apt-get update non interactive

I'm trying to make an update fully non interactive.(on ubuntu 14.04.3 LTS) I thought it will be easy with this type of command:

export DEBIAN_FRONTEND=noninteractive
apt-get update && apt-get upgrade -q -y --force-yes && apt-get dist-upgrade -q -y --force-yes

but no... I always have a question like:

Configuration file '/etc/cloud/cloud.cfg' ==> Modified (by you or by a script) since installation. ==> Package distributor has shipped an updated version. What would you like to do about it ? Your options are: Y or I : install the package maintainer's version N or O : keep your currently-installed version D : show the differences between the versions Z : start a shell to examine the situation The default action is to keep your current version.
*** cloud.cfg (Y/I/N/O/D/Z) [default=N] ?

So do you known how I can accept the default value automatically ?

2 Answers

You need to pass some dpkg options to your commands, for instance:

export DEBIAN_FRONTEND=noninteractive
apt-get update && apt-get -o Dpkg::Options::="--force-confold" upgrade -q -y --force-yes && apt-get -o Dpkg::Options::="--force-confold" dist-upgrade -q -y --force-yes

On a side note, I would recommend using only dist-upgrade, you will eventually end up with broken dependencies if you use upgrade.

>= Apt 1.1

If you're using Apt 1.1 or above, --force-yes has been deprecated, so you've to use the options starting with --allow instead, e.g. --allow-downgrades, --allow-remove-essential, --allow-change-held-packages.

So the command is:

DEBIAN_FRONTEND=noninteractive \ apt-get \ -o Dpkg::Options::=--force-confold \ -o Dpkg::Options::=--force-confdef \ -y --allow-downgrades --allow-remove-essential --allow-change-held-packages

^{Note: Use --force-confold to keep old, and --force-confnew to keep new configs.}

Source: CFE-2360: Make apt_get package module version aware.

Related:

• 100% non-interactive Debian dist-upgrade
• How do I ask apt-get to skip any interactive post-install configuration steps?
• Non-interactive apt upgrade