On ubuntu, in the /etc/apt/, there are two files: sources.list and sources.list.distUpgrade. But I only know they are used to update system. However, what are the the difference between them? by the way, what the GPG keys used for? when I update the sources.list using ubuntu source list generator, should I update GPG keys as well?

Thanks !


2 Answers 2


When you upgrade between distro versions, .list files in /etc/apt/sources.list.d get commented out. The original versions of those files get backed up with the .distUpgrade extension, and that's what you're seeing. Other than sitting there and being backups, I don't think the .distUpgrade files do anything.

I guess Ubuntu (Debian?) does this out of the presumption that .list files will be incompatible across distro versions, but as a packager, this is pretty inconvenient. Packages like google-chrome install a special cronjob just to work around this issue and un-comment-out their .list file after a dist upgrade.

  • Is there a command that "upgrades" the commented out .distUpgrade files, or is it expected that the users to manually re-enable them by removing .distUpgrade from the file names (and change the content if applicable)? Commented Jun 2 at 9:08

type man apt-get in terminal

       upgrade is used to install the newest versions of all packages
       currently installed on the system from the sources enumerated in
       /etc/apt/sources.list. Packages currently installed with new
       versions available are retrieved and upgraded; under no
       circumstances are currently installed packages removed, or packages
       not already installed retrieved and installed. New versions of
       currently installed packages that cannot be upgraded without
       changing the install status of another package will be left at
       their current version. An update must be performed first so that
       apt-get knows that new versions of packages are available.

       dist-upgrade in addition to performing the function of upgrade,
       also intelligently handles changing dependencies with new versions
       of packages; apt-get has a "smart" conflict resolution system, and
       it will attempt to upgrade the most important packages at the
       expense of less important ones if necessary. The dist-upgrade
       command may therefore remove some packages. The
       /etc/apt/sources.list file contains a list of locations from which
       to retrieve desired package files. See also apt_preferences(5) for
       a mechanism for overriding the general settings for individual
  • 1
    If I want to replace the sources.list for a new one, should I change the GPG keys at the same time?
    – tqjustc
    Commented Apr 28, 2014 at 18:06
  • No. just update .it will automatically update GPG key
    – sohel4r
    Commented Apr 28, 2014 at 18:08
  • First backup sources.list for safety . for more about you can read man sources.list
    – sohel4r
    Commented Apr 28, 2014 at 18:09
  • 8
    This does not answer the question. The OP wants to know the difference between the files, not between apt-get upgrade/dist-upgrade
    – marcv
    Commented May 10, 2016 at 12:21

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