How to upgrade from Debian Wheezy to Debian Jessie (testing)

Users of any operating system sooner or later we are faced with the decision to update, and although it must be said that it is a process that has improved a lot in recent years, it can still cause problems from time to time. Perhaps that is why the Linux world has become so popular to use the rolling release distributions, which is how in the jargon those that never require updating are known.

Let's clarify this a bit since it actually does update but It is not necessary to install a new version of the operating system from scratch on top of the current one, but the changes are made little by little and continuously, since we have new versions for permanently installed applications and services. In this way we are not forced to carry out a big update every 6, 9 or 12 months (in which something can always go wrong) but rather we keep our system always updated.

In the case of Debian, one of the most prestigious Linux distributions, we have a rolling relese variant such as Debian Sid -the experimental branch- although users who need greater stability prefer to use Debiann testing, which in practice is almost rolling and which, contrary to what its name indicates, is very stable, to such an extent that it is taken as a starting point for other distros such as Linux Mint Debian Edition or Manjaro Linux.

One of the best things that Debian-based distros is the possibility to modify the repositories and easily change the version, so let's see how to go from Debian stable to Debian testing. Currently the first is called 'Wheezy' and the second 'Jessie' and they are called that way in the repositories, but when using generic names like stable y testing we are going to guarantee that our system always remains in testing, that is, when Jessie becomes the stable version we will automatically start to be in the next testing version, what as we learned recently it will be Debian Stretch.

The first thing we must do is edit the configuration file of the repositories, changing all references to stable or wheezy by testing:

# cp /etc/apt/sources.list{,.bak}
# sed -i -e 's/ \(stable\|wheezy\)/ testing/ig' /etc/apt/sources.list

Then you have to update the repositories:

# sudo apt-get update

Finally we will update the system, and to avoid inconveniences (for example in case of interruption) we will first download the packages and then install locally:

# apt-get --download-only dist-upgrade
# apt-get dist-upgrade

That's it, and when we restart our system we will be upgraded to Debian Jessie.