If at any time, when you try to launch a php script it raises a fatal error with a message like
Fatal error: allowed memory size of X bytes exhausted, don't worry, the cause and solution are easy.
This error raises when you try to allocate more memory than it was configured in the configuration files.
In order to solve it, you can edit the php.ini client-side file (CLI or CGI) and search and increase the
memory_limit var or you can also modify it's value in real time throught the command line with the
-d flag. Something like
php -d memory_limit=512M script.php