Debian

Debian Policy Manual

The Debian Policy Manual describes the policy requirements for the Debian distribution, including

Contents of the Debian archive
Design issues of the operating system
Technical requirements each package must satisfy to be included in the distribution

Debian Archive

The Debian Archive contains the packages which constitute the Debian system (but see the main area below)

The Debian Archive is described in Section 2 of the Debian Policy Manual.

Areas

Packages of the Debian Archive are located in different areas such as

main
contrib
non-free
non-free-firmware (?)

Main area

The main area consitutes a Debian distribution (as opposed to the Debian system, see above).

No package in the main area is dependent on any software that is not also found in the main area.

Contrib area

The contrib area contains supplemental packages that are dependent on software outside of the distribution to either build or execute.

Packages

Package name

Packages are identified by their names (which must therfore be unique in the Debian Archive).

This name is also found as part of the .deb file's name.

Package sections

Packages in the main, contrib and non-free areas are grouped into sections

The area and section name of a package is stored in the Section control record. If the area is main, this value is omitted. Thus, possible values are

xyz (section xyz in main)
contrib/abc (section abc in contrib)

Some sections (for main?) include

`admin`
`cli-mono`
`comm`
`database`
`debian-installer`	Special packages used by the installer, not used for normal Debian packages
`debug`
`devel`
`doc`
`editors`
`education`
`electronics`
`embedded`
`fonts`
`games`
`gnome`
`gnu-r`
`gnustep`
`graphics`
`hamradio`
`haskell`
`httpd`
`interpreters`
`introspection`
`java`
`javascript`
`kde`
`kernel`
`libdevel`
`libs`
`lisp`
`localization`
`mail`
`math`
`metapackages`
`misc`
`net`
`news`
`ocaml`
`oldlibs`
`otherosfs`
`perl`
`php`
`python`
`ruby`
`rust`
`science`
`shells`
`sound`
`tasks`
`tex`
`text`
`utils`
`vcs`
`video`
`web`
`x11`
`xfce`
`zope`

Package priority

Each package is associated with a priority level.

This value is set in the metadata for the Debian archive and is included in the package's control file.

The list of recognized priority levels is

`required`	Necessary for the proper functioning of the system (usually, this means that `dpkg` depends on these packages). Systems with only the required packages installed have at least enough functionality for the sysadmin to boot the system and install more software. Packages with this level include `base-files`, `base-passwd`, `bash`, `libc-bin`, `passwd`, `debianutils`, `mount` etc.
`important`	Programs which one would expect to find on any Unix-like system (for example `adduser`, `debconf`, `nano` `vim-tiny`, `apt` and `apt-utils`)
`standard`	These packages provide a reasonably small but not too limited character-mode system. This is what will be installed by default if the user doesn’t select anything else. Packages with this level include `bc`, `perl`, `wget`, `dbus`, `media-types` etc.
`optional`	The vast rest of packages (if not `extra`).
`extra`	Deprecated in favor of `optional`.

The union of the packages with level required and important form the base system.

Two packages that both have a priority of standard or higher must not conflict with each other.

Packages with a priority of optional may conflict with each other.

dpkg-query in combination with grep allows to search for packages with a given priority:

$ dpkg-query -W -f='${Package} ${Priority}\n' | grep important | cut -f 1 -d' '

Package format

All packages must be provided in .deb format so that they can be installed and managed with dpkg.

TODO

Interesting packages

Some interesting packages, imho, include:

`base-files`	Contains the basic filesystem hierarchy of a Debian system and files like `/etc/debian_version`, `/etc/dpkg/origins/debian`, `/etc/host.conf`, `/etc/issue`, `/etc/issue.net`, `/etc/os-release`, `/etc/update-motd.d/10-uname`, `/usr/lib/os-release`
`base-passwd`	Template files for `/etc/passwd` and `/etc/group` (stored in `/usr/share/base-passwd`) and the `update-passwd` utility which makes sure that UIDs and GIDs in the 0-99 range are consistent with the Debian master copies.
`build-essential`	which is dependent on `libc6-dev` (`libc-dev`?), `gcc`, `g++`, `make` and `dpkg-dev`
`ca-certificates`	`/usr/sbin/update-ca-certificates`, `/usr/share/ca-certificates/`, `/usr/share/doc/ca-certificates/` …
`certbot`	Configuration of HTTPS using Let's Encrypt.
`console-setup`	Executables such as `setupcon` and `ckbcomp`
`coreutils`	Essential shell commands: `cat`, `cp`, `mv`, `rm`, `touch`, `tail`, `wc` and many more. Compare with the package `9plan`
`debconf`	Configuration management system for Debian packages.
`debianutils`	Commands such as `run-parts`, `installkernel`, `which`, `add-shell`
`debian-keyring`	Keyrings of GnuPG, and keys of Debian developers and maintainers, installed in `/usr/share/keyrings/debian-*`. The authorative source for keyring information is available with `rsync` at `keyring.debian.org::keyrings/keyrings/` and a public view in this git reposiotry. See also `debian-archive-keyring`
`dpkg`	Low-level tools to add and remove Debian packages.
`diffutils`	`diff`, `cmp`, `diff3`, `sdiff`
`init-system-helpers`	Tools that are necessary for switching between the init systems that Debian contains (e. g. sysvinit or systemd).
`keyboard-configuration`	Keyboard preferences in `/etc/default/keyboard`.
`libc6`	Files such as `/etc/ld.so.conf.d/x86_64-linux-gnu.conf`, `/lib/x86_64-linux-gnu/lib*.so`
`libc-bin`	Utility programs and files related to the GNU C Library, for example: `/etc/ld.so.conf.d/libc.conf`, `/sbin/ldconfig`, `/lib64/ld-linux-x86-64.so.2`, `ldd`, `getent` etc.
`linux-headers-$(uname -r)`	`/usr/src/linux-headers-$(uname -r)`
`linux-image-$(uname -r)`	Files such as `System.map.$(uname -r)`, `/boot/config-$(uname r)`, `/boot/vmlinuz-$(uname -r)`; files located under `/lib/modules/$(uname -r)` (`*.ko` files, `modules.builtin`, `modules.buildin.modinfo` and `modules.order`)
`login`	`/bin/login` (the program that invokes a user shell on a virtual terminal), `nologin`, `su`; `/etc/login.defs`
`mesa-utils`	`glxinfo`, `glxheads`, `glxgears`, `glxdemo`
`pkg-config`	Managing compile and link flags (see also the `pkg-config` binary).
`procps`	Utilities related to the proc filesystem (`/proc`): `free`, `kill`, `pgrep`, `pidwait`, `pkill`, `pmap`, `ps`, `pwdx`, `skill`, `slabtop`, `snice`, `tload`, `top`, `uptime`, `vmstat`, `w`, `watch`, `sysctl`. Compare with package psmisc.
`psmisc`	Utilities related to the proc filesystem (`/proc`): `fuser`, `killall`, `peekfd`, `pslog`, `pstree`, `pstree.x11`. Compare wth package procps.
`software-properties-common`	`add-apt-repository` and `apt-add-repository`
`sysstat`	System performance tools: `sar`, `iostat`, `mpstat`, `pidstat`, `sadf` etc.
`util-linux`	See here
`xdg-user-dirs`	Management of well known directories found in the home directory.
`xserver-xorg-core`	XOrg X server. See also the package `libx11-dev` (which comes with files such as `/usr/include/X11/Xlib.h`), `libxt-dev` (which includes `/usr/include/X11/Intrinsic.h`) and `libxaw7-dev` (`/usr/include/X11/Xaw/*`)

Determining version

$ Linux/shell/commands/lsb_release -d
No LSB modules are available
Description:	Debian GNU/Linux 12 (bookworm)