diff --git a/src/Application.php b/src/Application.php
index f60c7486..5430ac81 100644
--- a/src/Application.php
+++ b/src/Application.php
@@ -19,6 +19,7 @@
 use Cake\Console\CommandCollection;
 use Cake\Core\ConsoleApplicationInterface;
 use Cake\Upgrade\Command\FileRenameCommand;
+use Cake\Upgrade\Command\LinterCommand;
 use Cake\Upgrade\Command\RectorCommand;
 use Cake\Upgrade\Command\UpgradeCommand;
 
@@ -51,6 +52,7 @@ public function console(CommandCollection $commands): CommandCollection
         $commands->add('upgrade', UpgradeCommand::class);
         $commands->add('upgrade file_rename', FileRenameCommand::class);
         $commands->add('upgrade rector', RectorCommand::class);
+        $commands->add('linter', LinterCommand::class);
 
         return $commands;
     }
diff --git a/src/Command/Helper/ProgressHelper.php b/src/Command/Helper/ProgressHelper.php
new file mode 100644
index 00000000..2c8b5ab6
--- /dev/null
+++ b/src/Command/Helper/ProgressHelper.php
@@ -0,0 +1,163 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ * @link          https://cakephp.org CakePHP Project
+ * @since         3.1.0
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
+namespace Cake\Upgrade\Command\Helper;
+
+use Cake\Console\Helper;
+use InvalidArgumentException;
+
+/**
+ * Create a progress bar using a supplied callback.
+ *
+ * ## Usage
+ *
+ * The ProgressHelper can be accessed from shells using the helper() method
+ *
+ * ```
+ * $this->helper('Progress')->output(['callback' => function ($progress) {
+ *     // Do work
+ *     $progress->increment();
+ * });
+ * ```
+ */
+class ProgressHelper extends Helper
+{
+    /**
+     * Default value for progress bar total value.
+     * Percent completion is derived from progress/total
+     */
+    protected const DEFAULT_TOTAL = 100;
+
+    /**
+     * Default value for progress bar width
+     */
+    protected const DEFAULT_WIDTH = 80;
+
+    /**
+     * The current progress.
+     *
+     * @var float|int
+     */
+    protected float|int $_progress = 0;
+
+    /**
+     * The total number of 'items' to progress through.
+     *
+     * @var int
+     */
+    protected int $_total = self::DEFAULT_TOTAL;
+
+    /**
+     * The width of the bar.
+     *
+     * @var int
+     */
+    protected int $_width = self::DEFAULT_WIDTH;
+
+    /**
+     * Output a progress bar.
+     *
+     * Takes a number of options to customize the behavior:
+     *
+     * - `total` The total number of items in the progress bar. Defaults
+     *   to 100.
+     * - `width` The width of the progress bar. Defaults to 80.
+     * - `callback` The callback that will be called in a loop to advance the progress bar.
+     *
+     * @param array $args The arguments/options to use when outputting the progress bar.
+     * @return void
+     */
+    public function output(array $args): void
+    {
+        $args += ['callback' => null];
+        if (isset($args[0])) {
+            $args['callback'] = $args[0];
+        }
+        if (!$args['callback'] || !is_callable($args['callback'])) {
+            throw new InvalidArgumentException('Callback option must be a callable.');
+        }
+        $this->init($args);
+
+        $callback = $args['callback'];
+
+        $this->_io->out('', 0);
+        while ($this->_progress < $this->_total) {
+            $callback($this);
+            $this->draw();
+        }
+        $this->_io->out('');
+    }
+
+    /**
+     * Initialize the progress bar for use.
+     *
+     * - `total` The total number of items in the progress bar. Defaults
+     *   to 100.
+     * - `width` The width of the progress bar. Defaults to 80.
+     *
+     * @param array<string, mixed> $args The initialization data.
+     * @return $this
+     */
+    public function init(array $args = [])
+    {
+        $args += ['total' => self::DEFAULT_TOTAL, 'width' => self::DEFAULT_WIDTH];
+        $this->_progress = 0;
+        $this->_width = $args['width'];
+        $this->_total = $args['total'];
+
+        return $this;
+    }
+
+    /**
+     * Increment the progress bar.
+     *
+     * @param float|int $num The amount of progress to advance by.
+     * @return $this
+     */
+    public function increment(float|int $num = 1)
+    {
+        $this->_progress = min(max(0, $this->_progress + $num), $this->_total);
+
+        return $this;
+    }
+
+    /**
+     * Render the progress bar based on the current state.
+     *
+     * @return $this
+     */
+    public function draw()
+    {
+        $numberLen = strlen(' 100%');
+        $complete = round($this->_progress / $this->_total, 2);
+        $barLen = ($this->_width - $numberLen) * $this->_progress / $this->_total;
+        $bar = '';
+        if ($barLen > 1) {
+            $bar = str_repeat('=', (int)$barLen - 1) . '>';
+        }
+
+        $pad = ceil($this->_width - $numberLen - $barLen);
+        if ($pad > 0) {
+            $bar .= str_repeat(' ', (int)$pad);
+        }
+        $percent = ($complete * 100) . '%';
+        $bar .= str_pad($percent, $numberLen, ' ', STR_PAD_LEFT);
+
+        $this->_io->overwrite($bar, 0);
+
+        return $this;
+    }
+}
diff --git a/src/Command/LinterCommand.php b/src/Command/LinterCommand.php
new file mode 100644
index 00000000..1463172e
--- /dev/null
+++ b/src/Command/LinterCommand.php
@@ -0,0 +1,154 @@
+<?php
+declare(strict_types=1);
+
+namespace Cake\Upgrade\Command;
+
+use Cake\Console\Arguments;
+use Cake\Console\BaseCommand;
+use Cake\Console\ConsoleIo;
+use Cake\Console\ConsoleOptionParser;
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
+use RegexIterator;
+use SplFileInfo;
+use Symfony\Component\Process\Process;
+
+class LinterCommand extends BaseCommand
+{
+    protected static array $defaultDirectories = [
+        'src/',
+        'config/',
+        'templates/',
+        'tests/',
+    ];
+
+    /**
+     * The name of this command.
+     *
+     * @var string
+     */
+    protected string $name = 'linter';
+
+    /**
+     * Get the command description.
+     *
+     * @return string
+     */
+    public static function getDescription(): string
+    {
+        return 'Check PHP files using PHP linter.';
+    }
+
+    /**
+     * Hook method for defining this command's option parser.
+     *
+     * @param \Cake\Console\ConsoleOptionParser $parser The parser to be defined
+     * @return \Cake\Console\ConsoleOptionParser The built parser.
+     */
+    public function buildOptionParser(ConsoleOptionParser $parser): ConsoleOptionParser
+    {
+        $dirs = [];
+        foreach ($this->defaultDirectories() as $dir) {
+            $dirs[] = '`' . $dir . '`';
+        }
+
+        $help = 'The path (or comma separated paths) to the file or directory to check.';
+        $help .= ' If not provided, defaults to checking common directories ' . implode(', ', $dirs) . '.';
+
+        return parent::buildOptionParser($parser)
+            ->addArgument('path', [
+                'help' => $help,
+                'default' => null,
+                'required' => false,
+            ])
+            ->setDescription(static::getDescription());
+    }
+
+    /**
+     * Implement this method with your command's logic.
+     *
+     * @param \Cake\Console\Arguments $args The command arguments.
+     * @param \Cake\Console\ConsoleIo $io The console io
+     * @return int The exit code
+     */
+    public function execute(Arguments $args, ConsoleIo $io): int
+    {
+        $directories = $args->getArgument('path') ?: $this->defaultDirectories();
+        if (is_string($directories) && str_contains($directories, ',')) {
+            $directories = explode(',', $directories);
+        }
+
+        $result = static::CODE_SUCCESS;
+        $errors = [];
+        foreach ((array)$directories as $directory) {
+            if (!file_exists($directory)) {
+                $io->warning('Does not exist: ' . $directory . ' - skipping.');
+
+                continue;
+            }
+
+            $io->out('Checking ' . (is_file($directory) ? 'file' : 'directory') . ': ' . $directory);
+            if (is_file($directory)) {
+                $phpFiles = [
+                    new SplFileInfo($directory),
+                ];
+            } else {
+                $files = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($directory));
+                $phpFiles = new RegexIterator($files, '/\.php$/');
+            }
+
+            $fileCount = iterator_count($phpFiles);
+            $io->helper('Progress')->init(['total' => $fileCount]);
+            $io->out('', 0);
+
+            /** @var \SplFileInfo $file */
+            foreach ($phpFiles as $file) {
+                $io->verbose('Checking ' . $file->getPathname());
+
+                $command = 'php -l ' . $file->getPathname();
+                $process = Process::fromShellCommandline($command);
+                $process->run();
+
+                if ($process->getExitCode() !== static::CODE_SUCCESS) {
+                    $errors[] = $file->getPathname() . ': ' . $process->getErrorOutput();
+                    $result = self::CODE_ERROR;
+
+                    continue;
+                }
+
+                $io->helper('Progress')->increment();
+                $io->helper('Progress')->draw();
+            }
+
+            $io->out('');
+        }
+
+        if ($errors) {
+            $io->err($errors);
+        }
+
+        if ($result === self::CODE_SUCCESS) {
+            $io->success('All files are valid.');
+        } else {
+            $io->error('Some files have errors. Please check the output above.');
+        }
+
+        return $result;
+    }
+
+    /**
+     * @return array<string>
+     */
+    protected function defaultDirectories(): array
+    {
+        $result = [];
+        foreach (static::$defaultDirectories as $directory) {
+            if (!is_dir($directory)) {
+                continue;
+            }
+            $result[] = $directory;
+        }
+
+        return $result;
+    }
+}
diff --git a/tests/TestCase/Command/LinterCommandTest.php b/tests/TestCase/Command/LinterCommandTest.php
new file mode 100644
index 00000000..91191f22
--- /dev/null
+++ b/tests/TestCase/Command/LinterCommandTest.php
@@ -0,0 +1,61 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ * @link          https://cakephp.org CakePHP(tm) Project
+ * @since         6.0.0
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
+namespace Cake\Upgrade\Test\TestCase\Command;
+
+use Cake\Console\TestSuite\ConsoleIntegrationTestTrait;
+use Cake\Upgrade\Test\TestCase\TestCase;
+
+class LinterCommandTest extends TestCase
+{
+    use ConsoleIntegrationTestTrait;
+
+    /**
+     * setup method
+     *
+     * @return void
+     */
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->configApplication('\Cake\Upgrade\Application', []);
+    }
+
+    /**
+     * @return void
+     */
+    public function testLinterSuccess()
+    {
+        $this->exec('linter');
+
+        $this->assertExitSuccess();
+        $this->assertOutputContains('All files are valid.');
+    }
+
+    /**
+     * @return void
+     */
+    public function testLinterFail()
+    {
+        mkdir(TMP . 'linter', 0777, true);
+        file_put_contents(TMP . 'linter/BrokenExample.php', '<?php class X }');
+        $this->exec('linter tmp/linter/ -v');
+
+        $this->assertExitError();
+        $this->assertErrorContains('Some files have errors.');
+    }
+}