For some of the basic packaging operations, apt and yum are basically identical.
These are "similar" operations, but there are some differences in how they act.
These two are similar:
apt-get --simulate upgrade
yum check-update
I guess this one-liner can be used to display a notification if there are updates.
apt-get --simulate upgrade | grep "The following packages will be upgraded:"; if [ "${PIPESTATUS[1]}" -eq "0" ]; then notify-send -i /usr/share/icons/gnome/32x32/status/software-update-available.png -u normal Updates "There are updates available"; fi
Or in a script
#!/bin/bash
apt-get --simulate upgrade | grep "The following packages will be upgraded:"
if [ "${PIPESTATUS[1]}" -eq "0" ]; then
notify-send -i /usr/share/icons/gnome/32x32/status/software-update-available.png -u normal Updates "There are updates available."
fi
The icon in the notification area is a tricky part.
Edit: This is not practical because you have to do sudo apt-get update first