Pi-Update

Before you start... FYI... Check available space!!

When running sudo apt-get upgrade, it will show how much data will be downloaded and how much space it will take up on the SD card. It's worth checking with df -h that you have enough disk space free, as unfortunately apt will not do this for you. Also be aware that downloaded package files (.deb files) are kept in /var/cache/apt/archives. You can remove these in order to free up space with sudo apt-get clean.

To upgrade installed packages

$ sudo apt-get update

$ sudo apt-get upgrade

Reboot after the updates

$ sudo sync

$ sudo reboot

To upgrade to the latest Debian distribution

$ sudo apt-get dist-upgrade

Only to be performed when system requests it

Update firmware

$ sudo rpi-update