Debian – How to tell apt to use the latest package by default

aptdebian

I put jessie-backports in my /etc/apt/sources.list, but it seems that apt will not automatically use the packages from backports but older packages.

However, if I use apt-cache show to check the version it shows the latest, and I am able to use apt install xxx=<latest-version> to install it.

How to tell apt always use the latest package by default?

Best Answer

As @cutrightjm has mentioned apt-pinning is the solution.

If you create a file /etc/apt/preferences.d/backports with the following content

Package: *
Pin: release a=stretch-backports
Pin-Priority: 800

apt will always install packages from stretch-backports, except when you pin another package source with a priority higher than 800.

If you want to see all available versions of a package, their priority and which one will be installed, you can use apt-cache policy <packagename>.

Related Solutions

APT – How Does apt-get Deal with Multiple Sources

APT will always install the latest version that isn't excluded by preferences. Preferences are indicated in the file /etc/apt/preferences (and in files under /etc/apt/preferences.d).

Some repositories have a configuration that prevents their packages from being installed automatically. For example, the Debian backports have release files (which you can see in /var/lib/apt/lists) that contain

NotAutomatic: yes
ButAutomaticUpgrades: yes

If you have multiple sources for the exact same package (i.e. same package name, same version number), then APT downloads from the first source found in /etc/apt/sources.list (or /etc/apt/sources.list.d/*; the files are searched in lexicographic order, and the sources are searched in order inside each file). So list local mirrors first. The order in sources.list is irrelevant for packages that have a different version number.

apt – Rollback All apt-get Packages to Maximum Available Under sources.list

You don't tell how you tried pinning and how it failed, but the solution is pinning indeed. If you've already removed all sources you aren't interested in, create /etc/apt/preferences.d/back.pref with the following contents:

Package: *
Pin: release o=*
Pin-Priority: 1001

After this, apt-get dist-upgrade will up/downgrade all packages to your current sources.

If it doesn't work out, check the output of apt-cache policy and apt-cache policy OFFENDING-PACKAGE for hints.

Best Answer

Related Solutions

APT – How Does apt-get Deal with Multiple Sources

apt – Rollback All apt-get Packages to Maximum Available Under sources.list

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