Pinning syntax?
 

When pinning how can you work out from the url of the repository what should go in the o= and a= sections?

for example what should I put for

deb mentors.debian.net/debian/ unstable main contrib non-free

Package: *
Pin: release o= ,a=
Pin-Priority: 300

Also pin-priorities greater than 1000 will be downgraded, to are there any other special numbers?

Thanks.

This document describes the whole concept of Apt-pinning well: http://jaqque.sbih.org/kplug/apt-pinning.html


I've never used the o= one in such. And as the value for the a= one, it is typically one of: stable, testing, unstable, experimental, woody, sarge, sid.

I want to use pinning because I’m going to add some unofficial third party repositories. I only want them to be used if the package can’t be found in the main Debian ones.

I think the o= bit has to be used for this but the link you posted seems to explain pinning the official repositories only.