On 01/02/16 22:47, Didier Kryn wrote:
> Le 01/02/2016 12:09, Florian Zieboll a écrit :
>> florian@nulldevice:~$ cat /etc/apt/apt.conf.d/01norecommend
>> APT::Install-Recommends "0";
>> APT::Install-Suggests "0";
>> #APT::AutoRemove::RecommendsImportant "0";
>>
>> Synaptic will override this setting, if the relevant option is checked.
>
> Apparently synaptic keeps its config in its own config file
> /etc/apt/apt.conf.d/99synaptic. Do you mean synaptic reads all config files in
> order, and since 99synaptic is the last, it can override all previous settings?
> I must confess I don't understand how this set of config files is processed;
> there are quite a lot of files in etc/apt/apt.conf.d/. There's a man for
> apt.conf, which doesn't exist and no man for apt.conf.d, which exists!


the command tool for finding relevant man pages on your system is apropos ...

$ apropos apt

<snip>

apt (1)              - annotation processing tool
apt (8)              - Advanced Package Tool
apt-cache (8)        - query the APT cache
apt-cdrom (8)        - APT CD-ROM management utility
apt-config (8)       - APT Configuration Query program
apt-extracttemplates (1) - Utility to extract debconf config and tem...
apt-file (1)         - APT package searching utility - command-line ...
apt-forktracer (8)   - a utility for managing package versions
apt-ftparchive (1)   - Utility to generate index files
apt-get (8)          - APT package handling utility - - command-line...
apt-key (8)          - APT key management utility
apt-listbugs (1)     - Lists critical bugs before each apt upgrade/i...
apt-mark (8)         - mark/unmark a package as being automatically-...
apt-move (8)         - move cache of Debian packages into a mirror h...
apt-offline (8)      - Offline APT Package manager
apt-secure (8)       - Archive authentication support for APT
apt-show-versions (1p) - Lists available package versions with distr...
apt-sortpkgs (1)     - Utility to sort package index files
apt-zip (8)          - Use apt with removable media
apt-zip-inst (8)     - Use apt with removable media
apt-zip-list (8)     - Use apt with removable media
apt.conf (5)         - Configuration file for APT
apt_preferences (5)  - Preference control file for APT

<snip>

so looking at apt.conf I see as the very first text 'DESCRIPTION'

/etc/apt/apt.conf is the main configuration file shared by all
        the tools in the APT suite of tools, though it is by no means
        the only place options can be set. The suite also shares a
        common command line parser to provide a uniform environment.

        When an APT tool starts up it will read the configuration
        files in the following order:

         1. the file specified by the APT_CONFIG environment variable
            (if any)

         2. all files in Dir::Etc::Parts in alphanumeric ascending
            order which have either no or "conf" as filename extension
            and which only contain alphanumeric, hyphen (-),
            underscore (_) and period (.) characters. Otherwise APT
            will print a notice that it has ignored a file, unless
            that file matches a pattern in the
            Dir::Ignore-Files-Silently configuration list - in which
            case it will be silently ignored.

         3. the main configuration file specified by Dir::Etc::main

         4. the command line options are applied to override the
            configuration directives or to load even more
            configuration files.

Dir::Etc::Parts is in fact apt.conf.d/

as seen by going to the FILES section at the end of the manpage, either with a
search for Dir::Etc::Parts or because you know a FILES section usually exists:

FILES
        /etc/apt/apt.conf
            APT configuration file. Configuration Item:
            Dir::Etc::Main.

        /etc/apt/apt.conf.d/
            APT configuration file fragments. Configuration Item:
            Dir::Etc::Parts.

so certainly finding this out does require a little familiarity with the linux
documentation system, but it is all there and in exactly the discoverable
places. There is a lot of information available, tool tips or a few help
paragraphs could not come close to providing it. That is why very simplified GUI
configurations eliminating all the uncommon settings are so popular.

Simon