Please answer the following question: Information:  - PHP is a server-side scripting language designed primarily for web development but also used as a general-purpose programming language. Originally created by Rasmus Lerdorf in 1994, the PHP reference implementation is now produced by The PHP Development Team. PHP originally stood for "Personal Home Page", but it now stands for the recursive acronym "PHP: Hypertext Preprocessor".  - Drush is a computer software shell - based application used to control , manipulate , and administer Drupal websites . On the surface , drush is a tool for updating site modules , however Drush has a more comprehensive list of features .  - A blog (a truncation of the expression weblog) is a discussion or informational website published on the World Wide Web consisting of discrete, often informal diary-style text entries ("posts"). Posts are typically displayed in reverse chronological order, so that the most recent post appears first, at the top of the web page. Until 2009, blogs were usually the work of a single individual, occasionally of a small group, and often covered a single subject or topic. In the 2010s, "multi-author blogs" (MABs) have developed, with posts written by large numbers of authors and sometimes professionally edited. MABs from newspapers, other media outlets, universities, think tanks, advocacy groups, and similar institutions account for an increasing quantity of blog traffic. The rise of Twitter and other "microblogging" systems helps integrate MABs and single-author blogs into the news media. "Blog" can also be used as a verb, meaning "to maintain or add content to a blog".  - Drupal , a free and open source content-management framework written in PHP and distributed under the GNU General Public License, provides a back-end framework for at least 2.2% of all Web sites worldwide  ranging from personal blogs to corporate, political, and government sites. Systems also use Drupal for knowledge management and for business collaboration.    What entity does 'drush' has the relation 'programming language' with?
Answer:
php