Register a new site in apache.

php-site.conf

# Crear nuevo archivo de configuración en /etc/apache2/sites-available/php-site.conf
<VirtualHost *:80>
    ServerName www.andrea.pos
    ServerAlias andrea.pos
    DocumentRoot /var/www/html/pos_andrea/posMain/application

    <Directory /var/www/html/pos_andrea/posMain/application>
        AllowOverride All
        Options FollowSymLinks MultiViews
        Order allow,deny
        Allow from all
        <IfModule mod_rewrite.c>
            RewriteEngine On
            RewriteCond %{REQUEST_FILENAME} !-f
            RewriteRule ^(.*)$ /app.php [QSA,L]
        </IfModule>
    </Directory>

    ErrorLog ${APACHE_LOG_DIR}/error_pos.log
    # Possible values include: debug, info, notice, warn, error, crit,
    # alert, emerg.
    LogLevel warn
    CustomLog ${APACHE_LOG_DIR}/access_pos.log combined
</VirtualHost>

# Agregar en /etc/hosts:
# 127.0.0.1   andrea.pos

# sudo a2ensite pos.conf
# sudo service apache2 reload