So I tried to use the simple background update (third option at http://tt-rss.org/redmine/projects/tt-rss/wiki/UpdatingFeeds) but a) it triggers an authentication request from my company’s firewall every time and b) as the feeds I am looking at only keep the 20 most recent items, I do need to update pretty regularly, not only when my browser is open.
So I set up option 2, which is the periodical updating from crontab. On Tiny Core Linux, I first had to update /usr/local/lib/php.ini with the right location for the mysql.so extension, which is not the /usr/local/lib/php/extensions default but /usr/local/lib/php/extensions/no-debug-non-zts-20090626 (not actually sure why?) in order to allow the php executable to run without apache.
Then, the command to enter in the crontab to run the job every 15 mins (it doesn’t allow you running it as root) is:
*/15 * * * * su tc -c “/usr/local/bin/php /usr/local/apache2/htdocs/rss/update.php -feeds -quiet”