Currently running Squeeze and wanted to learn some programming (Just a book on python3)
#aptitude search python3.1 - returns nothing.


Googled and understand that python3.1 is in experimental and read about apt-pinning (http://jaqque.sbih.org/kplug/apt-pinning.html). Added the unstable and experimental repository and the /etc/atp/preferences file.

#aptitude search python3.1 returns a list of apps now - good.


Now,
#aptitude install python3.1 - allows me to install python3.1
#aptitude -t experimental install python3.1 - also allows installing of python3.1


Q1. As the above 2 command gives the identical outcome, what is the difference between the 2 command above?

Q2. Assuming I keep the repositories, in future how would I know if the packages I install is from which repositories?

The reason is your preferences file. You give weighted preferences (presumably higher for squeeze than experimental). Now you want to install python3.1 so the system first looks in the squeeze repos and can't find it. Then it tries (as per your preferences file) the experimental repos and there it is. You would only see a difference in behaviour of your two commands (with or without the -t experimental) if the package you want to install has the same name in both repos.

Hope that's clear.
Cheers,
jdk

Hi jdk, thanks for replying.

So, my perception that experimental will be triggered only with the -t experimental option is wrong.

Q1. Apt-get (aptitude) will install whatever is available in any of the repositories listed in source.list - preference given to the higher weighted repositories?

The -t experimental option will force an install from the experimental repositories even if the package is available in other repositories.


Q2. If I am to do a apt-get upgrade, does it mean that I will be upgrading from SID instead of Testing?


Q3. If you allow me to sidetrack a little. Assuming that the mirror that I've configured for testing is

deb http://http.us.debian.org/debian/ testing main contrib non-free

Am I right to safely assume that the unstable and experimental repository will be:

deb http://http.us.debian.org/debian/ unstable main contrib non-free
deb http://http.us.debian.org/debian/ experimental main contrib non-free


Thanks in advance for the help

That's correct.

correct.


No, you will be upgrading whatever version is currently installed. If you installed a testing version of program X and a later testing
version is now available that will be installed. You can see that this must work this way. Otherwise you'd wind up with a pure Sid installation.

I'm sure that's true for unstable. That's what I use. You'd have to check about experimental yourself.
you're quite welcome
jdk

You might take a look at Howto: Set up and Maintain a Mixed Testing/Unstable System - http://forums.debian.net/viewtopic.php?f=16&t=15612

After reading all your comments and link http://forums.debian.net/viewtopic.php?t=15612

I'll remove the /etc/apt/prefereneces and create /etc/apt/apt.conf with contents
Installation of python3 will be by the command

The repositories that I will be using will be :

deb http://ftp.jaist.ac.jp/pub/Linux/Debian/ testing main contrib non-free
deb http://ftp.jaist.ac.jp/pub/Linux/Debian/ unstable main contrib non-free
deb http://ftp.jaist.ac.jp/pub/Linux/Debian/ experimental main contrib non-free
deb http://security.debian.org/ squeeze/updates main contrib non-free




Thanks again for the help