diff --git a/bin/differential b/bin/differential
new file mode 120000
--- /dev/null
+++ b/bin/differential
@@ -0,0 +1 @@
+../scripts/setup/manage_differential.php
\ No newline at end of file
diff --git a/scripts/setup/manage_differential.php b/scripts/setup/manage_differential.php
new file mode 100755
--- /dev/null
+++ b/scripts/setup/manage_differential.php
@@ -0,0 +1,21 @@
+#!/usr/bin/env php
+<?php
+
+$root = dirname(dirname(dirname(__FILE__)));
+require_once $root.'/scripts/__init_script__.php';
+
+$args = new PhutilArgumentParser($argv);
+$args->setTagline(pht('manage hunks'));
+$args->setSynopsis(<<<EOSYNOPSIS
+**differential** __command__ [__options__]
+    Manage Differential.
+
+EOSYNOPSIS
+  );
+$args->parseStandardArguments();
+
+$workflows = id(new PhutilClassMapQuery())
+  ->setAncestorClass('PhabricatorDifferentialManagementWorkflow')
+  ->execute();
+$workflows[] = new PhutilHelpArgumentWorkflow();
+$args->parseWorkflows($workflows);
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -386,6 +386,7 @@
     'DifferentialDiffContentRemovedHeraldField' => 'applications/differential/herald/DifferentialDiffContentRemovedHeraldField.php',
     'DifferentialDiffCreateController' => 'applications/differential/controller/DifferentialDiffCreateController.php',
     'DifferentialDiffEditor' => 'applications/differential/editor/DifferentialDiffEditor.php',
+    'DifferentialDiffExtractionEngine' => 'applications/differential/engine/DifferentialDiffExtractionEngine.php',
     'DifferentialDiffHeraldField' => 'applications/differential/herald/DifferentialDiffHeraldField.php',
     'DifferentialDiffHeraldFieldGroup' => 'applications/differential/herald/DifferentialDiffHeraldFieldGroup.php',
     'DifferentialDiffInlineCommentQuery' => 'applications/differential/query/DifferentialDiffInlineCommentQuery.php',
@@ -2143,6 +2144,8 @@
     'PhabricatorDifferenceEngine' => 'infrastructure/diff/PhabricatorDifferenceEngine.php',
     'PhabricatorDifferentialApplication' => 'applications/differential/application/PhabricatorDifferentialApplication.php',
     'PhabricatorDifferentialConfigOptions' => 'applications/differential/config/PhabricatorDifferentialConfigOptions.php',
+    'PhabricatorDifferentialExtractWorkflow' => 'applications/differential/management/PhabricatorDifferentialExtractWorkflow.php',
+    'PhabricatorDifferentialManagementWorkflow' => 'applications/differential/management/PhabricatorDifferentialManagementWorkflow.php',
     'PhabricatorDifferentialRevisionTestDataGenerator' => 'applications/differential/lipsum/PhabricatorDifferentialRevisionTestDataGenerator.php',
     'PhabricatorDiffusionApplication' => 'applications/diffusion/application/PhabricatorDiffusionApplication.php',
     'PhabricatorDiffusionConfigOptions' => 'applications/diffusion/config/PhabricatorDiffusionConfigOptions.php',
@@ -4334,6 +4337,7 @@
     'DifferentialDiffContentRemovedHeraldField' => 'DifferentialDiffHeraldField',
     'DifferentialDiffCreateController' => 'DifferentialController',
     'DifferentialDiffEditor' => 'PhabricatorApplicationTransactionEditor',
+    'DifferentialDiffExtractionEngine' => 'Phobject',
     'DifferentialDiffHeraldField' => 'HeraldField',
     'DifferentialDiffHeraldFieldGroup' => 'HeraldFieldGroup',
     'DifferentialDiffInlineCommentQuery' => 'PhabricatorDiffInlineCommentQuery',
@@ -6376,6 +6380,8 @@
     'PhabricatorDifferenceEngine' => 'Phobject',
     'PhabricatorDifferentialApplication' => 'PhabricatorApplication',
     'PhabricatorDifferentialConfigOptions' => 'PhabricatorApplicationConfigOptions',
+    'PhabricatorDifferentialExtractWorkflow' => 'PhabricatorDifferentialManagementWorkflow',
+    'PhabricatorDifferentialManagementWorkflow' => 'PhabricatorManagementWorkflow',
     'PhabricatorDifferentialRevisionTestDataGenerator' => 'PhabricatorTestDataGenerator',
     'PhabricatorDiffusionApplication' => 'PhabricatorApplication',
     'PhabricatorDiffusionConfigOptions' => 'PhabricatorApplicationConfigOptions',
diff --git a/src/applications/differential/engine/DifferentialDiffExtractionEngine.php b/src/applications/differential/engine/DifferentialDiffExtractionEngine.php
new file mode 100644
--- /dev/null
+++ b/src/applications/differential/engine/DifferentialDiffExtractionEngine.php
@@ -0,0 +1,90 @@
+<?php
+
+final class DifferentialDiffExtractionEngine extends Phobject {
+
+  private $viewer;
+  private $authorPHID;
+
+  public function setViewer(PhabricatorUser $viewer) {
+    $this->viewer = $viewer;
+    return $this;
+  }
+
+  public function getViewer() {
+    return $this->viewer;
+  }
+
+  public function setAuthorPHID($author_phid) {
+    $this->authorPHID = $author_phid;
+    return $this;
+  }
+
+  public function getAuthorPHID() {
+    return $this->authorPHID;
+  }
+
+  public function newDiffFromCommit(PhabricatorRepositoryCommit $commit) {
+    $viewer = $this->getViewer();
+
+    $repository = $commit->getRepository();
+    $identifier = $commit->getCommitIdentifier();
+    $monogram = $commit->getMonogram();
+
+    $drequest = DiffusionRequest::newFromDictionary(
+      array(
+        'user' => $viewer,
+        'repository' => $repository,
+      ));
+
+    $raw_diff = DiffusionQuery::callConduitWithDiffusionRequest(
+      $viewer,
+      $drequest,
+      'diffusion.rawdiffquery',
+      array(
+        'commit' => $identifier,
+      ));
+
+    // TODO: Support adds, deletes and moves under SVN.
+    if (strlen($raw_diff)) {
+      $changes = id(new ArcanistDiffParser())->parseDiff($raw_diff);
+    } else {
+      // This is an empty diff, maybe made with `git commit --allow-empty`.
+      // NOTE: These diffs have the same tree hash as their ancestors, so
+      // they may attach to revisions in an unexpected way. Just let this
+      // happen for now, although it might make sense to special case it
+      // eventually.
+      $changes = array();
+    }
+
+    $diff = DifferentialDiff::newFromRawChanges($viewer, $changes)
+      ->setRepositoryPHID($repository->getPHID())
+      ->setCreationMethod('commit')
+      ->setSourceControlSystem($repository->getVersionControlSystem())
+      ->setLintStatus(DifferentialLintStatus::LINT_AUTO_SKIP)
+      ->setUnitStatus(DifferentialUnitStatus::UNIT_AUTO_SKIP)
+      ->setDateCreated($commit->getEpoch())
+      ->setDescription($monogram);
+
+    $author_phid = $this->getAuthorPHID();
+    if ($author_phid !== null) {
+      $diff->setAuthorPHID($author_phid);
+    }
+
+    $parents = DiffusionQuery::callConduitWithDiffusionRequest(
+      $viewer,
+      $drequest,
+      'diffusion.commitparentsquery',
+      array(
+        'commit' => $identifier,
+      ));
+
+    if ($parents) {
+      $diff->setSourceControlBaseRevision(head($parents));
+    }
+
+    // TODO: Attach binary files.
+
+    return $diff->save();
+  }
+
+}
diff --git a/src/applications/differential/management/PhabricatorDifferentialExtractWorkflow.php b/src/applications/differential/management/PhabricatorDifferentialExtractWorkflow.php
new file mode 100644
--- /dev/null
+++ b/src/applications/differential/management/PhabricatorDifferentialExtractWorkflow.php
@@ -0,0 +1,63 @@
+<?php
+
+final class PhabricatorDifferentialExtractWorkflow
+  extends PhabricatorDifferentialManagementWorkflow {
+
+  protected function didConstruct() {
+    $this
+      ->setName('extract')
+      ->setExamples('**extract** __commit__')
+      ->setSynopsis(pht('Extract a diff from a commit.'))
+      ->setArguments(
+        array(
+          array(
+            'name' => 'extract',
+            'wildcard' => true,
+            'help' => pht('Commit to extract.'),
+          ),
+        ));
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    $viewer = $this->getViewer();
+
+    $extract = $args->getArg('extract');
+
+    if (!$extract) {
+      throw new PhutilArgumentUsageException(
+        pht('Specify a commit to extract the diff from.'));
+    }
+
+    if (count($extract) > 1) {
+      throw new PhutilArgumentUsageException(
+        pht('Specify exactly one commit to extract.'));
+    }
+
+    $extract = head($extract);
+
+    $commit = id(new DiffusionCommitQuery())
+      ->setViewer($viewer)
+      ->withIdentifiers(array($extract))
+      ->executeOne();
+
+    if (!$commit) {
+      throw new PhutilArgumentUsageException(
+        pht(
+          'Commit "%s" is not valid.',
+          $extract));
+    }
+
+    $diff = id(new DifferentialDiffExtractionEngine())
+      ->setViewer($viewer)
+      ->newDiffFromCommit($commit);
+
+    $uri = PhabricatorEnv::getProductionURI($diff->getURI());
+
+    echo tsprintf(
+      "%s\n\n    %s\n",
+      pht('Extracted diff from "%s":', $extract),
+      $uri);
+  }
+
+
+}
diff --git a/src/applications/differential/management/PhabricatorDifferentialManagementWorkflow.php b/src/applications/differential/management/PhabricatorDifferentialManagementWorkflow.php
new file mode 100644
--- /dev/null
+++ b/src/applications/differential/management/PhabricatorDifferentialManagementWorkflow.php
@@ -0,0 +1,4 @@
+<?php
+
+abstract class PhabricatorDifferentialManagementWorkflow
+  extends PhabricatorManagementWorkflow {}
diff --git a/src/applications/differential/storage/DifferentialDiff.php b/src/applications/differential/storage/DifferentialDiff.php
--- a/src/applications/differential/storage/DifferentialDiff.php
+++ b/src/applications/differential/storage/DifferentialDiff.php
@@ -385,6 +385,12 @@
     return $map;
   }
 
+  public function getURI() {
+    $id = $this->getID();
+    return "/differential/diff/{$id}/";
+  }
+
+
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
 
diff --git a/src/applications/repository/worker/commitmessageparser/PhabricatorRepositoryCommitMessageParserWorker.php b/src/applications/repository/worker/commitmessageparser/PhabricatorRepositoryCommitMessageParserWorker.php
--- a/src/applications/repository/worker/commitmessageparser/PhabricatorRepositoryCommitMessageParserWorker.php
+++ b/src/applications/repository/worker/commitmessageparser/PhabricatorRepositoryCommitMessageParserWorker.php
@@ -216,7 +216,10 @@
               $low_level_query->getRevisionMatchData());
           }
 
-          $diff = $this->generateFinalDiff($revision, $acting_as_phid);
+          $diff = id(new DifferentialDiffExtractionEngine())
+            ->setViewer($actor)
+            ->setAuthorPHID($acting_as_phid)
+            ->newDiffFromCommit($commit);
 
           $vs_diff = $this->loadChangedByCommit($revision, $diff);
           $changed_uri = null;
@@ -277,65 +280,6 @@
       PhabricatorRepositoryCommit::IMPORTED_MESSAGE);
   }
 
-  private function generateFinalDiff(
-    DifferentialRevision $revision,
-    $actor_phid) {
-
-    $viewer = PhabricatorUser::getOmnipotentUser();
-
-    $drequest = DiffusionRequest::newFromDictionary(array(
-      'user' => $viewer,
-      'repository' => $this->repository,
-    ));
-
-    $raw_diff = DiffusionQuery::callConduitWithDiffusionRequest(
-      $viewer,
-      $drequest,
-      'diffusion.rawdiffquery',
-      array(
-        'commit' => $this->commit->getCommitIdentifier(),
-      ));
-
-    // TODO: Support adds, deletes and moves under SVN.
-    if (strlen($raw_diff)) {
-      $changes = id(new ArcanistDiffParser())->parseDiff($raw_diff);
-    } else {
-      // This is an empty diff, maybe made with `git commit --allow-empty`.
-      // NOTE: These diffs have the same tree hash as their ancestors, so
-      // they may attach to revisions in an unexpected way. Just let this
-      // happen for now, although it might make sense to special case it
-      // eventually.
-      $changes = array();
-    }
-
-    $diff = DifferentialDiff::newFromRawChanges($viewer, $changes)
-      ->setRepositoryPHID($this->repository->getPHID())
-      ->setAuthorPHID($actor_phid)
-      ->setCreationMethod('commit')
-      ->setSourceControlSystem($this->repository->getVersionControlSystem())
-      ->setLintStatus(DifferentialLintStatus::LINT_AUTO_SKIP)
-      ->setUnitStatus(DifferentialUnitStatus::UNIT_AUTO_SKIP)
-      ->setDateCreated($this->commit->getEpoch())
-      ->setDescription(
-        pht(
-          'Commit %s',
-          $this->commit->getMonogram()));
-
-    $parents = DiffusionQuery::callConduitWithDiffusionRequest(
-      $viewer,
-      $drequest,
-      'diffusion.commitparentsquery',
-      array(
-        'commit' => $this->commit->getCommitIdentifier(),
-      ));
-    if ($parents) {
-      $diff->setSourceControlBaseRevision(head($parents));
-    }
-
-    // TODO: Attach binary files.
-
-    return $diff->save();
-  }
 
   private function loadChangedByCommit(
     DifferentialRevision $revision,