I run an increasing number of WordPress sites, as well as several for clients - and logging in to perform upgrades is becoming tiresome. I'm looking for a means of automating the process, preferably from a single command line script - and upgrading all the sites in one fell swoop.
My ideal would be to hook into the very good automatic backup that's built into WordPress, and trigger it from the server for all 30 sites. That would cover file updating and then the database.
All the websites I have backup every 24 hours so backing up before the upgrade starts isn't a priority (but you can never have too many backups!) however, a means to determine whether a site has broken would be another interesting feature.
Assuming that I can't hook directly into the built in backup, I found this which more or less operates in the way I was thinking, but doesn't perform the database upgrades. I understand that this could potentially leave the website vulnerable until an administrator logs in and performs the update (which could be up to 72 hours).
I'm also familiar with the concept of using SVN and GIT to perform the updates, but if I were to move down this route I need to find a reliable way of ensuring that a) /wp-content files aren't damaged and b) file permissions for the whole site are conserved (if the script is run as the root user).