Wordpress quickly upgrade from command line
Wordpress has their own guide to upgrade wordpress, but in this post I will show you how I upgrade my all wordpress sites.
I using Ubuntu 14.04 server and I update wordpress from command line.
Backups
Before upgrade we backup our database and wordpress directory.
Download wordpress
Overwrite all new files
Remember change current directory to where wordpress located in your server.
Open http://your_domain.com/wp-admin/upgrade.php in a browser and run that script. It makes all needed database conversions. If something fails, you still have your backups in ~/backup/ directory.
Source
http://www.cyberciti.biz/tips/howto-upgrade-wordpress-from-linux-unix-shell-prompt.html