I installed lampp, and then i downloaded newest version of "joomla" and i unpacked it to

/var/www/joomla/

then i went to my browser and i opened this link :
localhost/joomla
so it opened the installation of joomla, then i chose language and went to the next page, in that page it showed me that the "output buffering is on and it should be off so i run this command on the terminal:

sudo gedit /etc/php5/apache2/php.ini

i opened php.ini and then i found this :

output buffering: 4096

i changed it to :

output buffering: off

then i saved php.ini and i refreshed the installation of joomla but output buffering was still on.
how can i turn this off?