Upgrade from moodle 1.8 to 1.9 (with Nwiki upgrade)
A very quick how to to upgrade moodle 1.8 to moodle 1.9 (with Nwiki upgrade from 1.8 to 1.9):
1. Stop you moodle 1.8 (mantainence mode)
2. Copy your moodle BD (ispconfig is great for this) to a new one (here is dbmoodle19)
3. cp /home/public_html/moodle18 /home/public_html/moodle19
4. cd /home/public_html/moodle19 | wget http://download.moodle.org/stable19/moodle-weekly-19.tgz
5. tar xvzf moodle-weekly-19.tgz
6. cp moodle/* . -a
7. rm moodle -Rf
8. Review your config.php: vim /home/public_html/moodle19/config.php (dbusers | dbtables | urls | paths)
9. Visit your new Moodle to start the upgrade to 1.9 process: http://www.yoursite.net/moodle19
10. Follow the wizard and congratulations: your moodle is now 1.9 !!
11. Download nWiki 1.9 and upload to your server: http://morfeo.upc.es/crom/mod/resource/view.php?id=268
12. unzip & copy to your moodle root.
13. Visit your moodle notifications page and follow the wizard.
14. Congratulations your Nwiki is also updated.