diff --git a/scripts/repository/parse_one_commit.php b/scripts/repository/parse_one_commit.php
index 750d4507c1..855899b8bd 100755
--- a/scripts/repository/parse_one_commit.php
+++ b/scripts/repository/parse_one_commit.php
@@ -17,69 +17,7 @@
  * limitations under the License.
  */
 
-$root = dirname(dirname(dirname(__FILE__)));
-require_once $root.'/scripts/__init_script__.php';
-require_once $root.'/scripts/__init_env__.php';
-
-if (empty($argv[1])) {
-  echo "usage: parse_one_commit.php <commit_name> [--herald]\n";
-  die(1);
-}
-
-$commit = isset($argv[1]) ? $argv[1] : null;
-if (!$commit) {
-  throw new Exception("Provide a commit to parse!");
-}
-$matches = null;
-if (!preg_match('/r([A-Z]+)([a-z0-9]+)/', $commit, $matches)) {
-  throw new Exception("Can't parse commit identifier!");
-}
-$repo = id(new PhabricatorRepository())->loadOneWhere(
-  'callsign = %s',
-  $matches[1]);
-if (!$repo) {
-  throw new Exception("Unknown repository!");
-}
-$commit = id(new PhabricatorRepositoryCommit())->loadOneWhere(
-  'repositoryID = %d AND commitIdentifier = %s',
-  $repo->getID(),
-  $matches[2]);
-if (!$commit) {
-  throw new Exception('Unknown commit.');
-}
-
-$workers = array();
-
-$spec = array(
-  'commitID'  => $commit->getID(),
-  'only'      => true,
-);
-
-switch ($repo->getVersionControlSystem()) {
-  case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
-    $workers[] = new PhabricatorRepositoryGitCommitMessageParserWorker(
-      $spec);
-    $workers[] = new PhabricatorRepositoryGitCommitChangeParserWorker(
-      $spec);
-    break;
-  case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
-    $workers[] = new PhabricatorRepositorySvnCommitMessageParserWorker(
-      $spec);
-    $workers[] = new PhabricatorRepositorySvnCommitChangeParserWorker(
-      $spec);
-    break;
-  default:
-    throw new Exception("Unknown repository type!");
-}
-
-if (isset($argv[2]) && $argv[2] == '--herald') {
-  $workers[] = new PhabricatorRepositoryCommitHeraldWorker($spec);
-}
-
-foreach ($workers as $worker) {
-  echo "Running ".get_class($worker)."...\n";
-  $worker->doWork();
-}
-
-echo "Done.\n";
-
+echo "This script is obsolete. Instead, use:\n\n".
+     "  $ reparse.php <commit_name> --message --change\n\n".
+     "See that script for more options.\n";
+exit(1);
diff --git a/scripts/repository/reparse.php b/scripts/repository/reparse.php
new file mode 100755
index 0000000000..c9d435fff5
--- /dev/null
+++ b/scripts/repository/reparse.php
@@ -0,0 +1,236 @@
+#!/usr/bin/env php
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+$root = dirname(dirname(dirname(__FILE__)));
+require_once $root.'/scripts/__init_script__.php';
+require_once $root.'/scripts/__init_env__.php';
+
+phutil_require_module('phutil', 'console');
+
+$is_all = false;
+$reparse_message = false;
+$reparse_change = false;
+$reparse_herald = false;
+$reparse_what = false;
+
+$args = array_slice($argv, 1);
+foreach ($args as $arg) {
+  if (!strncmp($arg, '--', 2)) {
+    $flag = substr($arg, 2);
+    switch ($flag) {
+      case 'all':
+        $is_all = true;
+        break;
+      case 'message':
+      case 'messages':
+        $reparse_message = true;
+        break;
+      case 'change':
+      case 'changes':
+        $reparse_change = true;
+        break;
+      case 'herald':
+        $reparse_herald = true;
+        break;
+      case 'trace':
+        PhutilServiceProfiler::installEchoListener();
+        break;
+      case 'help':
+        help();
+        break;
+      default:
+        usage("Unknown flag '{$arg}'.");
+    }
+  } else {
+    if ($reparse_what) {
+      usage("Specify exactly one thing to reparse.");
+    }
+    $reparse_what = $arg;
+  }
+}
+
+if (!$reparse_what) {
+  usage("Specify a commit or repository to reparse.");
+}
+if (!$reparse_message && !$reparse_change && !$reparse_herald) {
+  usage("Specify what information to reparse with --message, --change, and/or ".
+        "--herald.");
+}
+
+$commits = array();
+if ($is_all) {
+  $repository = id(new PhabricatorRepository())->loadOneWhere(
+    'callsign = %s OR phid = %s',
+    $reparse_what,
+    $reparse_what);
+  if (!$repository) {
+    throw new Exception("Unknown repository '{$reparse_what}'!");
+  }
+  $commits = id(new PhabricatorRepositoryCommit())->loadAllWhere(
+    'repositoryID = %d',
+    $repository->getID());
+  if (!$commits) {
+    throw new Exception("No commits have been discovered in that repository!");
+  }
+  $callsign = $repository->getCallsign();
+} else {
+  $matches = null;
+  if (!preg_match('/r([A-Z]+)([a-z0-9]+)/', $reparse_what, $matches)) {
+    throw new Exception("Can't parse commit identifier!");
+  }
+  $callsign = $matches[1];
+  $commit_identifier = $matches[2];
+  $repository = id(new PhabricatorRepository())->loadOneWhere(
+    'callsign = %s',
+    $callsign);
+  if (!$repository) {
+    throw new Exception("No repository with callsign '{$callsign}'!");
+  }
+  $commit = id(new PhabricatorRepositoryCommit())->loadOneWhere(
+    'repositoryID = %d AND commitIdentifier = %s',
+    $repository->getID(),
+    $commit_identifier);
+  if (!$commit) {
+    throw new Exception(
+      "No matching commit '{$commit_identifier}' in repository '{$callsign}'. ".
+      "(For git and mercurial repositories, you must specify the entire ".
+      "commit hash.)");
+  }
+  $commits = array($commit);
+}
+
+if ($is_all) {
+  echo phutil_console_format(
+    '**NOTE**: This script will queue tasks to reparse the data. Once the '.
+    'tasks have been queued, you need to run Taskmaster daemons to execute '.
+    'them.');
+  echo "\n\n";
+  echo "QUEUEING TASKS (".number_format(count($commits))." Commits):\n";
+}
+
+$tasks = array();
+foreach ($commits as $commit) {
+  $classes = array();
+  switch ($repository->getVersionControlSystem()) {
+    case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
+      if ($reparse_message) {
+        $classes[] = 'PhabricatorRepositoryGitCommitMessageParserWorker';
+      }
+      if ($reparse_change) {
+        $classes[] = 'PhabricatorRepositoryGitCommitChangeParserWorker';
+      }
+      break;
+    case PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL:
+      if ($reparse_message) {
+        $classes[] = 'PhabricatorRepositoryMercurialCommitMessageParserWorker';
+      }
+      if ($reparse_change) {
+        $classes[] = 'PhabricatorRepositoryMercurialCommitChangeParserWorker';
+      }
+      break;
+    case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
+      if ($reparse_message) {
+        $classes[] = 'PhabricatorRepositorySvnCommitMessageParserWorker';
+      }
+      if ($reparse_change) {
+        $classes[] = 'PhabricatorRepositorySvnCommitChangeParserWorker';
+      }
+      break;
+  }
+
+  if ($reparse_herald) {
+    $classes[] = 'PhabricatorRepositoryCommitHeraldWorker';
+  }
+
+  $spec = array(
+    'commitID'  => $commit->getID(),
+    'only'      => true,
+  );
+
+  if ($is_all) {
+    foreach ($classes as $class) {
+      $task = new PhabricatorWorkerTask();
+      $task->setTaskClass($class);
+      $task->setData($spec);
+      $task->save();
+
+      $commit_name = 'r'.$callsign.$commit->getCommitIdentifier();
+      echo "  Queued '{$class}' for commit '{$commit_name}'.\n";
+    }
+  } else {
+    foreach ($classes as $class) {
+      $worker = newv($class, array($spec));
+      echo "Running '{$class}'...\n";
+      $worker->doWork();
+    }
+  }
+}
+
+echo "\nDone.\n";
+
+function usage($message) {
+  echo "Usage Error: {$message}";
+  echo "\n\n";
+  echo "Run 'reparse.php --help' for detailed help.\n";
+  exit(1);
+}
+
+function help() {
+  $help = <<<EOHELP
+**SUMMARY**
+
+    **reparse.php** __what__ __which_parts__ [--trace]
+
+    Rerun the Diffusion parser on specific commits and repositories. Mostly
+    useful for debugging changes to Diffusion.
+
+    __what__: what to reparse
+
+        __commit__
+            Reparse one commit. This mode will reparse the commit in-process.
+
+        --all __repository_callsign__
+        --all __repository_phid__
+            Reparse all commits in the specified repository. These modes queue
+            parsers into the task queue, you must run taskmasters to actually
+            do the parses them.
+
+    __which_parts__: which parts of the thing to reparse
+
+        __--message__
+            Reparse commit messages.
+
+        __--change__
+            Reparse changes.
+
+        __--herald__
+            Reevaluate Herald rules (may send huge amounts of email!)
+
+    __--trace__: run with debug tracing
+    __--help__: show this help
+
+**EXAMPLES**
+
+  reparse.php rX123 --change       # Reparse change for "rX123".
+  reparse.php --all E --message    # Reparse all messages in "E" repository.
+
+EOHELP;
+  echo phutil_console_format($help);
+  exit(1);
+}
diff --git a/scripts/repository/reparse_all_commit_messages.php b/scripts/repository/reparse_all_commit_messages.php
index b9fac56381..0b02192496 100755
--- a/scripts/repository/reparse_all_commit_messages.php
+++ b/scripts/repository/reparse_all_commit_messages.php
@@ -17,79 +17,8 @@
  * limitations under the License.
  */
 
-$root = dirname(dirname(dirname(__FILE__)));
-require_once $root.'/scripts/__init_script__.php';
-require_once $root.'/scripts/__init_env__.php';
+echo "This script is obsolete. Instead, use:\n\n".
+     "  $ reparse.php --all <repository_name> --message\n\n".
+     "See that script for more options.\n";
+exit(1);
 
-phutil_require_module('phutil', 'console');
-
-if (empty($argv[1])) {
-  echo "usage: reparse_all_commit_messages.php all\n".
-       "       reparse_all_commit_messages.php <repository_callsign>\n";
-  exit(1);
-}
-
-
-echo phutil_console_format(
-  'This script will queue tasks to reparse every commit message known to '.
-  'Diffusion. Once the tasks have been inserted, you need to start '.
-  'Taskmaster daemons to execute them.');
-
-$ok = phutil_console_confirm('Do you want to continue?');
-if (!$ok) {
-  die(1);
-}
-
-if ($argv[1] == 'all') {
-  echo "Loading all repositories...\n";
-  $repositories = id(new PhabricatorRepository())->loadAll();
-  echo "Loading all commits...\n";
-  $commits = id(new PhabricatorRepositoryCommit())->loadAll();
-} else {
-  $callsign = $argv[1];
-  echo "Loading '{$callsign}' repository...\n";
-  $repository = id(new PhabricatorRepository())->loadOneWhere(
-    'callsign = %s',
-    $argv[1]);
-  if (!$repository) {
-    throw new Exception("No such repository exists!");
-  }
-  $repositories = array(
-    $repository->getID() => $repository,
-  );
-  echo "Loading commits in '{$callsign}' repository...\n";
-  $commits = id(new PhabricatorRepositoryCommit())->loadAllWhere(
-    'repositoryID = %d',
-    $repository->getID());
-}
-
-echo "Inserting tasks for ".count($commits)." commits";
-foreach ($commits as $commit) {
-  echo ".";
-  $id = $commit->getID();
-  $repo = idx($repositories, $commit->getRepositoryID());
-  if (!$repo) {
-    echo "\nWarning: Commit #{$id} has an invalid repository ID.\n";
-  }
-
-  switch ($repo->getVersionControlSystem()) {
-    case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
-      $task_class = 'PhabricatorRepositoryGitCommitMessageParserWorker';
-      break;
-    case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
-      $task_class = 'PhabricatorRepositorySvnCommitMessageParserWorker';
-      break;
-    default:
-      throw new Exception("Unknown repository type!");
-  }
-
-  $task = new PhabricatorWorkerTask();
-  $task->setTaskClass($task_class);
-  $task->setData(
-    array(
-      'commitID'  => $commit->getID(),
-      'only'      => true,
-    ));
-  $task->save();
-}
-echo "\nDone.\n";
diff --git a/src/applications/daemon/controller/workertaskdetail/PhabricatorWorkerTaskDetailController.php b/src/applications/daemon/controller/workertaskdetail/PhabricatorWorkerTaskDetailController.php
index d4acf74840..3eb9d24d1e 100644
--- a/src/applications/daemon/controller/workertaskdetail/PhabricatorWorkerTaskDetailController.php
+++ b/src/applications/daemon/controller/workertaskdetail/PhabricatorWorkerTaskDetailController.php
@@ -62,10 +62,12 @@ class PhabricatorWorkerTaskDetailController
                 "<strong>NOTE:</strong> ".
                 "You can manually retry this task by running this script:".
                 "<pre>".
-                  "phabricator/\$ ./scripts/repository/parse_one_commit.php ".
+                  "phabricator/\$ ./scripts/repository/reparse.php ".
                   "r".
                   phutil_escape_html($repository->getCallsign()).
                   phutil_escape_html($commit->getCommitIdentifier()).
+                  " ".
+                  "--change".
                 "</pre>";
             }
           }