- How do you actually do the restart (I'm a beginner and using 12.04.1 LTS)?
- Should I always restart the system when prompted to?
- Does restarting the system affect access to it via SSH or there any other caveats one needs to think about before doing this?
Should I restart when prompted?
Yes, you should. For most cases, a restart is required when an update to the Linux kernel has been installed. These updates are usually security updates, and then only come into effect after a reboot. Updates to normal applications such as Firefox come into effect after you restart the program. Firefox should prompt you to do this automatically, but other programs may not, so it's something to bear in mind.
How to restart:
To restart the computer in Ubuntu 12.04, click the power icon in the upper right corner of the screen, and select "Shut down...". In the dialog that appears, a "Restart" button should be visible. In Ubuntu 12.10, the restart option appears in the power menu directly.
To restart from the command-line, run this command:
The downsides of restarting:
On the whole, restarting is a very safe operation, and I would not consider it in any way unsafe. Of course, when you restart the computer, you lose all the information in RAM, so make sure you save all open documents and files before shutting down your computer. While you are restarting, your computer will of course be offline for a few minutes. If you're running a server, it will be down for a few minutes. If you have an open SSH session, it will be terminated.
1- How to restart $ sudo reboot OR $ sudo init 6
2- yes as its most probably a security updates.
3- nothing will affect ssh connectivity after restart.
Always try to Restarting the pc after ubuntu updates, install drivers and some application that wants to restart the OS(ubuntu).
when new updates are installed or driver is installed these wants to restart the OS for working performance and properly use.
Normal application or package don't need to restart the OS after installed.
1- Another option is using sudo shutdown -r now
2- If prompted, you should do so; as system have things need to be applied (most common if you choosed to download and install updates automatically, or you have changed something youself that requires a reboot to apply changes to your system).
3-SSH will definately be affected on a reboot and it will be terminated. I may suggest Putty as it will give an option on its context menu to reconnect the session.