diff --git a/wip/app/app2.php b/wip/app/app2.php
index fc667f9..f38f874 100644
--- a/wip/app/app2.php
+++ b/wip/app/app2.php
@@ -476,12 +476,19 @@ class app2 {
 
   #############################################################################
 
+  const EC_LOCKED = 252;
+  const EC_BAD_COMMAND = 253;
+  const EC_EXCEPTION = 254;
+  const EC_SIGNAL = 255;
+
+  #############################################################################
+
   static bool $dispach_signals = false;
 
   static function install_signal_handler(bool $allow=true): void {
     if (!$allow) return;
     $signalHandler = function(int $signo, $siginfo) {
-      throw new ExitError(255);
+      throw new ExitError(self::EC_SIGNAL);
     };
     pcntl_signal(SIGHUP, $signalHandler);
     pcntl_signal(SIGINT, $signalHandler);
diff --git a/wip/app/cli/Application.php b/wip/app/cli/Application.php
index 62ee7ad..4113412 100644
--- a/wip/app/cli/Application.php
+++ b/wip/app/cli/Application.php
@@ -105,7 +105,7 @@ abstract class Application {
       break;
     default:
       fwrite(STDERR, "$argv[2]: unexpected command\n");
-      $ec = 123;
+      $ec = app2::EC_BAD_COMMAND;
     }
     exit($ec);
   }
@@ -132,7 +132,7 @@ abstract class Application {
         $runfile = app2::get()->getRunfile();
 
         self::_manage_runfile($runfile);
-        if ($useRunlock && $runfile->warnIfLocked()) exit(1);
+        if ($useRunlock && $runfile->warnIfLocked()) exit(app2::EC_LOCKED);
 
         $runfile->wfStart();
         $stop = true;
@@ -149,7 +149,7 @@ abstract class Application {
       exit($e->getCode());
     } catch (Exception $e) {
       msg::error($e);
-      exit(1);
+      exit(app2::EC_EXCEPTION);
     }
   }