I’m trying to update Piwik from the command line using this:
$ php /path/to/piwik/index.php – “module=CoreUpdater”
However nothing happens and it returns to the prompt immediately. Is this command still valid?
Yes, that command works.
Is the upgrade not done already? Do you use the correct path/to/piwik ?
No, the upgrade isn’t done already and yes I use the correct path 
Any way I can enable some debugging or let it be verbose?
Sorry I’m not sure, do you have any error logged in PHP CLI log? check the error logging is on in your etc/php5/cli/php.ini ?
Sorry, This is completely my fault since I haven’t read the manual right.
I thought this command was for upgrading but you need to upgrade first and then run this command which will only upgrade the database.
It all works fine now.