Using the Command Line Upgrade 
With vBulletin 5, you can run the upgrade script from the command line and remove the overhead of your browser and HTTP calls. The command line interface is designed to specifically help big boards with the upgrade process and to eliminate the time caused by HTTP interaction.

To run this interface, go to your install directory ( using the ‘cd’ command and execute:
php -f upgrade.php
If you are logged in as the root user, you will need to run the upgrade as the user that the webserver runs under. This will prevent permission problems from occurring later if you store CSS as files. Use this command:
sudo -u <user> php -f upgrade.php
Where <user> is the user that the webserver is run with. On most systems, this is the user nobody.

Your CLI version of PHP may not have been compiled with or configured to use the same modules as your web version. If you encounter problems in command line mode, switching to the web mode should be able to process through them. You can see your command line configuration by typing:
php -i > phpinfo.txt
You can then review the output in any text editor. You should inspect this configuration to make sure that it has mysql and/or mysqli available so you can connect to the database. You would also need to make sure that the command line version of PHP has XML support. If it does not, then you would need to run the XML imports from the Browser.
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