A condenced howto to install ioncube loaders on Centos 6.
cd /usr/src; wget http://downloads2.ioncube.com/loader_downloads/ioncube_loaders_lin_x86-64.tar.gz; tar -xvf ioncube_loaders_lin_x86-64.tar.gz; cd ioncube; cp ioncube_loader_lin_* /usr/local/lib/; echo "zend_extension = /usr/local/lib/ioncube_loader_lin_5.3.so"; /etc/php.d/ioncube.ini; service httpd restart; cd ~; rm -Rf /usr/src/ioncube*;
You can check if installed by: php -v
PHP 5.3.3 (cli) (built: Jul 3 2012 16:53:21) Copyright (c) 1997-2010 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies with the ionCube PHP Loader v4.4.1, Copyright (c) 2002-2013, by ionCube Ltd., and with Zend Guard Loader v3.3, Copyright (c) 1998-2010, by Zend Technologies