diff --git a/update.php b/update.php
new file mode 100644
index 0000000..e3dde2a
--- /dev/null
+++ b/update.php
@@ -0,0 +1,201 @@
+<?php
+/**
+ * Simple OAI-PMH 2.0 Data Provider
+ * Copyright (C) 2017 Sebastian Meyer <sebastian.meyer@opencultureconsulting.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+// Make this script only executable via commandline interface!
+if (php_sapi_name() !== 'cli') exit;
+
+require_once('oai2config.php');
+
+/**
+ * Format output string
+ *
+ * @param string $text
+ * @param string $format 'green' or 'red'
+ *
+ * @return string
+ */
+function format($text, $format = '') {
+
+    switch ($format) {
+
+        case 'green':
+            $text = "\033[0;92m$text\033[0m";
+            break;
+
+        case 'red':
+            $text = "\033[1;91m$text\033[0m";
+            break;
+
+        default:
+            break;
+
+    }
+
+    return $text;
+
+}
+
+// Check mandatory cli arguments
+if (empty($argc) || $argc != 3) {
+
+    echo "Usage:\n";
+    echo "  php update.php [sourceDir] [metadataPrefix]\n";
+    echo "\n";
+    echo "Example:\n";
+    echo "  php update.php /tmp/import oai_dc\n";
+    echo "\n";
+
+    exit;
+
+}
+
+list(, $sourceDir, $metadataPrefix) = $argv;
+
+// Check metadataPrefix
+if (empty($config['metadataFormats'][$metadataPrefix])) {
+
+    echo "Error: metadataPrefix $metadataPrefix not defined in oai2config.php\n";
+
+    exit;
+
+}
+
+// Check sourceDir permissions
+if (!is_dir($sourceDir) || !is_readable($sourceDir)) {
+
+    echo "Error: $sourceDir not readable\n";
+
+    exit;
+
+}
+
+$sourceDir = rtrim($sourceDir, '/').'/';
+
+// Check dataDir permissions
+$dataDir = rtrim($config['dataDirectory'], '/').'/'.$metadataPrefix.'/';
+
+if (!is_dir($dataDir) || !is_writable($dataDir)) {
+
+    echo "Error: $dataDir not writable\n";
+
+    exit;
+
+}
+
+// Alright, let's start!
+echo "Updating $dataDir from $sourceDir\n";
+
+$todo = array ();
+
+$error = false;
+
+$oldFiles = glob($dataDir.'*.xml');
+
+foreach ($oldFiles as $oldFile) {
+
+    $todo[pathinfo($oldFile, PATHINFO_FILENAME)] = 'delete';
+
+}
+
+$newFiles = glob($sourceDir.'*.xml');
+
+foreach ($newFiles as $newFile) {
+
+    $todo[pathinfo($newFile, PATHINFO_FILENAME)] = 'update';
+
+}
+
+foreach ($todo as $identifier => $task) {
+
+    echo "  Checking record $identifier ... ";
+
+    if ($task === 'update') {
+
+        if (!file_exists($dataDir.$identifier.'.xml')) {
+
+            // Add file
+            if (copy($sourceDir.$identifier.'.xml', $dataDir.$identifier.'.xml')) {
+
+                echo format('added', 'green')."\n";
+
+            } else {
+
+                echo format('addition failed', 'red')."\n";
+
+                $error = true;
+
+            }
+
+        } elseif (md5_file($sourceDir.$identifier.'.xml') !== md5_file($dataDir.$identifier.'.xml')) {
+
+            // Replace file
+            if (copy($sourceDir.$identifier.'.xml', $dataDir.$identifier.'.xml')) {
+
+                echo format('updated', 'green')."\n";
+
+            } else {
+
+                echo format('update failed', 'red')."\n";
+
+                $error = true;
+
+            }
+
+        } else {
+
+            echo "unchanged\n";
+
+        }
+
+    } elseif ($task === 'delete') {
+
+        if (filesize($dataDir.$identifier.'.xml') !== 0) {
+
+            // Truncate file
+            if (fclose(fopen($dataDir.$identifier.'.xml', 'w'))) {
+
+                echo format('deleted', 'green')."\n";
+
+            } else {
+
+                echo format('deletion failed', 'red')."\n";
+
+                $error = true;
+
+            }
+
+        } else {
+
+            echo "unchanged\n";
+
+        }
+
+    }
+
+}
+
+if ($error) {
+
+    echo "Update completed, but errors occurred. Please check the logs!\n";
+
+} else {
+
+    echo "Update successfully completed!\n";
+
+}