how do i know i need a reboot after a console based "upgrade"?

[Gabriel Dragffy]

Tomoki Taniguchi wrote:
> when updating a system with the newest packages using the desktop
> tools like synaptic,
> if a package is upgraded that requires a reboot to take effect,
> there is a little icon that shows up on the upper panel to let me know
> i need to reboot.
> 
> 
> on a server system,  if i do a "sudo apt-get upgrade" or "sudo aptitude upgrade"
> is there anyway to know i need a reboot?
> 
> is there a file that is flagged?
> or does the upgrade process return something that i can catch using grep?
> or better still is there a way to tell apt-get or aptitude to reboot the system
> after an upgrade when necessary?
> 
> TIA,
> Tomoki Taniguchi
> 

AFAIK if you do 'upgrade' then you shouldn't need to restart for the 
changes to take effect. If you do a 'dist-upgrade' then generally you 
will need to restart for the changes to take effect. I'm not aware of 
anything else that lets you know.