(PHP) How to obtain the filename (or file path) when a script is executed as a cron job?

I have a PHP script th开发者_StackOverflow社区at executes perfectly when called via the browser. It fails, however, when called as a cron job. The failure is because the script needs to access its own filename, which I do via $thefilepath = $_SERVER['REQUEST_URI']. Unfortunately, the $_SERVER['REQUEST_URI'] variable isn't populated when the file is called as a cron job. (I've similarly failed with trying $_SERVER['PHP_SELF']).

In case anyone is interested, the script needs to access its own filename because the filename contains an integer (for example, filename = myfile4.php) that is used in the calculation of a subset of rows in a database table. More specifically, myfile4.php takes rows with IDs from, say, 40-49, whereas myfile5.php takes rows with IDs from 50-59, etc.

So, my question is, given that $_SERVER['REQUEST_URI'] and $_SERVER['PHP_SELF'] fail to provide the filename (or filepath) for use in a cron job, can anyone please suggest an alternative method of accessing a script's own filename within this cron execution context?

Thank you!

Use __FILE__ or __DIR__ or dirname(__FILE__) http://www.php.net/manual/en/language.constants.predefined.php

$argv[0] will always contain the name of the script: http://www.php.net/manual/en/reserved.variables.argv.php