This is documented behavior due to in which order the various configuration places are evaluated: man apt.conf has the details at the top.
In other words, you have to set Dir::Ignore-Files-Silently in a config file specified with the APT_CONFIG environment variable for it to take effect for configuration files. ** Changed in: apt (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to apt in Ubuntu. https://bugs.launchpad.net/bugs/1936273 Title: apt not respecting Ignore-Files-Silently directive Status in apt package in Ubuntu: Invalid Bug description: I have a configuration management system that stores a backup copy of files that it updates with a suffix based upon the date that the file is updated (.YYYY-MM-DD) In Ubuntu 20.04, I have added a file 00ignore to the /etc/apt/apt.conf directory. The contents of the file are one line: Dir::Ignore-Files-Silently:: "\.[12][0-9][0-9][0-9]-[01][0-9]-[0-3][0-9]$"; The system appears to read the file, but doesn't seem to process it, as apt and related programs still spit out warnings. # apt-config dump |grep Ignore Dir::Ignore-Files-Silently ""; Dir::Ignore-Files-Silently:: "~$"; Dir::Ignore-Files-Silently:: "\.disabled$"; Dir::Ignore-Files-Silently:: "\.bak$"; Dir::Ignore-Files-Silently:: "\.dpkg-[a-z]+$"; Dir::Ignore-Files-Silently:: "\.ucf-[a-z]+$"; Dir::Ignore-Files-Silently:: "\.save$"; Dir::Ignore-Files-Silently:: "\.orig$"; Dir::Ignore-Files-Silently:: "\.distUpgrade$"; Dir::Ignore-Files-Silently:: "\.[12][0-9][0-9][0-9]-[01][0-9]-[0-3][0-9]$"; N: Ignoring file '99unclet-override.2021-06-15' in directory '/etc/apt/apt.conf.d/' as it has an invalid filename extension N: Ignoring file '00unclet.2021-06-18' in directory '/etc/apt/apt.conf.d/' as it has an invalid filename extension Note: aptitude does not display this warning, although many other apt- related programs do (e.g. apt, apt-get, apt-config). To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1936273/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp