diff --git a/classes/backends/ComicPressBackendFilesystem.inc b/classes/backends/ComicPressBackendFilesystem.inc
new file mode 100644
index 0000000..457a887
--- /dev/null
+++ b/classes/backends/ComicPressBackendFilesystem.inc
@@ -0,0 +1,73 @@
+<?php
+
+require_once(dirname(__file__) . '/../ComicPressBackend.inc');
+
+class ComicPressBackendFilesystem extends ComicPressBackend {
+	var $search_string = '';
+
+	function process_search_string($post, $type) {
+		$this->_searches = array($this->search_string);
+
+		do {
+			$any_found = false;
+			for ($i = 0; $i < count($this->_searches); ++$i) {
+				$search = $this->_searches[$i];
+				if (preg_match('#%([a-z0-9\-]+)%#i', $search, $matches) > 0) {
+					$any_found = true;
+
+					$method = '_replace_' . strtolower(str_replace('-', '_', $matches[1]));
+					if (method_exists($this, $method)) {
+						$result = $this->{$method}($post, $type);
+						if ($result !== false) {
+							$this->_searches[$i] = str_replace($matches[0], $result, $search);
+						} else {
+							// array state change, start over
+							break;
+						}
+					} else {
+						$this->_searches[$i] = str_replace($matches[0], '', $search);
+					}
+				}
+			}
+		} while ($any_found);
+
+		return $this->_searches;
+	}
+
+	function _replace_wordpress($post, $type) {	return ABSPATH;	}
+	function _replace_type($post, $type) { return $type;	}
+	function _replace_y_m_d($post, $type) { return date('Y-m-d', strtotime($post->post_date));	}
+	function _replace_year($post, $type) { return date('Y', strtotime($post->post_date));	}
+	function _replace_categories($post, $type) {
+		if (count($post_categories = wp_get_post_categories($post->ID)) == 1) {
+			$current_parent = reset($post_categories);
+			$all_slugs = array();
+
+			do {
+				if ($keep_searching = ($current_parent != 0)) {
+					$category = get_category($current_parent);
+					if (!empty($category)) {
+						array_unshift($all_slugs, $category->slug);
+						$current_parent = $category->parent;
+					} else {
+						break;
+					}
+				}
+			} while ($keep_searching);
+
+			$new_searches = array();
+			$slug_count = count($all_slugs);
+			foreach ($this->_searches as $search) {
+				if ($slug_count == 0) {
+					$new_searches[] = preg_replace('#%categories%#i', '', $search);
+				} else {
+					for ($i = 0; $i < $slug_count; ++$i) {
+						$new_searches[] = preg_replace('#%categories%#i', implode('/', array_slice($all_slugs, 0, $slug_count - $i)), $search);
+					}
+				}
+			}
+			$this->_searches = $new_searches;
+		}
+		return false;
+	}
+}
\ No newline at end of file
diff --git a/test/backends/ComicPressBackendFilesystemTest.php b/test/backends/ComicPressBackendFilesystemTest.php
new file mode 100644
index 0000000..05696b9
--- /dev/null
+++ b/test/backends/ComicPressBackendFilesystemTest.php
@@ -0,0 +1,49 @@
+<?php
+
+require_once('PHPUnit/Framework.php');
+require_once('MockPress/mockpress.php');
+require_once('backends/ComicPressBackendFilesystem.inc');
+require_once('vfsStream/vfsStream.php');
+
+class ComicPressBackendFilesystemTest extends PHPUnit_Framework_TestCase {
+	function setUp() {
+		_reset_wp();
+		$this->fs = new ComicPressBackendFilesystem();
+	}
+
+	function providerTestProcessSearchString() {
+		return array(
+			array('/comic/*.jpg', array('/comic/*.jpg')),
+			array('%wordpress%/comic/*.jpg', array('/wordpress/comic/*.jpg')),
+			array('%wordpress%/%type%/*.jpg', array('/wordpress/comic/*.jpg')),
+			array('%wordpress%/comic/%y-m-d%*.jpg', array('/wordpress/comic/2009-01-01*.jpg')),
+			array('%wordpress%/comic/%year%/%y-m-d%*.jpg', array('/wordpress/comic/2009/2009-01-01*.jpg')),
+			array(
+			  '%wordpress%/comic/%categories%/%y-m-d%*.jpg',
+			  array(
+			    '/wordpress/comic/parent/child/2009-01-01*.jpg',
+			    '/wordpress/comic/parent/2009-01-01*.jpg',
+			  )
+			),
+		);
+	}
+
+	/**
+	 * @dataProvider providerTestProcessSearchString
+	 */
+	function testProcessSearchString($string, $expected_searches) {
+		$fs = $this->getMock('ComicPressBackendFilesystem', array('_replace_wordpress'));
+
+		$fs->expects($this->any())->method('_replace_wordpress')->will($this->returnValue('/wordpress'));
+
+		$post = (object)array('ID' => 1, 'post_date' => '2009-01-01');
+		add_category(1, (object)array('slug' => 'parent', 'parent' => 0));
+		add_category(2, (object)array('slug' => 'child', 'parent' => 1));
+
+		wp_set_post_categories(1, array(2));
+
+		$fs->search_string = $string;
+
+		$this->assertEquals($expected_searches, $fs->process_search_string($post, 'comic'));
+	}
+}
\ No newline at end of file