title: Parse error when running cron job in Laravel 5.5
body: <p>I've updated my crontab using <code>crontab -e</code> to run the Laravel task scheduler every minute. It wasn't working so I set it to add its output to a log file, like so:</p>
  
  <pre><code>* * * * * php /path/to/project/artisan schedule:run &gt;&gt; cron_output.log 
  </code></pre>
  
  <p>Now the log contains the following message:</p>
  
  <pre><code>Parse error: parse error in /path/to/project/vendor/laravel/framework/src/Illuminate/Foundation/helpers.php on line 233
  </code></pre>
  
  <p>This is the method it points to (I've commented next to line 233):</p>
  
  <pre><code>function cache()
      {
          $arguments = func_get_args();
  
      if (empty($arguments)) {
          return app('cache');
      }
  
      if (is_string($arguments[0])) {
          return app('cache')-&gt;get($arguments[0], $arguments[1] ?? null);    //line 233
      }
  
      if (! is_array($arguments[0])) {
          throw new Exception(
              'When setting a value in the cache, you must pass an array of key / value pairs.'
          );
      }
  
      if (! isset($arguments[1])) {
          throw new Exception(
              'You must specify an expiration time when setting a value in the cache.'
          );
      }
  
      return app('cache')-&gt;put(key($arguments[0]), reset($arguments[0]), $arguments[1]);
  }
  </code></pre>
  
  <p>I don't understand this issue, as Laravel runs normally otherwise. PHP version is 7.2 (based on <code>php -v</code> and also <code>phpinfo()</code>) so that shouldn't be a problem. Is it possible that somehow the crontab is using an older version of PHP? If so how do I fix this? Any other ideas?</p>