Why does apt-get install throw "Extracting templates from packages" to stderr?

Question

When I run apt-get install, even in quiet mode -qq and by redirecting stdout to /dev/null, I still have the following message displayed in stderr :

Extracting templates from packages: 100%

Why is this message in stderr ?

Midvictorian

Answer 1

it's not apt that emits this message but dpkg-preconfigure, a tool that is used by apt, but otherwise follows its own rules: obviously these rules do not include honoring flags passed to apt.

Maxantia

I know, I'm too late to the party, but anyway... Is it possible to push all such messages (the ones coming from tools triggered by apt, or any other package for that matter) to a custom function? – Junejuneau