If an application is available in multiple repositories added in either /etc/apt/sources.list or /etc/apt/sources.list.d/ or any other way, how does sudo apt install determine which repository to use?
Is there some searching order between the added repositories?
Thanks.
If multiple repositories provide the same version of a given package, the first one listed wins:
The files list one source per line (one-line style) or contain multiline stanzas defining one or more sources per stanza (deb822 style), with the most preferred source listed first (in case a single version is available from more than one source).
This also applies across files. /etc/apt/sources.list takes priority over any file in /etc/apt/sources.list.d; the latter are processed in lexical sort order.
There are also apt preferences to "pin" files from a specific server to a higher priority...
ivan@darkstar:/etc/apt$ cat preferences.d/official-package-repositories.pref
Package: *
Pin: origin live.linuxmint.com
Pin-Priority: 750
apt preferences only affect the version of a package which is chosen. If the same version is available from multiple repos, the order determines which repo is used, not the pin priorities. See man apt_preferences for details.
– Stephen Kitt
Oct 28 '18 at 17:26
apt.conf.5 barely mentions them.
– Martian2020
Oct 14 '23 at 15:23
sources.list.dare processed in lexical order, and thatsources.listtakes priority over all of those? The source.list man-page seems to be silent on this. – NickBroon Jun 25 '21 at 11:04ReadMainList()in the APT source code; it reads the mainsources.listfile first, then any files insources.list.d, sorted in lexical order (thetrueflag in the call toGetListOfFilesInDir()requests a sorted list). – Stephen Kitt Jun 28 '21 at 07:45