I have always been running the following command to update via terminal my machines:
sudo apt-get update && sudo apt-get upgrade -y
But the other day, right after having finished installing some updates, the Update Manager popped up asking me to install some updates. I was puzzled as I have always thought the two were equivalent. I tried running the terminal command again: no updates. Then tried pressing the "Check" button on Update Manager: again some updates were available.
My conclusion is that the command above is not equivalent to the Update Manager, as I have always thought. So, what is the true equivalent terminal command of Update Manager?