Do not fear the shell! If you have SSH enabled web hosting, you should use it to upgrade your WordPress installation. Believe it or not, it only consists of a few steps (note that the instructions below assume that WP is installed in ~/public_html/):

  1. Login via SSH to your host
  2. Go to a temporary directory: cd /tmp
  3. Grab the latest WP archive: wget http://wordpress.org/latest.tar.gz
  4. Extract the archive contents: tar xzf latest.tar.gz
  5. You should now see a wordpress directory extracted in the currect location, go in it: cd wordpress/
  6. Copy the default themes to your WP install’s wp-content/themes directory: cp -R wp-content/themes/* ~/public_html/wp-content/themes/
  7. Copy the bundled plugins (Hello Dolly and Akismet) to your WP install’s wp-content/plugins directory: cp -R wp-content/plugins/* ~/public_html/wp-content/plugins/
  8. Delete the wp-content directory: rm -rf wp-content/
  9. Copy all other files and directories of the new version onto the WP installation path (overwriting the older ones)cp -R * ~/public_html/

To complete the process, run the WP upgrade script at http://yoursite/wp-admin/upgrade.php.

That’s it! Enjoy your upgraded WP!