diff --git a/admin/rehash.php b/admin/rehash.php
new file mode 100755
--- /dev/null
+++ b/admin/rehash.php
@@ -0,0 +1,153 @@
+#!/usr/bin/env php
+<?php
+/*
+ * Copyright 2010 Nathan Phillip Brink <ohnobinki@ohnopublishing.net>
+ *
+ * This file is a part of slate_permutate.
+ *
+ * slate_permutate is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * slate_permutate is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with slate_permutate.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * \file
+ *
+ * Runs through schools.d grabbing and caching data, such as the
+ * school listing used for the ``choose your school list''.
+ */
+
+require_once(dirname(__FILE__) . DIRECTORY_SEPARATOR . '..' . DIRECTORY_SEPARATOR . 'inc' . DIRECTORY_SEPARATOR . 'school.inc');
+return main($argc, $argv);
+
+function main($argc, $argv)
+{
+  $school_id_list = school_list();
+  if (!$school_id_list)
+    return 1;
+
+  $schools = array();
+  foreach ($school_id_list as $school_id)
+    {
+      $school = school_load($school_id);
+      if (!$school)
+	{
+	  fprintf(STDERR, "Error loading school with school_id=%s\n",
+		  $school_id);
+	  return 1;
+	}
+      $schools[] = $school;
+    }
+
+  if (school_cache($schools))
+    {
+      fprintf(STDERR, "Error writing out school cache\n");
+      return 1;
+    }
+
+  return 0;
+}
+
+/*
+ * functions which are only needed when recreating the cache.
+ */
+
+/**
+ * \brief
+ *   Returns the list of available school IDs or NULL on error.
+ */
+function school_list()
+{
+  $schoold_dir_name = dirname(__FILE__) . DIRECTORY_SEPARATOR . '..' . DIRECTORY_SEPARATOR . 'school.d';
+  $schoold_dir = opendir($schoold_dir_name);
+  if ($schoold_dir === FALSE)
+    {
+      fprintf(STDERR, "Unable to open school.d directory. Was using path: `%s'\n",
+	      $schoold_dir_Name);
+      return NULL;
+    }
+
+  $school_id_list = array();
+  while ($filename = readdir($schoold_dir))
+    {
+      if (!preg_match('/^([a-z0-9]+)\.inc$/', $filename, $matches))
+	continue;
+
+      $school_id_list[] = $matches[1];
+    }
+
+  closedir($schoold_dir);
+
+  return $school_id_list;
+}
+
+/**
+ * \brief
+ *   Write out the cache file which remembers the list of available
+ *   schools.
+ *
+ * \todo
+ *   If the list of displayed schools is to be sorted, this is the
+ *   place to do it.
+ *
+ * \param $schools
+ *   An array of school handles.
+ */
+function school_cache($schools)
+{
+  $list_cache = array();
+  $domain_cache = array();
+  foreach ($schools as $school)
+    {
+      $list_cache[$school['id']] = array(
+					 'name' => $school['name'],
+					 'url' => $school['url'],
+					 );
+      foreach ($school['domains'] as $school_domain)
+	{
+	  $domain_cache_ptr =& $domain_cache;
+
+	  $domain_parts = array_reverse(explode('.', $school_domain));
+	  while (count($domain_parts) > 1)
+	    {
+	      $domain_part = array_shift($domain_parts);
+	      if (!isset($domain_cache_ptr[$domain_part])
+		  || !is_array($domain_cache_ptr[$domain_part]))
+		$domain_cache_ptr[$domain_part] = array();
+	      $domain_cache_ptr =& $domain_cache_ptr[$domain_part];
+	    }
+	  /*
+	   * get the last part which is unambiguously identifies this
+	   * school combined with the previous parts
+	   */
+	  $domain_part = array_shift($domain_parts);
+	  $domain_cache_ptr[$domain_part] = $school['id'];
+	}
+    }
+
+  $cache = array('list' => $list_cache, 'domains' => $domain_cache);
+
+
+  $cache_file_name = dirname(__FILE__) . DIRECTORY_SEPARATOR . '..'
+    . DIRECTORY_SEPARATOR . 'cache' . DIRECTORY_SEPARATOR . 'schools';
+  $cache_file = fopen($cache_file_name, 'wb');
+  if ($cache_file === FALSE)
+    {
+      fprintf(STDERR, "Unable to open `%s' for writing\n",
+	      $cache_file_name);
+      return 1;
+    }
+  fwrite($cache_file, serialize($cache));
+  fclose($cache_file);
+
+  return 0;
+}