I was scheduling an apt-get update && apt-get –y upgrade on a Debian 8 box and the process stopped waiting for keyboard input showing the change logs for CA-Certificates.

it had actually started VI and was displaying a text file.  This would stop the automatic update process.

To prevent this I ran apt-get –y remove apt-listchanges

References:

https://serverfault.com/questions/835303/is-there-a-way-to-make-apt-get-upgrade-not-show-changelogs