If you've installed php5-fpm, run the following Unix command to see the PHP engine's version:
$ php5-fpm --version PHP 5.5.9-1ubuntu4.9 (fpm-fcgi) (built: Apr 17 2015 11:44:58) Copyright (c) 1997-2014 The PHP Group Zend Engine v2.5.0, Copyright (c) 1998-2014 Zend Technologies with Zend OPcache v7.0.3, Copyright (c) 1999-2014, by Zend TechnologiesAs you can see, the command to show the PHP version is php5-fpm --version. My PHP version is 5.5.9.
If you are on an older PHP platform, you can run php --version or /usr/bin/php5-cgi v to find out your PHP CGI's version, as shown below.
$ php --version PHP 5.3.2-1ubuntu4.20 with Suhosin-Patch (cli) (built: Jul 15 2013 17:15:36) Copyright (c) 1997-2009 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies $ /usr/bin/php5-cgi v Status: 404 Not Found X-Powered-By: PHP/5.3.2-1ubuntu4.20 Content-type: text/html No input file specified. $As you can see the PHP version is 5.3.2-1ubuntu4.20.
If your php5-cgi is installed elsewhere you need to use that location instead.
Questions? Let me know!