+if (PHP_SAPI !== 'cli')
+{
+	echo "This script must be executed on the command line interface.\n";
+	exit(1);
+}
+
+// Load Rhymix.
+chdir(dirname(dirname(__DIR__)));
+require_once dirname(__DIR__) . '/autoload.php';
+
+// Abort if the UID does not match.
+$uid = Rhymix\Framework\Storage::getServerUID();
+if ($uid === 0)
+{
+	echo "This script must not be executed by the root user.\n";
+	exit(2);
+}
+$web_server_uid = fileowner(RX_BASEDIR . 'files/config/config.php');
+if ($uid !== $web_server_uid)
+{
+	$web_server_uid = posix_getpwuid($web_server_uid);
+	echo "This script must be executed by the same user as the usual web server process ({$web_server_uid['name']}).\n";
+	exit(3);
+}