I have shared hosting, and like many here I have problem running cron jobs because of the hosting provider settings for the path to the php binary, which right now I dont know. You could try "/usr/local/bin/php" or "php", but for me it didn't work. One reason might be that I have multiple websites under my main domain. Anyways, to update UNA you need the cron job running, so wanted to share how I managed to temporary fix the problem and easily update UNA from 9.0.0-RC4 to 9.0.0-RC5 to 9.0.0-RC6. By the way the path that was given by UNA's install was not compatible with my shared hosting and generated errors every minute in /periodic/error_log, by changing to /usr/local/bin/php from /usr/bin/php I got rid of the errors.
The way I made cron job run was easy and straight forward:
1. delete contents from these two folders:
2. disable in /periodic .htaccess by renaming it .htaccess_old
3. make account with cron-jobDOTorg fill the path to the cron.php in their app and set the intervals to run the file
4. Go to Studio/Dashboard and click on the update button in top left.
5. If you get message files have been modified and cannot update go to Studio/Settings/Site settings and check "Force auto-update, even if some files were modified". Go back to step 4 and update.
Now you have the latest update and can concentrate on fixing your cron jobs with your hosting provider.
If you find your cron job is not working you need to ask you hosting provider for the correct path to the php binary that runs cron. I am waiting on reply from the provider with details how to setup the cron job and if it is interesting I will add it here.