1. Install Concrete5

2. Install OCI8 dependencies on Concrete5 server

sudo apt-get install build-essential php5-dev php-pear libaio1

3. Edit /etc/environment to add some system-wide environment vars to support OCI8

LD_LIBRARY_PATH="/usr/local/lib/instantclient_11_2"
TNS_ADMIN="/usr/local/lib/instantclient_11_2"
ORACLE_BASE="/usr/local/lib/instantclient_11_2"
ORACLE_HOME="/usr/local/lib/instantclient_11_2"

4. Obtain Oracle Instant Client by going to http://www.oracle.com/ , select Downloads, select Instant Client, select Instant Client for Linux x86-64 and then download instantclient-basic-linux.x64-11.2.0.3.0.zip and instantclient-sdk-linux.x64-11.2.0.3.0.zip save them somewhere like /tmp/

5. Install OCI

cd /usr/local/lib/
unzip /tmp/instantclient-basic-linux.x64-11.2.0.3.0.zip    
unzip /tmp/instantclient-sdk-linux.x64-11.2.0.3.0.zip
cd instantclient_11_2
ln -s libclntsh.so.11.1 libclntsh.so
pecl install oci8

When prompted type in

instantclient,/usr/local/lib/instantclient_11_2

Create file /etc/php5/conf.d/oci8.ini and place the following in it:

extension=oci8.so

6. Restart Apache2

service apache2 restart

7. Create /var/www/phpinfo.php and place inside the following:

<?php echo phpinfo() ?>

You should now have OCI8 installed. Browse to your http://your.site/phpinfo.php and verify that you see a section titled OCI8.

8. Create a file in /var/www/concrete5.5.1 named concrete5cli.php inside place the following:

<?php
# concrete5cli.php
# Originally obtained from:
# http://www.concrete5.org/community/forums/documentation_efforts/how-to-running-concrete5-from-php-command-line/
define('DIR_BASE','.');
define('C5_ENVIRONMENT_ONLY', true);
require_once('config/site.php');
if ( !defined('REDIRECT_TO_BASE_URL') ){
  define('REDIRECT_TO_BASE_URL', false);
}
if ( defined('DIRNAME_APP_UPDATED') ){
  $GLOBALS['APP_UPDATED_PASSTHRU'] = true;
  require('updates/' . DIRNAME_APP_UPDATED . '/concrete/dispatcher.php');
}
else{
  require('index.php');
}
?>

9. Create a file in /var/www/concrete5.5.1/ named dbtest.php and place inside:

    <?php
    # dbtest.php
    require('concrete5cli.php');
    $host = "db server hostname or IP";
    $port = "db port";
    $sid  = "db name";
    $connect_string = "(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=$host)(PORT=$port)) (CONNECT_DATA=(SID=$sid)))";
    $user = "db username";
    $        pass = "db password";
    $db = Loader::db($connect_string,$user,$pass);
    $result = $db->Execute('show tables');
    if ($result === false) die("failed");
    while ($array = $result->FetchRow()) {
        print_r($array);
    }
    exit;
    ?>

10. Run php script from command line, it should connect to your Oracle database and list all tables available.

    php ./dbtest.php