Please notice that white space is important in this line:
php -f /path/to/your/php/script.php
There is a space between php and -f and space between -f and path to the php file.
Since many hosts have different set ups (some worse than others) you might have to experiment to figure out the file path. You could try a php script to help you...place it in same directory as the file.php script, and have it print $_SERVER['PATH_TRANSLATED'] to the screen. That should help you figure out file system path to your scripts.
//dump.php
print $_SERVER['PATH_TRANSLATED'];
prints to screen the file system path to dump.php:
/home/tom/public_html/freelance/battery/dump.php