diff --git a/lib/AbstractException.php b/lib/AbstractException.php
index d2cb0d5..47caf39 100644
--- a/lib/AbstractException.php
+++ b/lib/AbstractException.php
@@ -102,6 +102,10 @@ abstract class AbstractException extends \Exception {
         "ImportExport/Exception.invalidFolderCopy"    => 10614,
         "ImportExport/Exception.invalidTagName"       => 10615,
         "Rule/Exception.invalidPattern"               => 10701,
+        "CLI/Exception.pidNotFile"                    => 10801,
+        "CLI/Exception.pidDirNotFound"                => 10802,
+        "CLI/Exception.pidUnwritable"                 => 10803,
+        "CLI/Exception.pidUncreatable"                => 10804,
     ];
 
     protected $symbol;
diff --git a/lib/CLI.php b/lib/CLI.php
index c52c508..433502e 100644
--- a/lib/CLI.php
+++ b/lib/CLI.php
@@ -331,24 +331,24 @@ USAGE_TEXT;
     }
 
     /** Resolves the PID file path and ensures the file or parent directory is writable */
-    protected function resolvePID(string $pidfile): string {
+    public function resolvePID(string $pidfile): string {
         $dir = dirname($pidfile);
         $file = basename($pidfile);
         if (!strlen($file)) {
-            throw new \Exception("Specified PID file location must be a regular file");
+            throw new CLI\Exception("pidNotFile", ['pidfile' => $dir]);
         } elseif ($base = @realpath($dir)) {
             $out = "$base/$file";
             if (file_exists($out)) {
                 if (!is_writable($out)) {
                     throw new \Exception("PID file is not writable");
                 } elseif (!is_file($out)) {
-                    throw new \Exception("Specified PID file location must be a regular file");
+                    throw new CLI\Exception("pidNotFile", ['pidfile' => $out]);
                 }
             } elseif (!is_writable($base)) {
                 throw new \Exception("Cannot create PID file");
             }
         } else {
-            throw new \Exception("Parent directory of PID file does not exist");
+            throw new \Exception("pidDirNotFound", ['piddir' => $dir]);
         }
         return $out;
     }
diff --git a/lib/CLI/Exception.php b/lib/CLI/Exception.php
new file mode 100644
index 0000000..7fe7c79
--- /dev/null
+++ b/lib/CLI/Exception.php
@@ -0,0 +1,10 @@
+<?php
+/** @license MIT
+ * Copyright 2017 J. King, Dustin Wilson et al.
+ * See LICENSE and AUTHORS files for details */
+
+declare(strict_types=1);
+namespace JKingWeb\Arsse\CLI;
+
+class Exception extends \JKingWeb\Arsse\AbstractException {
+}
diff --git a/locale/en.php b/locale/en.php
index 470d09e..66b9700 100644
--- a/locale/en.php
+++ b/locale/en.php
@@ -207,5 +207,9 @@ return [
     'Exception.JKingWeb/Arsse/ImportExport/Exception.invalidFolderName'    => 'Input data contains an invalid folder name',
     'Exception.JKingWeb/Arsse/ImportExport/Exception.invalidFolderCopy'    => 'Input data contains multiple folders of the same name under the same parent',
     'Exception.JKingWeb/Arsse/ImportExport/Exception.invalidTagName'       => 'Input data contains an invalid tag name',
-    'Exception.JKingWeb/Arsse/Rule/Exception.invalidPattern'               => 'Specified rule pattern is invalid'
+    'Exception.JKingWeb/Arsse/Rule/Exception.invalidPattern'               => 'Specified rule pattern is invalid',
+    'Exception.JKingWeb/Arsse/CLI/Exception.pidNotFile'                    => 'Specified PID file location "{pidfile}" must be a regular file',
+    'Exception.JKingWeb/Arsse/CLI/Exception.pidDirNotFound'                => 'Parent directory "{piddir}" of PID file does not exist',
+    'Exception.JKingWeb/Arsse/CLI/Exception.pidUnwritable'                 => 'Insufficient permissions to open PID file "{pidfile}" for writing',
+    'Exception.JKingWeb/Arsse/CLI/Exception.pidNotFile'                    => 'Specified PID file location "{pidfile}" must be a regular file',
 ];