How can I make all installed packages up-to-date?
yum -y update (Say "yes" to everything - run unattended)
I have found the GUI (Software Update) doesn't work. Maybe it needs to checking occasionally.
dnf -y update (Say "yes" to everything)
sudo apt-get upgrade
sudo apt-get -y upgrade (Say "yes" to everything)
If you prefer a GUI, you can search for "Updater" and click on "Software Updater"
env ASSUME_ALWAYS_YES=YES pkg upgrade (Says "yes" to everything)
FreeBSD on two lines (saying "yes" to everything)
Do not use `pkg update` which just updates the repositories.