Every time I use odoo posbox image on the raspberry, I can't use the sudo command, did I miss something?
In your picture it is the Pi part of the command that bash is complaining about.
sudo command gives the current user root privileges and does not need to be told what user you are. You can state the user with
sudo -u user If you do not want to be root (for example www-data).
One minor point - if you are using the command line to update, it’s now better to use apt than apt-get as it gives more feedback. apt-get is now being used for automated updates.
A simple way to bring the system up to date is:
sudo apt update && sudo apt -y upgrade
This updates the repository list and if (and ONLY if) that has run fine, downloads and automatically installs the latest versions from the repository.