I am continually forgetting and having to search for the file that records whether the system needs a reboot (of course, not I've written this up I'll remember forever :-).
$ cat /var/run/reboot-required
If the file is there then its contents is:
*** System restart required ***
and I know it needs a reboot. In addition, /var/run/reboot-required.pkgs lists the packages that necessitate the reboot.
This is handled by the update-notifier-common
package that is installed by default on Ubuntu (not sure about Debian).
Would be great to have
$ wajig reboot-required
*** System restart required ***
linux-image-3.13.0-37-generic
dbus
$ wajig reboot-required
No reboot required at this time.
$