The Debian GNU/Linux FAQ
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Version 11.0
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Copyright © 1996-2021 Software in the Public Interest
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instead of in the original English.
January 2021
Abstract
This document answers questions frequently asked about Debian GNU/
Linux.
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Table of Contents
1. Definitions and overview
1.1. What is this FAQ?
1.2. What is Debian GNU/Linux?
1.3. OK, now I know what Debian is... what is Linux?!
1.4. Does Debian just do GNU/Linux?
1.5. What is the difference between Debian GNU/Linux and other
Linux distributions? Why should I choose Debian over some other
distribution?
1.6. How does the Debian project fit in or compare with the Free
Software Foundation's GNU project?
1.7. How does one pronounce Debian and what does this word mean?
2. Getting and installing Debian GNU/Linux
2.1. What is the latest version of Debian?
2.2. Are there package upgrades in `stable'?
2.3. Where/how can I get the Debian installation images?
2.4. How do I install Debian from CD-ROMs?
2.5. Why does the official stable released CD-ROM contain
symlinks for `frozen' and `unstable'? I thought this CD contains
just `stable'!
2.6. Can I get and install Debian directly from a remote Internet
site?
2.7. Are there any alternative strategies for booting the system
installer?
3. Choosing a Debian distribution
3.1. Which Debian distribution (stable/testing/unstable) is
better for me?
3.1.1. You asked me to install stable, but in stable so and
so hardware is not detected/working. What should I do?
3.1.2. Will there be different versions of packages in
different distributions?
3.1.3. The stable distributions really contains outdated
packages. Just look at Kde, Gnome, Xorg or even the kernel.
They are very old. Why is it so?
3.1.4. If I were to decide to change to another distribution,
can I do that?
3.1.5. Could you tell me whether to install stable, testing
or unstable?
3.1.6. You are talking about testing being broken. What do
you mean by that?
3.1.7. Why is it that testing could be broken for months?
Won't the fixes introduced in unstable flow directly down
into testing?
3.1.8. From an administrator's point of view, which
distribution requires more attention?
3.1.9. What happens when a new release is made?
3.1.10. I have a working Desktop/cluster with Debian
installed. How do I know which distribution I am running?
3.1.11. I am currently tracking stable. Can I change to
testing or unstable? If so, how?
3.1.12. I am currently tracking testing (bookworm). What will
happen when a release is made? Will I still be tracking
testing or will my machine be running the new stable
distribution?
3.1.13. I am still confused. What did you say I should
install?
3.2. But what about Knoppix, Linux Mint Debian Edition, Ubuntu,
and others?
3.2.1. I know that Knoppix/Linux Mint Debian Edition/Ubuntu
/... is Debian-based. So after installing it on the hard
disk, can I use 'apt' package tools on it?
3.2.2. I installed Knoppix/Linux Mint Debian Edition/Ubuntu
/... on my hard disk. Now I have a problem. What should I do?
3.2.3. I'm using Knoppix/LMDE/Ubuntu/... and now I want to
use Debian. How do I migrate?
4. Compatibility issues
4.1. On what hardware architectures/systems does Debian GNU/Linux
run?
4.2. What kernels does Debian GNU/Linux run?
4.3. How compatible is Debian with other distributions of Linux?
4.4. How source code compatible is Debian with other Unix
systems?
4.5. Can I use Debian packages (".deb" files) on my Red Hat/
Slackware/... Linux system? Can I use Red Hat packages (".rpm"
files) on my Debian GNU/Linux system?
4.6. How should I install a non-Debian program?
5. Software available in the Debian system
5.1. What types of applications and development software are
available for Debian GNU/Linux?
5.2. Who wrote all that software?
5.3. How can I get a current list of programs that have been
packaged for Debian?
5.4. How can I install a developer's environment to build
packages?
5.5. What is missing from Debian GNU/Linux?
5.6. Why do I get "ld: cannot find -lfoo" messages when compiling
programs? Why aren't there any libfoo.so files in Debian library
packages?
5.7. (How) Does Debian support Java?
5.8. How can I check that I am using a Debian system, and what
version it is?
5.9. How does Debian support non-English languages?
5.10. Where is ezmlm/djbdns/qmail?
5.11. Where is a player for Flash (SWF)?
5.12. Where is Google Earth?
5.13. Where is VoIP software?
5.14. I have a wireless network card which doesn't work with
Linux. What should I do?
6. The Debian archives
6.1. How many Debian distributions are there?
6.2. What are all those names like etch, lenny, etc.?
6.2.1. Which other codenames have been used in the past?
6.2.2. Where do these codenames come from?
6.3. What about "sid"?
6.4. What does the stable directory contain?
6.5. What does the testing distribution contain?
6.5.1. What about "testing"? How is it `frozen'?
6.6. What does the unstable distribution contain?
6.7. What are all those directories at the Debian archives?
6.8. What are all those directories inside dists/stable/main?
6.9. Where is the source code?
6.10. What's in the pool directory?
6.11. What is "incoming"?
6.12. How do I set up my own apt-able repository?
7. Basics of the Debian package management system
7.1. What is a Debian package?
7.2. What is the format of a Debian binary package?
7.3. Why are Debian package file names so long?
7.4. What is a Debian control file?
7.5. What is a Debian conffile?
7.6. What is a Debian preinst, postinst, prerm, and postrm
script?
7.7. What is an Essential, Required, Important, Standard,
Optional, or Extra package?
7.8. What is a Virtual Package?
7.9. What is meant by saying that a package Depends, Recommends,
Suggests, Conflicts, Replaces, Breaks or Provides another
package?
7.10. What is meant by Pre-Depends?
7.11. What is meant by unknown, install, remove, purge and hold
in the package status?
7.12. How do I put a package on hold?
7.13. How do I install a source package?
7.14. How do I build binary packages from a source package?
7.15. How do I create Debian packages myself?
8. The Debian package management tools
8.1. What programs does Debian provide for managing its packages?
8.1.1. dpkg
8.1.2. APT
8.1.3. aptitude
8.1.4. synaptic
8.1.5. tasksel
8.1.6. Other package management tools
8.2. Debian claims to be able to update a running program; how is
this accomplished?
8.3. How can I tell what packages are already installed on a
Debian system?
8.4. How do I display the files of an installed package?
8.5. How can I find out what package produced a particular file?
8.6. Why is `foo-data' not removed when I uninstall `foo'? How do
I make sure old unused library-packages get purged?
9. Keeping your Debian system up-to-date
9.1. How can I keep my Debian system current?
9.1.1. aptitude
9.1.2. apt-get and apt-cdrom
9.2. Must I go into single user mode in order to upgrade a
package?
9.3. Do I have to keep all those .deb archive files on my disk?
9.4. How can I keep a log of the packages I added to the system?
I'd like to know when upgrades and removals have occurred and on
which packages!
9.5. Can I automatically update the system?
9.6. I have several machines; how can I download the updates only
one time?
10. Debian and the kernel
10.1. Can I install and compile a kernel without some
Debian-specific tweaking?
10.2. What tools does Debian provide to build custom kernels?
10.3. What special provisions does Debian provide to deal with
modules?
10.4. Can I safely de-install an old kernel package, and if so,
how?
10.5. Where can I get more information about Linux packages for
Debian?
11. Customizing your Debian GNU/Linux system
11.1. How can I ensure that all programs use the same paper size?
11.2. How can I provide access to hardware peripherals, without
compromising security?
11.3. How do I load a console font on startup the Debian way?
11.4. How can I configure an X11 program's application defaults?
11.5. How does a Debian system boot?
11.6. And how about Debian and traditional System V init?
11.7. And are there yet other ways of booting a Debian system?
11.8. How does the package management system deal with packages
that contain configuration files for other packages?
11.9. How do I override a file installed by a package, so that a
different version can be used instead?
11.10. How can I have my locally-built package included in the
list of available packages that the package management system
knows about?
11.11. Some users like mawk, others like gawk; some like vim,
others like elvis; some like trn, others like tin; how does
Debian support diversity?
12. Getting support for Debian GNU/Linux
12.1. What other documentation exists on and for a Debian system?
12.2. Are there any on-line resources for discussing Debian?
12.2.1. Mailing lists
12.2.2. Web forum
12.2.3. Wiki
12.2.4. Maintainers
12.2.5. Usenet newsgroups
12.3. Is there a quick way to search for information on Debian
GNU/Linux?
12.4. Are there logs of known bugs?
12.5. How do I report a bug in Debian?
13. Contributing to the Debian Project
13.1. How can I become a Debian member/Debian developer?
13.2. How can I contribute resources to the Debian project?
13.3. How can I contribute financially to the Debian project?
13.3.1. Software in the Public Interest
13.3.2. Other organizations
14. Redistributing Debian GNU/Linux in a commercial product
14.1. Can I make and sell Debian CDs?
14.2. Can Debian be packaged with non-free software?
14.3. I am making a special Linux distribution for a "vertical
market". Can I use Debian GNU/Linux for the guts of a Linux
system and add my own applications on top of it?
14.4. Can I put my commercial program in a Debian "package" so
that it installs effortlessly on any Debian system?
15. Changes expected in the next major release of Debian
15.1. Hardening the system
15.2. Extended support for non-English users
15.3. Improvements in the Debian Installer
15.4. More architectures
15.5. More kernels
16. General information about the FAQ
16.1. Authors
16.2. Feedback
16.3. Availability
16.4. Document format
Chapter 1. Definitions and overview
1.1. What is this FAQ?
This document gives frequently asked questions (with their
answers!) about the Debian distribution (Debian GNU/Linux and
others) and about the Debian project. If applicable, pointers to
other documentation will be given: we won't quote large parts of
external documentation in this document. You'll find out that
some answers assume some knowledge of Unix-like operating
systems. We'll try to assume as little prior knowledge as
possible: answers to general beginners questions will be kept
simple.
If you can't find what you're looking for in this FAQ, be sure to
check out Section 12.1, “What other documentation exists on and
for a Debian system?”. If even that doesn't help, refer to
Section 16.2, “Feedback”.
1.2. What is Debian GNU/Linux?
Debian GNU/Linux is a particular distribution of the Linux
operating system, and numerous packages that run on it.
Debian GNU/Linux is:
* full featured: Debian includes more than 59100 software
packages at present. Users can select which packages to
install; Debian provides a tool for this purpose. You can
find a list and descriptions of the packages currently
available in Debian at any of the Debian mirror sites (https:
//www.debian.org/distrib/ftplist) .
* free to use and redistribute: There is no consortium
membership or payment required to participate in its
distribution and development. All packages that are formally
part of Debian GNU/Linux are free to redistribute, usually
under terms specified by the GNU General Public License.
The Debian archives also carry approximately 1000 software
packages (in the non-free and contrib sections), which are
distributable under specific terms included with each
package.
* dynamic: With about 1012 volunteers constantly contributing
new and improved code, Debian is evolving rapidly. The
archives are updated twice every day.
Most Linux users run a specific distribution of Linux, like
Debian GNU/Linux. However, in principle, users could obtain the
Linux kernel via the Internet or from elsewhere, and compile it
themselves. They could then obtain source code for many
applications in the same way, compile the programs, then install
them into their systems. For complicated programs, this process
can be not only time-consuming but error-prone. To avoid it,
users often choose to obtain the operating system and the
application packages from one of the Linux distributors. What
distinguishes the various Linux distributors are the software,
protocols, and practices they use for packaging, installing, and
tracking applications packages on users' systems, combined with
installation and maintenance tools, documentation, and other
services.
Debian GNU/Linux is the result of a volunteer effort to create a
free, high-quality Unix-compatible operating system, complete
with a suite of applications. The idea of a free Unix-like system
originates from the GNU project, and many of the applications
that make Debian GNU/Linux so useful were developed by the GNU
project.
For Debian, free has the GNUish meaning (see the Debian Free
Software Guidelines (https://www.debian.org/social_contract#
guidelines) ). When we speak of free software, we are referring
to freedom, not price. Free software means that you have the
freedom to distribute copies of free software, that you receive
source code or can get it if you want it, that you can change the
software or use pieces of it in new free programs; and that you
know you can do these things.
The Debian Project was created by Ian Murdock in 1993, initially
under the sponsorship of the Free Software Foundation's GNU
project. Today, Debian's developers think of it as a direct
descendent of the GNU project.
Although Debian GNU/Linux itself is free software, it is a base
upon which value-added Linux distributions can be built. By
providing a reliable, full-featured base system, Debian provides
Linux users with increased compatibility, and allows Linux
distribution creators to eliminate duplication of effort and
focus on the things that make their distribution special. See
Section 14.3, “I am making a special Linux distribution for a
"vertical market". Can I use Debian GNU/Linux for the guts of a
Linux system and add my own applications on top of it?” for more
information.
1.3. OK, now I know what Debian is... what is Linux?!
In short, Linux is the kernel of a Unix-like operating system. It
was originally designed for 386 (and better) PCs; today Linux
also runs on a dozen of other systems. Linux is written by Linus
Torvalds and many computer scientists around the world.
Besides its kernel, a "Linux" system usually has:
* a file system that follows the Linux Filesystem Hierarchy
Standard https://www.pathname.com/fhs (https://
www.pathname.com/fhs) .
* a wide range of Unix utilities, many of which have been
developed by the GNU project and the Free Software
Foundation.
The combination of the Linux kernel, the file system, the GNU and
FSF utilities, and the other utilities are designed to achieve
compliance with the POSIX (IEEE 1003.1) standard; see
Section 4.4, “How source code compatible is Debian with other
Unix systems?”.
For more information about Linux, see What is Linux (https://
www.linux.org/info/) by Linux Online (https://www.linux.org/) .
1.4. Does Debian just do GNU/Linux?
Currently, Debian is only available for Linux, but with Debian
GNU/Hurd and Debian on BSD kernels, we have started to offer
non-Linux-based OSes as a development, server and desktop
platform, too. However, these non-linux ports are not officially
released yet.
The oldest porting effort is Debian GNU/Hurd.
The Hurd is a set of servers running on top of the GNU Mach
microkernel. Together they build the base for the GNU operating
system.
Please see https://www.gnu.org/software/hurd (https://www.gnu.org
/software/hurd) for more information about the GNU/Hurd in
general, and https://www.debian.org/ports/hurd/ (https://
www.debian.org/ports/hurd/) for more information about Debian GNU
/Hurd.
A second effort is the port to a BSD kernel. People are working
with the FreeBSD kernel.
See https://www.debian.org/ports/#nonlinux (https://
www.debian.org/ports/#nonlinux) for more information about these
non-linux ports.
1.5. What is the difference between Debian GNU/Linux and other Linux
distributions? Why should I choose Debian over some other
distribution?
These key features distinguish Debian from other Linux
distributions:
Freedom:
As stated in the Debian Social Contract (https://
www.debian.org/social_contract) , Debian will remain 100%
free. Debian is very strict about shipping truly free
software. The guidelines used to determine if a work is
"free" are provided in The Debian Free Software Guidelines
(DFSG) (https://www.debian.org/social_contract#guidelines) .
The Debian package maintenance system:
The entire system, or any individual component of it, can be
upgraded in place without reformatting, without losing custom
configuration files, and (in most cases) without rebooting
the system. Most Linux distributions available today have
some kind of package maintenance system; the Debian package
maintenance system is unique and particularly robust (see
Chapter 7, Basics of the Debian package management system).
Open development:
Whereas many other Linux distributions are developed by
individuals, small, closed groups, or commercial vendors,
Debian is a major Linux distribution that is being developed
by an association of individuals who have made common cause
to create a free operating system, in the same spirit as
Linux and other free software.
More than 1012 volunteer package maintainers are working on
over 59100 packages and improving Debian GNU/Linux. The
Debian developers contribute to the project not by writing
new applications (in most cases), but by packaging existing
software according to the standards of the project, by
communicating bug reports to upstream developers, and by
providing user support. See also additional information on
how to become a contributor in Chapter 13, Contributing to
the Debian Project.
The Universal Operating System:
Debian comes with more than 59100 packages (https://
packages.debian.org/stable/) and runs on 9 architectures
(https://www.debian.org/ports/) . This is far more than is
available for any other GNU/Linux distribution. See
Section 5.1, “What types of applications and development
software are available for Debian GNU/Linux?” for an overview
of the provided software and see Section 4.1, “On what
hardware architectures/systems does Debian GNU/Linux run?”
for a description of the supported hardware platforms.
The Bug Tracking System:
The geographical dispersion of the Debian developers required
sophisticated tools and quick communication of bugs and
bug-fixes to accelerate the development of the system. Users
are encouraged to send bugs in a formal style, which are
quickly accessible by WWW archives or via e-mail. See
additional information in this FAQ on the management of the
bug log in Section 12.4, “Are there logs of known bugs?”.
The Debian Policy:
Debian has an extensive specification of our standards of
quality, the Debian Policy. This document defines the
qualities and standards to which we hold Debian packages.
For additional information about this, please see our web page
about reasons to choose Debian (https://www.debian.org/intro/
why_debian) .
1.6. How does the Debian project fit in or compare with the Free
Software Foundation's GNU project?
The Debian system builds on the ideals of free software first
championed by the Free Software Foundation (https://www.gnu.org/)
and in particular by Richard Stallman (https://www.stallman.org/)
. FSF's powerful system development tools, utilities, and
applications are also a key part of the Debian system.
The Debian Project is a separate entity from the FSF, however we
communicate regularly and cooperate on various projects. The FSF
explicitly requested that we call our system "Debian GNU/Linux",
and we are happy to comply with that request.
The FSF's long-standing objective is to develop a new operating
system called GNU, based on Hurd (https://www.gnu.org/software/
hurd) . Debian is working with FSF on this system, called Debian
GNU/Hurd (https://www.debian.org/ports/hurd/) .
1.7. How does one pronounce Debian and what does this word mean?
The project name is pronounced Deb'-ee-en, with a short e in Deb,
and emphasis on the first syllable. This word is a contraction of
the names of Debra and Ian Murdock, who founded the project.
(Dictionaries seem to offer some ambiguity in the pronunciation
of Ian (!), but Ian prefers ee'-en.)
Chapter 2. Getting and installing Debian GNU/Linux
The official document giving installation instructions is the
Debian GNU/Linux Installation Guide (https://www.debian.org/
releases/stable/installmanual) . We'll give some additional notes
about getting and installing Debian GNU/Linux here.
2.1. What is the latest version of Debian?
Currently there are three versions of Debian GNU/Linux:
release 11, a.k.a. the `stable' distribution or bullseye
This is stable and well tested software, it changes if major
security or usability fixes are incorporated.
the `testing' distribution, currently called bookworm
This is where packages that will be released as the next
`stable' are placed; they've had some testing in unstable but
they may not be completely fit for release yet. This
distribution is updated more often than `stable', but not
more often than `unstable'.
the `unstable' distribution
This is the version currently under development; it is
updated continuously. You can retrieve packages from the
`unstable' archive on any Debian mirror site and use them to
upgrade your system at any time, but you may not expect the
system to be as usable or as stable as before - that's why
it's called `unstable'!
Please see Section 6.1, “How many Debian distributions are there?
” for more information.
2.2. Are there package upgrades in `stable'?
No new functionality is added to the stable release. Once a
Debian version is released and tagged `stable' it will only get
security updates. That is, only packages for which a security
vulnerability has been found after the release will be upgraded.
All the security updates are served through security.debian.org
(https://security.debian.org) .
Security updates serve one purpose: to supply a fix for a
security vulnerability. They are not a method for sneaking
additional changes into the stable release without going through
normal point release procedure. Consequently, fixes for packages
with security issues will not upgrade the software. The Debian
Security Team will backport the necessary fixes to the version of
the software distributed in `stable' instead.
For more information related to security support please read the
Security FAQ (https://www.debian.org/security/faq) or the Debian
Security Manual (https://www.debian.org/doc/manuals/
securing-debian-howto/) .
2.3. Where/how can I get the Debian installation images?
You can get the installation images by downloading the
appropriate files from the Debian website (https://www.debian.org
/distrib/) .
Please refer to Debian GNU/Linux on CDs (https://www.debian.org/
CD) for more information about CD (and DVD) images.
2.4. How do I install Debian from CD-ROMs?
Installing Debian from CD is straightforward: configure your
system for booting off a CD, insert your CD, and reboot. Your
system will now be running the Debian Installer. See the Debian
GNU/Linux Installation Guide (https://www.debian.org/releases/
stable/installmanual) for more information.
2.5. Why does the official stable released CD-ROM contain symlinks
for `frozen' and `unstable'? I thought this CD contains just
`stable'!
Official Debian CD images indeed contain symlinks like:
/dists/frozen -> bullseye/
/dists/stable -> bullseye/
/dists/testing -> bullseye/
/dists/unstable -> bullseye/
so that they work when your sources.list has an entry like
deb cdrom:[<name as on cd label>]/ unstable main [...]
.
The fact these symlinks are present does not mean the image is
`unstable' or `testing' or anything. Read the CD label in /.disk/
info to find out which Debian version it contains. This
information is also present in /README.txt on the CD.
Read https://www.debian.org/releases (https://www.debian.org/
releases) to find out what the current `stable' and `testing'
releases are.
2.6. Can I get and install Debian directly from a remote Internet
site?
Yes. You can boot the Debian installation system from a set of
files you can download from our archive site and its mirrors.
You can download a small CD image file, create a bootable CD from
it, install the basic system from it and the rest over the
network. For more information please see https://www.debian.org/
CD/netinst/ (https://www.debian.org/CD/netinst/) .
2.7. Are there any alternative strategies for booting the system
installer?
Yes. Apart from CD or DVD, you can install Debian GNU/Linux by
booting from USB memory stick, directly from hard disk, or using
TFTP net booting. For installing on multiple computers it's
possible to do fully automatic installations. NB: not all methods
are supported by all computer architectures. Once the installer
has booted, the rest of the system can be downloaded over the
network, or installed from local media. See the Debian GNU/Linux
Installation Guide (https://www.debian.org/releases/stable/
installmanual) for more information.
Chapter 3. Choosing a Debian distribution
There are many different Debian distributions. Choosing the
proper Debian distribution is an important decision. This section
covers some information useful for users that want to make the
choice best suited for their system and also answers possible
questions that might be arising during the process. It does not
deal with "why you should choose Debian" but rather "which
distribution of Debian".
For more information on the available distributions read
Section 6.1, “How many Debian distributions are there?”.
3.1. Which Debian distribution (stable/testing/unstable) is better
for me?
The answer is a bit complicated. It really depends on what you
intend to do. One solution would be to ask a friend who runs
Debian. But that does not mean that you cannot make an
independent decision. In fact, you should be able to decide once
you complete reading this chapter.
* If security or stability are at all important for you:
install stable. period. This is the most preferred way.
* If you are a new user installing to a desktop machine, start
with stable. Some of the software is quite old, but it's the
least buggy environment to work in. You can easily switch to
the more modern unstable (or testing) once you are a little
more confident.
* If you are a desktop user with a lot of experience in the
operating system and do not mind facing the odd bug now and
then, or even full system breakage, use unstable. It has all
the latest and greatest software, and bugs are usually fixed
swiftly.
* If you are running a server, especially one that has strong
stability requirements or is exposed to the Internet, install
stable. This is by far the strongest and safest choice.
The following questions (hopefully) provide more detail on these
choices. After reading this whole FAQ, if you still could not
make a decision, stick with the stable distribution.
3.1.1. You asked me to install stable, but in stable so and so
hardware is not detected/working. What should I do?
Try to search the web using a search engine and see if someone
else is able to get it working in stable. Most of the hardware
should work fine with stable. But if you have some
state-of-the-art, cutting edge hardware, it might not work with
stable. If this is the case, you might want to install/upgrade to
either testing or unstable.
For laptops, https://www.linux-on-laptops.com/ (https://
www.linux-on-laptops.com/) is a very good website to see if
someone else is able to get it to work under Linux. The website
is not specific to Debian, but is nevertheless a tremendous
resource. I am not aware of any such website for desktops.
Another option would be to ask in the debian-user mailing list by
sending an email to debian-user@lists.debian.org. Messages can be
posted to the list even without subscribing. The archives can be
read through https://lists.debian.org/debian-user/ (https://
lists.debian.org/debian-user/) . Information regarding
subscribing to the list can be found at the location of archives.
You are strongly encouraged to post your questions on the
mailing-list rather than on irc (https://www.debian.org/support)
. The mailing-list messages are archived, so the solution to your
problem can help others with the same issue.
3.1.2. Will there be different versions of packages in different
distributions?
Yes. Unstable has the most recent (latest) versions. But the
packages in unstable are not well tested and might have bugs.
On the other hand, stable contains old versions of packages. But
this package is well tested and is less likely to have any bugs.
The packages in testing fall between these two extremes.
3.1.3. The stable distributions really contains outdated packages.
Just look at Kde, Gnome, Xorg or even the kernel. They are very old.
Why is it so?
Well, you might be correct. The age of the packages at stable
depends on when the last release was made. Since there is
typically over 1 year between releases you might find that stable
contains old versions of packages. However, they have been tested
in and out. One can confidently say that the packages do not have
any known severe bugs, security holes etc., in them. The packages
in stable integrate seamlessly with other stable packages. These
characteristics are very important for production servers which
have to work 24 hours a day, 7 days a week.
On the other hand, packages in testing or unstable can have
hidden bugs, security holes etc. Moreover, some packages in
testing and unstable might not be working as intended. Usually
people working on a single desktop prefer having the latest and
most modern set of packages. Unstable is the solution for this
group of people.
As you can see, stability and novelty are two opposing ends of
the spectrum. If stability is required: install stable
distribution. If you want to work with the latest packages, then
install unstable.
3.1.4. If I were to decide to change to another distribution, can I
do that?
Yes, but it is a one way process. You can go from stable -->
testing --> unstable. But the reverse direction is not
"possible". So better be sure if you are planning to install/
upgrade to unstable.
Actually, if you are an expert and if you are willing to spend
some time and if you are real careful and if you know what you
are doing, then it might be possible to go from unstable to
testing and then to stable. The installer scripts are not
designed to do that. So in the process, your configuration files
might be lost and...
3.1.5. Could you tell me whether to install stable, testing or
unstable?
No. This is a rather subjective issue. There is no perfect answer
as it depends on your software needs, your willingness to deal
with possible breakage, and your experience in system
administration. Here are some tips:
* Stable is rock solid. It does not break and has full security
support. But it not might have support for the latest
hardware.
* Testing has more up-to-date software than Stable, and it
breaks less often than Unstable. But when it breaks, it might
take a long time for things to get rectified. Sometimes this
could be days and it could be months at times. It also does
not have permanent security support.
* Unstable has the latest software and changes a lot.
Consequently, it can break at any point. However, fixes get
rectified in many occasions in a couple of days and it always
has the latest releases of software packaged for Debian.
When deciding between testing and unstable bear in mind that
there might be times when tracking testing would be beneficial as
opposed to unstable. One of this document's authors experienced
such situation due to the gcc transition from gcc3 to gcc4. He
was trying to install the labplot package on a machine tracking
unstable and it could not be installed in unstable as some of its
dependencies have undergone gcc4 transition and some have not.
But the package in testing was installable on a testing machine
as the gcc4 transitioned packages had not "trickled down" to
testing.
3.1.6. You are talking about testing being broken. What do you mean
by that?
Sometimes, a package might not be installable through package
management tools. Sometimes, a package might not be available at
all, maybe it was (temporarily) removed due to bugs or unmet
dependencies. Sometimes, a package installs but does not behave
in the proper way.
When these things happen, the distribution is said to be broken
(at least for this package).
3.1.7. Why is it that testing could be broken for months? Won't the
fixes introduced in unstable flow directly down into testing?
The bug fixes and improvements introduced in the unstable
distribution trickle down to testing after a certain number of
days. Let's say this threshold is 5 days. The packages in
unstable go into testing only when there are no RC-bugs reported
against them. If there is a RC-bug filed against a package in
unstable, it will not go into testing after the 5 days.
The idea is that, if the package has any problems, it would be
discovered by people using unstable and will be fixed before it
enters testing. This keeps testing in a usable state for most of
the time. Overall a brilliant concept, if you ask me. But things
aren't always that simple. Consider the following situation:
* Imagine you are interested in package XYZ.
* Let's assume that on June 10, the version in testing is
XYZ-3.6 and in unstable it is XYZ-3.7.
* After 5 days, XYZ-3.7 from unstable migrates into testing.
* So on June 15, both testing and unstable have XYZ-3.7 in
their repositories.
* Let's say, the user of testing distribution sees that a new
XYZ package is available and updates the XYZ-3.6 to XYZ-3.7.
* Now on June 25, someone using testing or unstable discovers
an RC bug in XYZ-3.7 and files it in the BTS.
* The maintainer of XYZ fixes this bug and uploads it to
unstable say on June 30. Here it is assumed that it takes 5
days for the maintainer to fix the bug and upload the new
version. The number 5 should not be taken literally. It could
be less or more, depending upon the severity of the RC-bug at
hand.
* This new version in unstable, XYZ-3.8 is scheduled to enter
testing on July 5th.
* But on July 3rd some other person discovers another RC-bug in
XYZ-3.8.
* Let's say the maintainer of XYZ fixes this new RC-bug and
uploads new version of XYZ after 5 days.
* So on July 8th, testing has XYZ-3.7 while unstable has
XYZ-3.9.
* This new version XYZ-3.9 is now rescheduled to enter testing
on July 13th.
* Now since you are running testing, and since XYZ-3.7 is
buggy, you could probably use XYZ only after July 13th. That
is you essentially ended up with a broken XYZ for about one
month.
The situation can get much more complicated, if say, XYZ depends
on 4 other packages. This could in turn lead to an unusable
testing distribution for months. While the scenario above is
immaginary, similar things can occur in real life, though they
are rare.
3.1.8. From an administrator's point of view, which distribution
requires more attention?
One of the main reasons why many people choose Debian over other
Linux distributions is that it requires very little
administration. People want a system that just works. In general
one can say that stable requires very little maintenance, while
testing and unstable require constant maintenance from the
administrator. If you are running stable, all you need to worry
about is keeping track of security updates. If you are running
either testing or unstable it is a good idea to be aware of the
new bugs discovered in the installed packages, new bugfixes/
features introduced etc.
3.1.9. What happens when a new release is made?
This question will not help you in choosing a Debian
distribution. But sooner or later you will face this question.
The stable distribution is currently bullseye; The next stable
distribution will be called bookworm. Let's consider the
particular case of what happens when bookworm is released as the
new stable version.
* oldstable = buster; stable = bullseye; testing = bookworm;
unstable = sid
* Unstable is always referred to as sid irrespective of whether
a release is made or not.
* Packages constantly migrate from sid to testing (i.e.
bookworm). But packages in stable (i.e. bullseye) remain the
same except for security updates.
* After some time testing becomes frozen. But it will still be
called testing. At this point no new packages from unstable
can migrate to testing unless they include release-critical
(RC) bug fixes.
* When testing is frozen, all the new bugfixes introduced have
to be manually checked by the members of the release team.
This is done to ensure that there won't be any unknown severe
problems in the frozen testing.
* RC bugs in 'frozen testing' are reduced to either zero or, if
greater than zero, the bugs are either marked as ignored for
the release or are deferred for a point release.
* The 'frozen testing' with no rc-bugs will be released as the
new stable version. In our example, this new stable release
will be called bookworm.
* At this stage oldstable = bullseye, stable = bookworm. The
contents of stable and 'frozen testing' are same at this
point.
* A new testing is based on the old testing.
* Packages start coming down from sid to testing and the Debian
community will be working towards making the next stable
release.
3.1.10. I have a working Desktop/cluster with Debian installed. How
do I know which distribution I am running?
In most situations it is very easy to figure this out. Take a
look at the /etc/apt/sources.list file. There will be an entry
similar to this:
deb http://ftp.us.debian.org/debian/ unstable main contrib
The third field ('unstable' in the above example) indicates the
Debian distribution the system is currently tracking.
You can also use lsb_release (available in the lsb-release
package). If you run this program in an unstable system you will
get:
$ lsb_release -a
LSB Version: core-2.0-noarch:core-3.0-noarch:core-3.1-noarch:core-2.0-ia32:core-3.0-ia32:core-3.1-ia32
Distributor ID: Debian
Description: Debian GNU/Linux unstable (sid)
Release: unstable
Codename: sid
However, this is not always that easy. Some systems might have
sources.list files with multiple entries corresponding to
different distributions. This could happen if the administrator
is tracking different packages from different Debian
distributions. This is frequently referred to as apt-pinning.
These systems might run a mixture of distributions.
3.1.11. I am currently tracking stable. Can I change to testing or
unstable? If so, how?
If you are currently running stable, then in the /etc/apt/
sources.list file the third field will be either 'bullseye' or
'stable'. You need to change this to the distribution you want to
run. If you want to run testing, then change the third field of /
etc/apt/sources.list to 'testing'. If you want to run unstable,
then change the third field to 'unstable'.
Currently testing is called bookworm. So, if you change the third
field of /etc/apt/sources.list to 'bookworm', then also you will
be running testing. But even when bookworm becomes stable, you
will still be tracking bookworm.
Unstable is always called Sid. So if you change the third field
of /etc/apt/sources.list to 'sid', then you will be tracking
unstable.
Currently Debian offers security updates for testing but not for
unstable, as fixes in unstable are directly made to the main
archive. So if you are running unstable make sure that you remove
the lines relating to security updates in /etc/apt/sources.list.
If there is a release notes document available for the
distribution you are upgrading to (even though it has not yet
been released) it would be wise to review it, as it might provide
information on how you should upgrade to it.
Nevertheless, once you make the above changes, you can run
aptitude update and then install the packages that you want.
Notice that installing a package from a different distribution
might automatically upgrade half of your system. If you install
individual packages you will end up with a system running mixed
distributions.
It might be best in some situations to just fully upgrade to the
new distribution running apt full-upgrade, aptitude safe-upgrade
or aptitude full-upgrade. Read apt's and aptitude's manual pages
for more information.
3.1.12. I am currently tracking testing (bookworm). What will happen
when a release is made? Will I still be tracking testing or will my
machine be running the new stable distribution?
It depends on the entries in the /etc/apt/sources.list file. If
you are currently tracking testing, these entries are similar to
either:
deb http://ftp.us.debian.org/debian/ testing main
or
deb http://ftp.us.debian.org/debian/ bookworm main
If the third field in /etc/apt/sources.list is 'testing' then you
will be tracking testing even after a release is made. So after
bookworm is released, you will be running a new Debian
distribution which will have a different codename. Changes might
not be apparent at first but will be evident as soon as new
packages from unstable go over to the testing distribution.
But if the third field contains 'bookworm' then you will be
tracking stable (since bookworm will then be the new stable
distribution).
3.1.13. I am still confused. What did you say I should install?
If unsure, the best bet would be the stable distribution.
3.2. But what about Knoppix, Linux Mint Debian Edition, Ubuntu, and
others?
They are not Debian; they are Debian based. Though there are many
similarities and commonalities between them, there are also
crucial differences.
All these distributions have their own merits and are suited to
some specific set of users. For more information, read Software
distributions based on Debian (https://www.debian.org/misc/
children-distros) available at the Debian website.
3.2.1. I know that Knoppix/Linux Mint Debian Edition/Ubuntu/... is
Debian-based. So after installing it on the hard disk, can I use
'apt' package tools on it?
These distributions are Debian based. But they are not Debian.
You will be still able to use apt package tools by pointing the /
etc/apt/sources.list file to these distributions' repositories.
But then you are not running Debian, you are running a different
distribution. They are not the same.
In most situations if you stick with one distribution you should
use that and not mix packages from other distributions. Many
common breakages arise due to people running a distribution and
trying to install Debian packages from other distributions. The
fact that they use the same formatting and name (.deb), does not
make them immediately compatible.
For example, Knoppix is a Linux distribution designed to be
booted as a live CD whereas Debian is designed to be installed on
the hard-disk. Knoppix is great if you want to know whether a
particular piece of hardware works, or if you want to experience
how a GNU/Linux system 'feels' etc., Knoppix is good for
demonstration purposes while Debian is designed to run 24/7.
Moreover the number of packages available, the number of
architectures supported by Debian are far more than that of
Knoppix.
If you want Debian, it is best to install Debian from the get-go.
Although it is possible to install Debian through other
distributions, such as Knoppix, the procedure calls for
expertise. If you are reading this FAQ, I would assume that you
are new to both Debian and Knoppix. In that case, save yourself a
lot of trouble later and install Debian right at the beginning.
3.2.2. I installed Knoppix/Linux Mint Debian Edition/Ubuntu/... on my
hard disk. Now I have a problem. What should I do?
You are advised not to use the Debian forums (either mailing
lists or IRC) for help as people there may base their suggestions
on the assumption that you are running a Debian system. These
"fixes" might not be suited to what you are running, and might
even make your problem worse.
Use the forums of the specific distribution you are using first.
If you do not get help or the help you get does not fix your
problem you might want to try asking in Debian forums, but keep
the advice of the previous paragraph in mind.
3.2.3. I'm using Knoppix/LMDE/Ubuntu/... and now I want to use
Debian. How do I migrate?
Consider the change from a Debian-based distribution to Debian
just like a change from one operating system to another one. You
should make a backup of all your data and reinstall the operating
system from scratch. You should not attempt to "upgrade" to
Debian using the package management tools as you might end up
with an unusable system.
If all your user data (i.e. your /home) is under a separate
partition migrating to Debian is actually quite simple, you just
have to tell the installation system to mount (but not reformat)
that partition when reinstalling. Making backups of your data, as
well as your previous system's configuration (i.e. /etc/ and,
maybe, /var/) is still encouraged.
Chapter 4. Compatibility issues
4.1. On what hardware architectures/systems does Debian GNU/Linux
run?
Debian GNU/Linux includes complete source-code for all of the
included programs, so it should work on all systems which are
supported by the Linux kernel; see the Linux FAQ (http://
en.tldp.org/FAQ/Linux-FAQ/intro.html#
DOES-LINUX-RUN-ON-MY-COMPUTER) for details.
The current Debian GNU/Linux release, 11, contains a complete,
binary distribution for the following architectures:
* amd64: this covers systems based on AMD 64bit CPUs with AMD64
extension and all Intel CPUs with EM64T extension, and a
common 64bit userspace.
* arm64: supports the latest 64-bit ARM-powered devices.
* armel: little-endian ARM machines.
* armhf: an alternative to armel for ARMv7 machines with
hard-float.
* i386: this covers systems based on Intel and compatible
processors, including Intel's 386, 486, Pentium, Pentium Pro,
Pentium II (both Klamath and Celeron), and Pentium III, and
most compatible processors by AMD, Cyrix and others.
* ia64: Intel IA-64 ("Itanium") computers.
* mips: SGI's big-endian MIPS systems, Indy and Indigo2; mipsel
: little-endian MIPS machines, Digital DECstations.
* powerpc: this covers some IBM/Motorola PowerPC machines,
including the Apple Macintosh PowerMac models, and the CHRP
and PReP open architecture machines.
* ppc64el: 64-bit little-endian PowerPC port, supports several
recent PowerPC/POWER processors.
* s390x: 64-bit port for IBM System z machines, replaced s390.
The development of binary distributions of Debian for hurd-i386
(for GNU Hurd kernel on i386 32-bit PCs), mipsel64 (for 64 bit
MIPS in little-endian mode), powerpcspe (port for the "Signal
Processing Engine" hardware), sparc64 (for 64 bit SPARC
processors), sh (for Hitachi SuperH processors), and x32 (for
amd64/x86_64 CPUs using 32-bit pointers) is currently underway.
Support for the m68k architecture was dropped in the Etch (Debian
4.0) release, because it did not meet the criteria set by the
Debian Release Managers. This architecture covers Amigas and
ATARIs having a Motorola 680x0 processor for x>=2; with MMU.
However, the port is still active and available for installation
even if not a part of this official stable release and might be
reactivated for future releases.
Support for the hppa (Hewlett-Packard's PA-RISC machines) and
alpha (Compaq/Digital's Alpha systems) were dropped in the
Squeeze (Debian 6.0) release for similar reasons. The arm was
dropped too in this release, as it was superseded by the armel
architecture.
Support for the 32-bit s390 port (s390) was discontinued and
replaced with s390x in Jessie (Debian 8). In addition, the ports
to IA-64 and Sparc had to be removed from this release due to
insufficient developer support.
For more information on the available ports see the ports pages
at the website (https://www.debian.org/ports/) .
For further information on booting, partitioning your drive,
enabling PCMCIA (PC Card) devices and similar issues please
follow the instructions given in the Installation Manual, which
is available from our WWW site at https://www.debian.org/releases
/stable/installmanual (https://www.debian.org/releases/stable/
installmanual) .
4.2. What kernels does Debian GNU/Linux run?
Beside Linux, Debian provides a complete, binary distribution for
the following operating system kernels:
* FreeBSD: provided through the kfreebsd-amd64 and
kfreebsd-i386 ports, for 64-bit PCs and 32-bit PCs
respectively. These ports were first released in Debian 6.0
Squeeze as a technology preview. However they were not part
of the Debian 8 Jessie release.
In addition to these, work is in progress on the following
adaptations:
* avr32, port to Atmel's 32-bit RISC architecture,
* hurd-i386, a port for 32-bit PC. This port will use GNU Hurd,
the new operating system being put together by the GNU group,
* sh, port to Hitachi SuperH processors.
There were attempts to port the distribution to the NetBSD
kernel, providing netbsd-i386 (for 32-bit PCs) and netbsd-alpha
(for Alpha machines) but these ports were never released and are
currently abandoned.
For more information on the available ports see the ports pages
at the website (https://www.debian.org/ports/) .
4.3. How compatible is Debian with other distributions of Linux?
Debian developers communicate with other Linux distribution
creators in an effort to maintain binary compatibility across
Linux distributions. ^[1] Most commercial Linux products run as
well under Debian as they do on the system upon which they were
built.
Debian GNU/Linux adheres to the Linux Filesystem Hierarchy
Standard (https://www.pathname.com/fhs) . However, there is room
for interpretation in some of the rules within this standard, so
there may be slight differences between a Debian system and other
Linux systems.
4.4. How source code compatible is Debian with other Unix systems?
For most applications Linux source code is compatible with other
Unix systems. It supports almost everything that is available in
System V Unix systems and the free and commercial BSD-derived
systems. However in the Unix business such claim has nearly no
value because there is no way to prove it. In the software
development area complete compatibility is required instead of
compatibility in "about most" cases. So years ago the need for
standards arose, and nowadays POSIX.1 (IEEE Standard 1003.1-1990)
is one of the major standards for source code compatibility in
Unix-like operating systems.
Linux is intended to adhere to POSIX.1, but the POSIX standards
cost real money and the POSIX.1 (and FIPS 151-2) certification is
quite expensive; this made it more difficult for the Linux
developers to work on complete POSIX conformance. The
certification costs make it unlikely that Debian will get an
official conformance certification even if it completely passed
the validation suite. (The validation suite is now freely
available, so it is expected that more people will work on
POSIX.1 issues.)
Unifix GmbH (Braunschweig, Germany) developed a Linux system that
has been certified to conform to FIPS 151-2 (a superset of
POSIX.1). This technology was available in Unifix' own
distribution called Unifix Linux 2.0 and in Lasermoon's Linux-FT.
4.5. Can I use Debian packages (".deb" files) on my Red Hat/Slackware
/... Linux system? Can I use Red Hat packages (".rpm" files) on my
Debian GNU/Linux system?
Different Linux distributions use different package formats and
different package management programs.
You probably can:
A program to unpack a Debian package onto a Linux host that
is been built from a `foreign' distribution is available, and
will generally work, in the sense that files will be
unpacked. The converse is probably also true, that is, a
program to unpack a Red Hat or Slackware package on a host
that is based on Debian GNU/Linux will probably succeed in
unpacking the package and placing most files in their
intended directories. This is largely a consequence of the
existence (and broad adherence to) the Linux Filesystem
Hierarchy Standard. The Alien (https://packages.debian.org/
alien) package is used to convert between different package
formats.
You probably do not want to:
Most package managers write administrative files when they
are used to unpack an archive. These administrative files are
generally not standardized. Therefore, the effect of
unpacking a Debian package on a `foreign' host will have
unpredictable (certainly not useful) effects on the package
manager on that system. Likewise, utilities from other
distributions might succeed in unpacking their archives on
Debian systems, but will probably cause the Debian package
management system to fail when the time comes to upgrade or
remove some packages, or even simply to report exactly what
packages are present on a system.
A better way:
The Linux File System Standard (and therefore Debian GNU/
Linux) requires that subdirectories under /usr/local/ be
entirely under the user's discretion. Therefore, users can
unpack `foreign' packages into this directory, and then
manage their configuration, upgrade and removal individually.
4.6. How should I install a non-Debian program?
Files under the directory /usr/local/ are not under the control
of the Debian package management system. Therefore, it is good
practice to place the source code for your program in /usr/local/
src/. For example, you might extract the files for a package
named "foo.tar" into the directory /usr/local/src/foo. After you
compile them, place the binaries in /usr/local/bin/, the
libraries in /usr/local/lib/, and the configuration files in /usr
/local/etc/.
If your programs and/or files really must be placed in some other
directory, you could still store them in /usr/local/, and build
the appropriate symbolic links from the required location to its
location in /usr/local/, e.g., you could make the link
ln -s /usr/local/bin/foo /usr/bin/foo
In any case, if you obtain a package whose copyright allows
redistribution, you should consider making a Debian package of
it, and uploading it for the Debian system. Guidelines for
becoming a package developer are included in the Debian Policy
manual (see Section 12.1, “What other documentation exists on and
for a Debian system?”).
---------------------------------------------------------------------
^[1] The Linux Standard Base (https://wiki.linuxfoundation.org/
lsb/start/) is a specification for allowing the same binary
package to be used on multiple distributions. After Jessie
(Debian 8) was released, Debian abandoned (https://
sources.debian.org/src/lsb/9.20170808/debian/README.Debian/) the
pursuit of LSB compatibility. See this July 3, 2015 message from
Didier Raboud (https://lists.debian.org/
4526217.myWFlvm1rM@gyllingar) and the following discussion for
background information.
Chapter 5. Software available in the Debian system
5.1. What types of applications and development software are
available for Debian GNU/Linux?
Like most Linux distributions, Debian GNU/Linux provides:
* the major GNU applications for software development, file
manipulation, and text processing, including gcc, g++, make,
texinfo, Emacs, the Bash shell and numerous upgraded Unix
utilities,
* Perl, Python, Tcl/Tk and various related programs, modules
and libraries for each of them,
* TeX (LaTeX) and Lyx, dvips, Ghostscript,
* the Xorg windowing system, which provides a networked
graphical user interface for Linux, and countless X
applications including the GNOME, KDE and Xfce desktop
environments,
* a full suite of networking applications, including servers
for Internet protocols such as HTTP (WWW), FTP, NNTP (news),
SMTP and POP (mail) and DNS (name servers); relational
databases like PostgreSQL, MySQL; also provided are web
browsers including the various Mozilla products,
* a complete set of office applications, including the
LibreOffice productivity suite, Gnumeric and other
spreadsheets, WYSIWYG editors, calendars.
More than 58100 packages, ranging from news servers and readers
to sound support, FAX programs, database and spreadsheet
programs, image processing programs, communications, net, and
mail utilities, Web servers, and even ham-radio programs are
included in the distribution. Other 1000 software suites are
available as Debian packages, but are not formally part of Debian
due to license restrictions.
5.2. Who wrote all that software?
For each package the authors of the program(s) are credited in
the file /usr/share/doc/PACKAGE/copyright, where PACKAGE is to be
substituted with the package's name.
Maintainers who package this software for the Debian GNU/Linux
system are listed in the Debian control file (see Section 7.4,
“What is a Debian control file?”) that comes with each package.
The Debian changelog, in /usr/share/doc/PACKAGE/
changelog.Debian.gz, mentions the people who've worked on the
Debian packaging too.
5.3. How can I get a current list of programs that have been packaged
for Debian?
A complete list is available from any of the Debian mirrors
(https://www.debian.org/distrib/ftplist) , in the file indices/
Maintainers. That file includes the package names and the names
and e-mails of their respective maintainers.
The WWW interface to the Debian packages (https://
packages.debian.org/) conveniently summarizes the packages in
each of about thirty "sections" of the Debian archive.
5.4. How can I install a developer's environment to build packages?
If you want to build packages in your Debian system you will need
to have a basic development environment, including a C/C++
compiler and some other essential packages. In order to install
this environment you just need to install the build-essential
package. This is a meta-package or place-holder package which
depends on the standard development tools one needs to build a
Debian package.
Some software can, however, need additional software to be
rebuilt, including library headers or additional tools such as
autoconf or gettext. Debian provides many of the tools needed to
build other software as Debian packages.
Finding which software is precisely required can be tricky,
however, unless you are planning on rebuilding Debian packages.
This last task is rather easy to do, as official packages have to
include a list of the additional software (besides the packages
in build-essential) needed to build the package, this is known as
Build-Dependencies. To install all the packages needed to build a
given source package and then build said source package you can
just run:
# apt-get build-dep foo
# apt-get source --build foo
Notice that if you want to build the Linux kernels distributed by
Debian you will want to install also the kernel-package package.
For more information see Section 10.2, “What tools does Debian
provide to build custom kernels?”.
5.5. What is missing from Debian GNU/Linux?
There is a list of packages which still need to be packaged for
Debian, the Work-Needing and Prospective Packages list (https://
www.debian.org/devel/wnpp/) .
For more details about adding missing things, see Chapter 13,
Contributing to the Debian Project.
5.6. Why do I get "ld: cannot find -lfoo" messages when compiling
programs? Why aren't there any libfoo.so files in Debian library
packages?
Debian Policy requires that such symbolic links (to
libfoo.so.x.y.z or similar) are placed in separate, development
packages. Those packages are usually named libfoo-dev or
libfooX-dev (presuming the library package is named libfooX, and
X is a whole number).
5.7. (How) Does Debian support Java?
Several free implementations of Java technology are available as
Debian packages, providing both Java Development Kits as well as
Runtime Environments. You can write, debug and run Java programs
using Debian.
Running a Java applet requires a web browser with the capability
to recognize and execute it. Several web browsers available in
Debian, such as Mozilla or Konqueror, support Java plug-ins that
enable running Java applets within them.
Please refer to the Debian Java FAQ (https://www.debian.org/doc/
manuals/debian-java-faq/) for more information.
5.8. How can I check that I am using a Debian system, and what
version it is?
In order to make sure that your system has been installed from
the real Debian base disks, use the
lsb_release -a
command. It will display the name of the distribution (in
Distributor ID field) and the version of the system (in Release
and Codename fields). The following is an example run in a Debian
system:
$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 7.4 (wheezy)
Release: 7.4
Codename: wheezy
You can also check for the existence of /etc/debian_version file,
which contains a single one-line entry giving the version number
of the release, as defined by the package base-files.
Users should be aware, however, that the Debian system consists
of many parts, each of which can be updated (almost)
independently. Each Debian "release" contains well defined and
unchanging contents. Updates are separately available. For a
one-line description of the installation status of package foo,
use the command dpkg --list foo. For a more verbose description,
use:
dpkg --status foo
To view versions of all installed packages, run:
dpkg -l
Note that the existence of the program dpkg shows that you should
be able to install Debian packages on your system. However, since
the program has been ported to many other operating systems and
architectures, this is no longer a reliable method of determining
if a system is Debian GNU/Linux.
5.9. How does Debian support non-English languages?
* Debian GNU/Linux is distributed with keymaps for nearly two
dozen keyboards, and with utilities (in the kbd package) to
install, view, and modify the tables.
The installation prompts the user to specify the keyboard to
use.
* Nearly all of the software in Debian supports UTF-8 as
character set. Legacy character sets, such as ISO-8859-1 or
ISO-8859-2, should be considered obsolete.
* Currently, support for German-, Spanish-, French-,
Hungarian-, Italian-, Japanese-, Korean-, Dutch-, Polish-,
Portuguese-, Russian-, Turkish-, and Chinese-language manual
pages is provided through the manpages-LANG packages (where
LANG is the two-letter ISO country code). To access an NLS
manual page, the user must set the shell LC_MESSAGES variable
to the appropriate string.
For example, in the case of the Italian-language manual
pages, LC_MESSAGES needs to be set to 'italian'. The man
program will then search for Italian manual pages under /usr/
share/man/it/.
5.10. Where is ezmlm/djbdns/qmail?
Dan J. Bernstein used to distribute all software he has written
(https://cr.yp.to/software.html) with a restrictive license which
does not allow modified binaries to be distributed. In november
2007 however, Bernstein said "[...] i have decided to put all of
my future and [...] past software into the public domain". See
FAQ from distributors (https://cr.yp.to/distributors.html) for
his distribution terms.
As of this writing (2016-03), ezmlm-idx is available in
experimental only (mlmmj is similar, and shipped with Debian
jessie); djbdns is available in sid (unstable) only, see Bug #
516394 (https://bugs.debian.org/516394) and Bug #796118 (https://
bugs.debian.org/796118) for details and see dbndns for a similar
alternative; the publicfile software is still not free software,
a publicfile-installer package is available from Debian's contrib
section.
Other software of Dan J. Bernstein (qmail, daemontools, ucspi-tcp
) is shipped with Debian.
5.11. Where is a player for Flash (SWF)?
Debian ships both gnash and swfdec: two free SWF movie players.
5.12. Where is Google Earth?
Google Earth is available for GNU/Linux from Google's web site,
but not only it is not Free Software, but is completely
undistributable by a third party. However, googleearth-package
(in the contrib-section) might be helpful in using this software.
5.13. Where is VoIP software?
Two main open protocols are used for Voice Over IP: SIP and
H.323. Both are implemented by a wide variety of software in
Debian main. ekiga is one of the popular clients.
5.14. I have a wireless network card which doesn't work with Linux.
What should I do?
Buy one which does :)
Alternatively, use ndiswrapper to use a driver for Windows (if
you have one) on your Linux system. See the Debian Wiki
ndiswrapper page (https://wiki.debian.org/NdisWrapper) for more
information.
Chapter 6. The Debian archives
6.1. How many Debian distributions are there?
There are three major distributions: the "stable" distribution,
the "testing" distribution, and the "unstable" distribution. The
"testing" distribution is sometimes `frozen' (see Section 6.5.1,
“What about "testing"? How is it `frozen'?”). Next to these,
there is the "oldstable" distribution (that's just the one from
before "stable"), and the "experimental" distribution.
Experimental is used for packages which are still being
developed, and with a high risk of breaking your system. It's
used by developers who'd like to study and test bleeding edge
software. Users shouldn't be using packages from there, because
they can be dangerous and harmful even for the most experienced
people.
See Chapter 3, Choosing a Debian distribution for help when
choosing a Debian distribution.
6.2. What are all those names like etch, lenny, etc.?
They are just "codenames". When a Debian distribution is in the
development stage, it has no version number but a codename. The
purpose of these codenames is to make easier the mirroring of the
Debian distributions (if a real directory like unstable suddenly
changed its name to stable, a lot of stuff would have to be
needlessly downloaded again).
Currently, stable is a symbolic link to bullseye (i.e. Debian GNU
/Linux 11) and testing is a symbolic link to bookworm. This means
that bullseye is the current stable distribution and bookworm is
the current testing distribution.
unstable is a permanent symbolic link to sid, as sid is always
the unstable distribution (see Section 6.3, “What about "sid"?”).
6.2.1. Which other codenames have been used in the past?
Aside bullseye and bookworm, other codenames that have been
already used are: buzz for release 1.1, rex for release 1.2, bo
for releases 1.3.x, hamm for release 2.0, slink for release 2.1,
potato for release 2.2, woody for release 3.0, sarge for release
3.1, etch for release 4.0, lenny for release 5.0, squeeze for
release 6.0, wheezy for release 7, jessie for release 8, stretch
for release 9, buster for release 10.
6.2.2. Where do these codenames come from?
So far they have been characters taken from the "Toy Story"
movies by Pixar.
* buzz (Debian 1.1) was the spaceman Buzz Lightyear,
* rex (Debian 1.2) was the tyrannosaurus,
* bo (Debian 1.3) was Bo Peep, the girl who took care of the
sheep,
* hamm (Debian 2.0) was the piggy bank,
* slink (Debian 2.1) was Slinky Dog, the toy dog,
* potato (Debian 2.2) was, of course, Mr. Potato,
* woody (Debian 3.0) was the cowboy,
* sarge (Debian 3.1) was the sergeant of the Green Plastic Army
Men,
* etch (Debian 4.0) was the toy whiteboard (Etch-a-Sketch),
* lenny (Debian 5.0) was the toy binoculars,
* squeeze (Debian 6) was the name of the three-eyed aliens,
* wheezy (Debian 7) was the rubber toy penguin with a red bow
tie,
* jessie (Debian 8) was the yodeling cowgirl,
* stretch (Debian 9) was the rubber toy octopus with suckers on
her eight long arms.
* buster (Debian 10) was Andy's pet dog.
* bullseye (Debian 11) was Woody's wooden toyhorse.
* bookworm (Debian 12) was a green toy worm with a built-in
flashlight who loves reading books.
* trixie (Debian 13) was a blue plastic triceratops.
* sid was the evil neighbor kid next door who broke all toys.
The decision (https://lists.debian.org/debian-devel/1996/06/
msg00515.html) of using Toy Story names was made (https://
lists.debian.org/debian-user/1997/04/msg00011.html) by Bruce
Perens who was, at the time, the Debian Project Leader and was
working also at Pixar, the company that produced the movies.
6.3. What about "sid"?
sid or unstable is the place where most of the packages are
initially uploaded. It will never be released directly, because
packages which are to be released will first have to be included
in testing, in order to be released in stable later on. sid
contains packages for both released and unreleased architectures.
The name "sid" also comes from the "Toy Story" animated motion
picture: Sid was the boy next door who destroyed toys :-)
^[2]
6.4. What does the stable directory contain?
* stable/main/: This directory contains the packages which
formally constitute the most recent release of the Debian GNU
/Linux system.
These packages all comply with the Debian Free Software
Guidelines (https://www.debian.org/social_contract#
guidelines) , and are all freely usable and distributable.
* stable/non-free/: This directory contains packages
distribution of which is restricted in a way that requires
that distributors take careful account of the specified
copyright requirements.
For example, some packages have licenses which prohibit
commercial distribution. Others can be redistributed but are
in fact shareware and not free software. The licenses of each
of these packages must be studied, and possibly negotiated,
before the packages are included in any redistribution (e.g.,
in a CD-ROM).
* stable/contrib/: This directory contains packages which are
DFSG-free and freely distributable themselves, but somehow
depend on a package that is not freely distributable and thus
available only in the non-free section.
6.5. What does the testing distribution contain?
Packages are installed into the `testing' directory after they
have undergone some degree of testing in unstable.
They must be in sync on all architectures where they have been
built and mustn't have dependencies that make them uninstallable;
they also need to have fewer release-critical bugs than the
versions currently in unstable. This way, we hope that `testing'
is always close to being a release candidate.
More information about the status of "testing" in general and the
individual packages is available at https://www.debian.org/devel/
testing (https://www.debian.org/devel/testing) .
6.5.1. What about "testing"? How is it `frozen'?
When the "testing" distribution is mature enough, the release
manager starts `freezing' it. The normal propagation delays are
increased to ensure that as few new bugs as possible from
"unstable" enter "testing".
After a while, the "testing" distribution becomes truly `frozen'.
This means that all new packages that are to propagate to the
"testing" are held back, unless they include release-critical bug
fixes. The "testing" distribution can also remain in such a deep
freeze during the so-called `test cycles', when the release is
imminent.
When a "testing" release becomes `frozen', "unstable" tends to
partially freeze as well. This is because developers are
reluctant to upload radically new software to unstable, in case
the frozen software in testing needs minor updates and to fix
release critical bugs which keep testing from becoming "stable".
We keep a record of bugs in the "testing" distribution that can
hold off a package from being released, or bugs that can hold
back the whole release. For details, please see current testing
release information (https://www.debian.org/releases/testing/) .
Once that bug count lowers to maximum acceptable values, the
frozen "testing" distribution is declared "stable" and released
with a version number.
The most important bug count is the "Release Critical" bug count,
which can be followed in the Release-critical bug status page
(https://bugs.debian.org/release-critical/) . A common release
goal is NoRCBugs (https://wiki.debian.org/ReleaseGoals/NoRCBugs)
which means that the distribution should not have any bugs of
severity critical, grave or serious. The full list of issues
considered critical can be found in the RC policy document
(https://release.debian.org/testing/rc_policy.txt) .
With each new release, the previous "stable" distribution becomes
obsolete and moves to the archive. For more information please
see Debian archive (https://www.debian.org/distrib/archive) .
6.6. What does the unstable distribution contain?
The `unstable' directory contains a snapshot of the current
development system. Users are welcome to use and test these
packages, but are warned about their state of readiness. The
advantage of using the unstable distribution is that you are
always up-to-date with the latest in GNU/Linux software industry,
but if it breaks: you get to keep both parts :-)
There are also main, contrib and non-free subdirectories in
`unstable', separated on the same criteria as in `stable'.
6.7. What are all those directories at the Debian archives?
The software that has been packaged for Debian GNU/Linux is
available in one of several directory trees on each Debian mirror
site.
The dists directory is short for "distributions", and it is the
canonical way to access the currently available Debian releases
(and pre-releases).
The pool directory contains the actual packages, see
Section 6.10, “What's in the pool directory?”.
There are the following supplementary directories:
/tools/:
DOS utilities for creating boot disks, partitioning your disk
drive, compressing/decompressing files, and booting Linux.
/doc/:
The basic Debian documentation, such as this FAQ, the bug
reporting system instructions, etc.
/indices/:
various indices of the site (the Maintainers file and the
override files).
/project/:
mostly developer-only materials and some miscellaneous files.
6.8. What are all those directories inside dists/stable/main?
Within each of the major directory trees^[3], there are three
sets of subdirectories containing index files.
There's one set of binary-something subdirectories which contain
index files for binary packages of each available computer
architecture, for example binary-i386 for packages which execute
on Intel x86 PC machines or binary-sparc for packages which
execute on Sun SPARCStations.
The complete list of available architectures for each release is
available at the release's web page (https://www.debian.org/
releases) . For the current release, please see Section 4.1, “On
what hardware architectures/systems does Debian GNU/Linux run?”.
The index files in binary-* are called Packages(.gz, .bz2) and
they include a summary of each binary package that is included in
that distribution. The actual binary packages reside in the top
level pool directory.
Furthermore, there's a subdirectory called source/ which contains
index files for source packages included in the distribution. The
index file is called Sources(.gz, .bz2).
Last but not least, there's a set of subdirectories meant for the
installation system index files, they are at debian-installer/
binary-architecture.
6.9. Where is the source code?
Source code is included for everything in the Debian system.
Moreover, the license terms of most programs in the system
require that source code be distributed along with the programs,
or that an offer to provide the source code accompany the
programs.
The source code is distributed in the pool directory (see
Section 6.10, “What's in the pool directory?”) together with all
the architecture-specific binary directories. To retrieve the
source code without having to be familiar with the structure of
the archive, try a command like apt-get source mypackagename.
Due to restrictions in their licenses, source code may or may not
be available for packages in the "contrib" and "non-free" areas,
which are not formally part of the Debian system. In some cases
only sourceless "binary blobs" can be distributed (see for
instance firmware-misc-nonfree); in other cases the license
prohibits the distribution of prebuilt binaries, but does allow
packages of source code which users can compile locally (see
broadcom-sta-dkms).
6.10. What's in the pool directory?
Packages are kept in a large `pool', structured according to the
name of the source package. To make this manageable, the pool is
subdivided by section (`main', `contrib' and `non-free') and by
the first letter of the source package name. These directories
contain several files: the binary packages for each architecture,
and the source packages from which the binary packages were
generated.
You can find out where each package is placed by executing a
command like apt-cache showsrc mypackagename and looking at the
`Directory:' line. For example, the apache packages are stored in
pool/main/a/apache/.
Additionally, since there are so many lib* packages, these are
treated specially: for instance, libpaper packages are stored in
pool/main/libp/libpaper/.
^[4]
6.11. What is "incoming"?
After a developer uploads a package, it stays for a short while
in the "incoming" directory before it is checked that it's
genuine and allowed into the archive.
Usually nobody should install things from this place. However, in
some rare cases of emergency, the incoming directory is available
at https://incoming.debian.org/ (https://incoming.debian.org/) .
You can manually fetch packages, check the GPG signature and
MD5sums in the .changes and .dsc files, and then install them.
6.12. How do I set up my own apt-able repository?
If you have built some private Debian packages which you'd like
to install using the standard Debian package management tools,
you can set up your own apt-able package archive. This is also
useful if you'd like to share your Debian packages while these
are not distributed by the Debian project. Instructions on how to
do this are given on the Debian Wiki (https://wiki.debian.org/
HowToSetupADebianRepository) .
---------------------------------------------------------------------
^[2] When the present-day sid did not exist, the FTP site
organization had one major flaw: there was an assumption that
when an architecture is created in the current unstable, it will
be released when that distribution becomes the new stable. For
many architectures that isn't the case, with the result that
those directories had to be moved at release time. This was
impractical because the move would chew up lots of bandwidth.
The archive administrators worked around this problem for several
years by placing binaries for unreleased architectures in a
special directory called "sid". For those architectures not yet
released, the first time they were released there was a link from
the current stable to sid, and from then on they were created
inside the unstable tree as normal. This layout was somewhat
confusing to users.
With the advent of package pools (see Section 6.10, “What's in
the pool directory?”), binary packages began to be stored in a
canonical location in the pool, regardless of the distribution,
so releasing a distribution no longer causes large bandwidth
consumption on the mirrors (there is, however, a lot of gradual
bandwidth consumption throughout the development process).
^[3] dists/stable/main, dists/stable/contrib, dists/stable/
non-free, and dists/unstable/main/, etc.
^[4] Historically, packages were kept in the subdirectory of
dists corresponding to which distribution contained them. This
turned out to cause various problems, such as large bandwidth
consumption on mirrors when major changes were made. This was
fixed with the introduction of the package pool.
The dists directories are still used for the index files used by
programs like apt.
Chapter 7. Basics of the Debian package management system
This chapter touches on some lower level internals of Debian
package management. If you're interested mainly in usage of the
relevant tools, skip to chapters Chapter 8, The Debian package
management tools and/or Chapter 9, Keeping your Debian system
up-to-date.
7.1. What is a Debian package?
Packages generally contain all of the files necessary to
implement a set of related commands or features. There are two
types of Debian packages:
* Binary packages, which contain executables, configuration
files, man/info pages, copyright information, and other
documentation. These packages are distributed in a
Debian-specific archive format (see Section 7.2, “What is the
format of a Debian binary package?”); they are usually
characterized by having a '.deb' file extension. Binary
packages can be unpacked using the Debian utility dpkg
(possibly via a frontend like aptitude); details are given in
its manual page.
* Source packages, which consist of a .dsc file describing the
source package (including the names of the following files),
a .orig.tar.gz file that contains the original unmodified
source in gzip-compressed tar format and usually a .diff.gz
file that contains the Debian-specific changes to the
original source. The utility dpkg-source packs and unpacks
Debian source archives; details are provided in its manual
page. (The program apt-get can be used as a frontend for
dpkg-source.)
Installation of software by the package system uses
"dependencies" which are carefully designed by the package
maintainers. These dependencies are documented in the control
file associated with each package. For example, the package
containing the GNU C compiler (gcc) "depends" on the package
binutils which includes the linker and assembler. If a user
attempts to install gcc without having first installed binutils,
the package management system (dpkg) will send an error message
that it also needs binutils, and stop installing gcc. (However,
this facility can be overridden by the insistent user, see dpkg
(8).) See more in Section 7.9, “What is meant by saying that a
package Depends, Recommends, Suggests, Conflicts, Replaces,
Breaks or Provides another package?” below.
Debian's packaging tools can be used to:
* manipulate and manage packages or parts of packages,
* administer local overrides of files in a package,
* aid developers in the construction of package archives, and
* aid users in the installation of packages which reside on a
remote archive site.
7.2. What is the format of a Debian binary package?
A Debian "package", or a Debian archive file, contains the
executable files, libraries, and documentation associated with a
particular suite of program or set of related programs. Normally,
a Debian archive file has a filename that ends in .deb.
The internals of this Debian binary packages format are described
in the deb(5) manual page. This internal format is subject to
change (between major releases of Debian GNU/Linux), therefore
please always use dpkg-deb(1) if you need to do lowlevel
manipulations on .deb files.
7.3. Why are Debian package file names so long?
The Debian binary package file names conform to the following
convention: <foo>_<VersionNumber>-<DebianRevisionNumber>_
<DebianArchitecture>.deb
Note that foo is supposed to be the package name. Checking the
package name associated with a particular Debian archive file
(.deb file) can be done in one of these ways:
* inspect the "Packages" file in the directory where it was
stored at a Debian archive site. This file contains a stanza
describing each package; the first field in each stanza is
the formal package name.
* use the command dpkg --info foo_VVV-RRR_AAA.deb (where VVV,
RRR and AAA are the version, revision and architecture of the
package in question, respectively). This displays, among
other things, the package name corresponding to the archive
file being unpacked.
The VVV component is the version number specified by the upstream
developer. There are no standards in place here, so the version
number may have formats as different as "19990513" and
"1.3.8pre1".
The RRR component is the Debian revision number, and is specified
by the Debian developer (or a user who chooses to rebuild the
package locally). This number corresponds to the revision level
of the Debian package, thus, a new revision level usually
signifies changes in the Debian Makefile (debian/rules), the
Debian control file (debian/control), the installation or removal
scripts (debian/p*), or in the configuration files used with the
package.
The AAA component identifies the processor for which the package
was built. This is commonly amd64, which refers to AMD64, Intel
64 or VIA Nano chips. For other possibilities review Debian's
archive directory structure at Section 6.7, “What are all those
directories at the Debian archives?”. For details, see the
description of "Debian architecture" in the manual page
dpkg-architecture(1).
7.4. What is a Debian control file?
Specifics regarding the contents of a Debian control file are
provided in the Debian Policy Manual, section 5, see
Section 12.1, “What other documentation exists on and for a
Debian system?”.
Briefly, a sample control file is shown below for the Debian
package hello:
Package: hello
Version: 2.9-2+deb8u1
Architecture: amd64
Maintainer: Santiago Vila <sanvila@debian.org>
Installed-Size: 145
Depends: libc6 (>= 2.14)
Conflicts: hello-traditional
Breaks: hello-debhelper (<< 2.9)
Replaces: hello-debhelper (<< 2.9), hello-traditional
Section: devel
Priority: optional
Homepage: https://www.gnu.org/software/hello/
Description: example package based on GNU hello
The GNU hello program produces a familiar, friendly greeting. It
allows non-programmers to use a classic computer science tool which
would otherwise be unavailable to them.
.
Seriously, though: this is an example of how to do a Debian package.
It is the Debian version of the GNU Project's `hello world' program
(which is itself an example for the GNU Project).
The Package field gives the package name. This is the name by
which the package can be manipulated by the package tools, and
usually similar to but not necessarily the same as the first
component string in the Debian archive file name.
The Version field gives both the upstream developer's version
number and (in the last component) the revision level of the
Debian package of this program as explained in Section 7.3, “Why
are Debian package file names so long?”.
The Architecture field specifies the chip for which this
particular binary was compiled.
The Depends field gives a list of packages that have to be
installed in order to install this package successfully.
The Installed-Size indicates how much disk space the installed
package will consume. This is intended to be used by installation
front-ends in order to show whether there is enough disk space
available to install the program.
The Section line gives the "section" where this Debian package is
stored at the Debian archive sites.
The Priority indicates how important is this package for
installation, so that semi-intelligent software like apt or
aptitude can sort the package into a category of e.g. packages
optionally installed. See Section 7.7, “What is an Essential,
Required, Important, Standard, Optional, or Extra package?”.
The Maintainer field gives the e-mail address of the person who
is currently responsible for maintaining this package.
The Description field gives a brief summary of the package's
features.
For more information about all possible fields a package can
have, please see the Debian Policy Manual, section 5, "Control
files and their fields", see Section 12.1, “What other
documentation exists on and for a Debian system?”.
7.5. What is a Debian conffile?
Conffiles is a list of configuration files (usually placed in /
etc) that the package management system will not overwrite when
the package is upgraded. This ensures that local values for the
contents of these files will be preserved, and is a critical
feature enabling the in-place upgrade of packages on a running
system.
To determine exactly which files are preserved during an upgrade,
run:
dpkg --status package
And look under "Conffiles:".
7.6. What is a Debian preinst, postinst, prerm, and postrm script?
These files are executable scripts which are automatically run
before or after a package is installed or removed. Along with a
file named control, all of these files are part of the "control"
section of a Debian archive file.
The individual files are:
preinst
This script is executed before the package it belongs to is
unpacked from its Debian archive (".deb") file. Many
'preinst' scripts stop services for packages which are being
upgraded until their installation or upgrade is completed
(following the successful execution of the 'postinst'
script).
postinst
This script typically completes any required configuration of
the package foo once foo has been unpacked from its Debian
archive (".deb") file. Often, 'postinst' scripts ask users
for input, and/or warn them that if they accept default
values, they should remember to go back and re-configure that
package as needed. Many 'postinst' scripts then execute any
commands necessary to start or restart a service once a new
package has been installed or upgraded.
prerm
This script typically stops any daemons which are associated
with a package. It is executed before the removal of files
associated with the package.
postrm
This script typically modifies links or other files
associated with foo, and/or removes files created by the
package. (Also see Section 7.8, “What is a Virtual Package?”
.)
Currently all of the control files can be found in the directory
/var/lib/dpkg/info. The files relevant to package foo begin with
the name "foo" and have file extensions of "preinst", "postinst",
etc., as appropriate. The file foo.list in that directory lists
all of the files that were installed with the package foo. (Note
that the location of these files is a dpkg internal; you should
not rely on it.)
7.7. What is an Essential, Required, Important, Standard, Optional,
or Extra package?
Each Debian package is assigned a priority by the distribution
maintainers, as an aid to the package management system. The
priorities are:
* Required: packages that are necessary for the proper
functioning of the system.
This includes all tools that are necessary to repair system
defects. You must not remove these packages or your system
may become totally broken and you may probably not even be
able to use dpkg to put things back. Systems with only the
Required packages are probably unusable, but they do have
enough functionality to allow the sysadmin to boot and
install more software.
* Important packages should be found on any Unix-like system.
Other packages which the system will not run well or be
usable without will be here. This does NOT include Emacs or X
or TeX or any other large application. These packages only
constitute the bare infrastructure.
* Standard packages are standard on any Linux system, including
a reasonably small but not too limited character-mode system.
Tools are included to be able to send e-mail (with mutt) and
download files from archive servers.
This is what will be installed by default if users do not
select anything else. It does not include many large
applications, but it does include the Python interpreter and
some server software like OpenSSH (for remote administration)
and Exim (for mail delivery, although it can be configured
for local delivery only). It also includes some common
generic documentation that most users will find helpful.
* Optional packages include all those that you might reasonably
want to install if you do not know what they are, or that do
not have specialized requirements.
This includes X, a full TeX distribution, and lots of
applications.
* Extra: packages that either conflict with others with higher
priorities, are only likely to be useful if you already know
what they are, or have specialized requirements that make
them unsuitable for "Optional".
If you do a default Debian installation all the packages of
priority Standard or higher will be installed in your system. If
you select pre-defined tasks you will get lower priority packages
too.
Additionally, some packages are marked as Essential since they
are absolutely necessary for the proper functioning of the
system. The package management tools will refuse to remove these.
7.8. What is a Virtual Package?
A virtual package is a generic name that applies to any one of a
group of packages, all of which provide similar basic
functionality. For example, both the konqueror and firefox-esr
programs are web browsers, and should therefore satisfy any
dependency of a program that requires a web browser on a system,
in order to work or to be useful. They are therefore both said to
provide the "virtual package" called www-browser.
Similarly, exim4 and sendmail both provide the functionality of a
mail transport agent. They are therefore said to provide the
virtual package "mail-transport-agent". If either one is
installed, then any program depending on the installation of a
mail-transport-agent will be satisfied by the presence of this
virtual package.
Debian provides a mechanism so that, if more than one package
which provide the same virtual package is installed on a system,
then system administrators can set one as the preferred package.
The relevant command is update-alternatives, and is described
further in Section 11.11, “Some users like mawk, others like
gawk; some like vim, others like elvis; some like trn, others
like tin; how does Debian support diversity?”.
7.9. What is meant by saying that a package Depends, Recommends,
Suggests, Conflicts, Replaces, Breaks or Provides another package?
The Debian package system has a range of package "dependencies"
which are designed to indicate (in a single flag) the level at
which Program A can operate independently of the existence of
Program B on a given system:
* Package A depends on Package B if B absolutely must be
installed in order to run A. In some cases, A depends not
only on B, but on a version of B. In this case, the version
dependency is usually a lower limit, in the sense that A
depends on any version of B more recent than some specified
version.
* Package A recommends Package B, if the package maintainer
judges that most users would not want A without also having
the functionality provided by B.
* Package A suggests Package B if B contains files that are
related to (and usually enhance) the functionality of A.
* Package A conflicts with Package B when A will not operate if
B is installed on the system. Most often, conflicts are cases
where A contains files which are an improvement over those in
B. "Conflicts" are often combined with "replaces".
* Package A replaces Package B when files installed by B are
removed and (in some cases) over-written by files in A.
* Package A breaks Package B when both packages cannot be
simultaneously configured in a system. The package management
system will refuse to install one if the other one is already
installed and configured in the system.
* Package A provides Package B when all of the files and
functionality of B are incorporated into A. This mechanism
provides a way for users with constrained disk space to get
only that part of package A which they really need.
More detailed information on the use of each of these terms can
be found in the Debian Policy manual, section 7.2, "Binary
Dependencies", see Section 12.1, “What other documentation exists
on and for a Debian system?”.
7.10. What is meant by Pre-Depends?
"Pre-Depends" is a special dependency. In the case of most
packages, dpkg will unpack the archive file of a package (i.e.,
its .deb file) independently of whether or not the files on which
it depends exist on the system. Simplistically, unpacking means
that dpkg will extract the files from the archive file that were
meant to be installed on your file system, and put them in place.
If those packages depend on the existence of some other packages
on your system, dpkg will refuse to complete the installation (by
executing its "configure" action) until the other packages are
installed.
However, for some packages, dpkg will refuse even to unpack them
until certain dependencies are resolved. Such packages are said
to "Pre-depend" on the presence of some other packages. The
Debian project provided this mechanism to support the safe
upgrading of systems from a.out format to ELF format, where the
order in which packages were unpacked was critical. There are
other large upgrade situations where this method is useful, e.g.
the packages with the required priority and their LibC
dependency.
As before, more detailed information about this can be found in
the Policy manual.
7.11. What is meant by unknown, install, remove, purge and hold in
the package status?
These "want" flags tell what the user wanted to do with a package
(as indicated by the user's direct invocations of dpkg/apt/
aptitude).
Their meanings are:
* unknown - the user has never indicated whether the package is
wanted.
* install - the user wants the package installed or upgraded.
* remove - the user wants the package removed, but does not
want to remove any existing configuration file.
* purge - the user wants the package to be removed completely,
including its configuration files.
* hold - the user wants this package not to be processed, i.e.
wants to keep the current version with the current status
whatever that is.
7.12. How do I put a package on hold?
There are three ways of holding back packages, with dpkg, apt or
aptitude.
With dpkg, you have to export the list of package selections,
with:
dpkg --get-selections \* > selections.txt
Then edit the resulting file selections.txt, change the line
containing the package you wish to hold, e.g. libc6, from this:
libc6 install
to this:
libc6 hold
Save the file, and reload it into dpkg database with:
dpkg --set-selections < selections.txt
With apt, you can set a package to hold using
apt-mark hold package_name
and remove the hold with
apt-mark unhold package_name
With aptitude, you can hold a package using
aptitude hold package_name
and remove the hold with
aptitude unhold package_name
7.13. How do I install a source package?
Debian source packages can't actually be "installed", they are
just unpacked in whatever directory you want to build the binary
packages they produce.
Source packages are distributed on most of the same mirrors where
you can obtain the binary packages. If you set up your APT's
sources.list(5) to include the appropriate "deb-src" lines,
you'll be able to easily download any source package by running
apt-get source foo
To help you in actually building the source package, Debian
source packages provide the so-called build-dependencies
mechanism. This means that the source package maintainer keeps a
list of other packages that are required to build their package.
To see how this is useful, run
apt-get build-dep foo
before building the source.
7.14. How do I build binary packages from a source package?
The preferred way to do this is by using various wrapper tools.
We'll show how it's done using the devscripts tools. Install this
package if you haven't done so already.
Now, first get the source package:
apt-get source foo
and change to the source tree:
cd foo-*
Then install needed build-dependencies (if any):
sudo apt-get build-dep foo
Then create a dedicated version of your own build (so that you
won't get confused later when Debian itself releases a new
version):
dch -l local 'Blah blah blah'
And finally build your package:
debuild -us -uc
If everything worked out fine, you should now be able to install
your package by running
sudo dpkg -i ../*.deb
If you prefer to do things manually, and don't want to use
devscripts, follow this procedure:
You will need all of foo_*.dsc, foo_*.tar.gz and foo_*.diff.gz to
compile the source (note: there is no .diff.gz for some packages
that are native to Debian).
Once you have them (Section 7.13, “How do I install a source
package?”) and if you have the dpkg-dev package installed, the
following command:
dpkg-source -x foo_version-revision.dsc
will extract the package into a directory called foo-version.
If you just want to compile the package, you may cd into the
foo-version directory and issue the command
dpkg-buildpackage -rfakeroot -b
to build the package (note that this also requires the fakeroot
package), and then
dpkg -i ../foo_version-revision_arch.deb
to install the newly-built package(s).
7.15. How do I create Debian packages myself?
For a more detailed description on this, read the New
Maintainers' Guide, available in the maint-guide package or at
https://www.debian.org/doc/devel-manuals#maint-guide (https://
www.debian.org/doc/devel-manuals#maint-guide) , or the Guide for
Debian Maintainers, available in the debmake-doc package or at
https://www.debian.org/doc/devel-manuals#debmake-doc (https://
www.debian.org/doc/devel-manuals#debmake-doc) .
Chapter 8. The Debian package management tools
8.1. What programs does Debian provide for managing its packages?
There are multiple tools that are used to manage Debian packages,
from graphic or text-based interfaces to the low level tools used
to install packages. All the available tools rely on the lower
level tools to properly work and are presented here in decreasing
complexity level.
It is important to understand that the higher level package
management tools such as aptitude or synaptic rely on apt which,
itself, relies on dpkg to manage the packages in the system.
See Chapter 2. Debian package management (https://www.debian.org/
doc/manuals/debian-reference/ch02.en.html) of the Debian
reference (https://www.debian.org/doc/manuals/debian-reference/)
for more information about the Debian package management
utilities. This document is available in various languages and
formats, see the Debian Reference entry in the DDP Users' Manuals
overview (https://www.debian.org/doc/user-manuals#
quick-reference) .
8.1.1. dpkg
This is the main package management program. dpkg can be invoked
with many options. Some common uses are:
* Find out all the options: dpkg --help.
* Print out the control file (and other information) for a
specified package: dpkg --info foo_VVV-RRR.deb.
* Install a package (including unpacking and configuring) onto
the file system of the hard disk: dpkg --install
foo_VVV-RRR.deb.
* Unpack (but do not configure) a Debian archive into the file
system of the hard disk: dpkg --unpack foo_VVV-RRR.deb. Note
that this operation does not necessarily leave the package in
a usable state; some files may need further customization to
run properly. This command removes any already-installed
version of the program and runs the preinst (see Section 7.6,
“What is a Debian preinst, postinst, prerm, and postrm
script?”) script associated with the package.
* Configure a package that already has been unpacked: dpkg
--configure foo. Among other things, this action runs the
postinst (see Section 7.6, “What is a Debian preinst,
postinst, prerm, and postrm script?”) script associated with
the package. It also updates the files listed in the
conffiles for this package. Notice that the 'configure'
operation takes as its argument a package name (e.g., foo),
not the name of a Debian archive file (e.g.,
foo_VVV-RRR.deb).
* Extract a single file named "blurf" (or a group of files
named "blurf*") from a Debian archive: dpkg --fsys-tarfile
foo_VVV-RRR.deb | tar -xf - 'blurf*'.
* Remove a package (but not its configuration files): dpkg
--remove foo.
* Remove a package (including its configuration files): dpkg
--purge foo.
* List the installation status of packages containing the
string (or regular expression) "foo*": dpkg --list 'foo*'.
8.1.2. APT
APT is the Advanced Package Tool, an advanced interface to the
Debian packaging system which provides the apt-get program. It
provides commandline tools for searching and managing packages,
and for querying information about them, as well as low-level
access to all features of the libapt-pkg library. For more
information, see the User's Guide in /usr/share/doc/apt-doc/
guide.html/index.html (you will have to install the apt-doc
package).
Starting with Debian Jessie, some frequently used apt-get and
apt-cache commands have an equivalent via the new apt binary.
This means some popular commands like apt-get update, apt-get
install, apt-get remove, apt-cache search, or apt-cache show now
can also be called simply via apt, say apt update, apt install,
apt remove, apt search, or apt show. The following is an overview
of the old and new commands:
apt-get update -> apt update
apt-get upgrade -> apt upgrade
apt-get dist-upgrade -> apt full-upgrade
apt-get install package -> apt install package
apt-get remove package -> apt remove package
apt-get autoremove -> apt autoremove
apt-cache search string -> apt search string
apt-cache policy package -> apt list -a package
apt-cache show package -> apt show package
apt-cache showpkg package -> apt show -a package
The apt tool merges functionality of apt-get and apt-cache and by
default has a fancier colored output format, making it more
pleasant for humans. For usage in scripts or advanced use cases,
apt-get is still preferable or needed.
apt-get provides a simple way to retrieve and install packages
from multiple sources using the command line. Unlike dpkg,
apt-get does not understand .deb files, it works with the
packages proper name and can only install .deb archives from a
source specified in /etc/apt/sources.list. apt-get will call dpkg
directly after downloading the .deb archives^[5] from the
configured sources.
Some common ways to use apt-get are:
* To update the list of packages known by your system, you can
run:
apt update
(you should execute this regularly to update your package
lists)
* To install the foo package and all its dependencies, run:
apt install foo
* To remove the foo package from your system, run:
apt remove foo
* To remove the foo package and its configuration files from
your system, run:
apt purge foo
* To list all packages for which newer versions are available,
run:
apt list --upgradable
* To upgrade all the packages on your system (without
installing extra packages or removing packages), run:
apt upgrade
* To upgrade all the packages on your system, and, if needed
for a package upgrade, installing extra packages or removing
packages, run:
apt full-upgrade
(The command upgrade keeps a package at its installed
obsolete version if upgrading would need an extra package to
be installed, for a new dependency to be satisfied. The
full-upgrade command is less conservative.)
Note that you must be logged in as root to perform any commands
that modify packages.
Note that apt-get now also installs recommended packages as
default, and thanks to its robustness it's the preferred program
for package management from console to perform system
installation and major system upgrades.
The apt tool suite also includes the apt-cache tool to query the
package lists. You can use it to find packages providing specific
functionality through simple text or regular expression queries
and through queries of dependencies in the package management
system. Some common ways to use apt-cache are:
* To find packages whose description contain word:
apt search word
* To print the detailed information of a package:
apt show package
* To print the packages a given package depends on:
apt-cache depends package
* To print detailed information on the versions available for a
package and the packages that reverse-depends on it:
apt-cache showpkg package
For more information, install the apt package and read apt(8),
apt-get(8), sources.list(5) and install the apt-doc package and
read /usr/share/doc/apt-doc/guide.html/index.html.
8.1.3. aptitude
aptitude is a package manager for Debian GNU/Linux systems that
provides a frontend to the apt package management infrastructure.
aptitude is a text-based interface using the curses library.
Actions may be performed from a visual interface or from the
command-line.
aptitude can be used to perform management tasks in a fast and
easy way. It allows the user to view the list of packages and to
perform package management tasks such as installing, upgrading,
and removing packages.
aptitude provides the functionality of apt-get, as well as many
additional features:
* aptitude offers easy access to all versions of a package.
* aptitude makes it easy to keep track of obsolete software by
listing it under "Obsolete and Locally Created Packages".
* aptitude includes a fairly powerful system for searching
particular packages and limiting the package display. Users
familiar with mutt will pick up quickly, as mutt was the
inspiration for the expression syntax.
* aptitude can be used to install the predefined tasks
available. For more information see Section 8.1.5, “tasksel”.
* aptitude in full screen mode has su functionality embedded
and can be run by a normal user. It will call su (and ask for
the root password, if any) when you really need
administrative privileges.
You can use aptitude through a visual interface (simply run
aptitude) or directly from the command line. The command line
syntax used is very similar to the one used in apt-get. For
example, to install the foo package, you can run aptitude install
foo.
Note that aptitude is the preferred program for daily package
management from the console.
For more information, read the manual page aptitude(8) and
install the aptitude-doc package.
8.1.4. synaptic
synaptic is a graphical package manager. It enables you to
install, upgrade and remove software packages in a user friendly
way. Along with most of the features offered by aptitude, it also
has a feature for editing the list of used repositories, and
supports browsing all available documentation related to a
package. See the Synaptic Website (https://www.nongnu.org/
synaptic/) for more information.
8.1.5. tasksel
When you want to perform a specific task it might be difficult to
find the appropiate suite of packages that fill your need. The
Debian developers have defined tasks, a task is a collection of
several individual Debian packages all related to a specific
activity. Tasks can be installed through the tasksel program or
through aptitude.
Typically, the Debian installer will automatically install the
task associated with a standard system and a desktop environment.
The specific desktop environment installed will depend on the CD/
DVD media used, most commonly it will be the GNOME desktop
(gnome-desktop task). Also, depending on your selections
throughout the installation process, tasks might be automatically
installed in your system. For example, if you selected a language
other than English, the task associated with it will be installed
automatically too.
8.1.6. Other package management tools
8.1.6.1. dpkg-deb
This program manipulates Debian archive (.deb) files. Some common
uses are:
* Find out all the options: dpkg-deb --help.
* Determine what files are contained in a Debian archive file:
dpkg-deb --contents foo_VVV-RRR.deb)
* Extract the files contained in a named Debian archive into a
user specified directory: dpkg-deb --extract foo_VVV-RRR.deb
tmp extracts each of the files in foo_VVV-RRR.deb into the
directory tmp/. This is convenient for examining the contents
of a package in a localized directory, without installing the
package into the root file system.
* Extract the control information files from a package:
dpkg-deb --control foo_VVV-RRR.deb tmp.
Note that any packages that were merely unpacked using dpkg-deb
--extract will be incorrectly installed, you should use dpkg
--install instead.
More information is given in the manual page dpkg-deb(1).
8.2. Debian claims to be able to update a running program; how is
this accomplished?
The kernel (file system) in Debian GNU/Linux systems supports
replacing files even while they're being used.
We also provide a program called start-stop-daemon which is used
to start daemons at boot time or to stop daemons when the
runlevel is changed (e.g., from multi-user to single-user or to
halt). The same program is used by installation scripts when a
new package containing a daemon is installed, to stop running
daemons, and restart them as necessary.
8.3. How can I tell what packages are already installed on a Debian
system?
To learn the status of all the packages installed on a Debian
system, execute the command
dpkg --list
This prints out a one-line summary for each package, giving a
2-letter status symbol (explained in the header), the package
name, the version which is installed, and a brief description.
To learn the status of packages whose names match any pattern
beginning with "foo", run the command:
dpkg --list 'foo*'
To get a more verbose report for a particular package, execute
the command:
dpkg --status packagename
8.4. How do I display the files of an installed package?
To list all the files provided by the installed package foo
execute the command
dpkg --listfiles foo
Note that the files created by the installation scripts aren't
displayed.
8.5. How can I find out what package produced a particular file?
To identify the package that produced the file named foo execute
either:
* dpkg --search foo
This searches for foo in installed packages. (This is
(currently) equivalent to searching all of the files having
the file extension of .list in the directory /var/lib/dpkg/
info/, and adjusting the output to print the names of all the
packages containing it, and diversions.)
A faster alternative to this is the dlocate tool.
dlocate -S foo
* zgrep foo Contents-ARCH.gz
This searches for files which contain the substring foo in
their full path names. The files Contents-ARCH.gz (where ARCH
represents the wanted architecture) reside in the major
package directories (main, non-free, contrib) at a Debian
archive site (i.e. under /debian/dists/bullseye). A Contents
file refers only to the packages in the subdirectory tree
where it resides. Therefore, a user might have to search more
than one Contents files to find the package containing the
file foo.
This method has the advantage over dpkg --search in that it
will find files in packages that are not currently installed
on your system.
* apt-file search foo
If you install the apt-file package, similar to the above, it
searches files which contain the substring or regular
expression foo in their full path names. The advantage over
the example above is that there is no need to retrieve the
Contents-ARCH.gz files as it will do this automatically for
all the sources defined in /etc/apt/sources.list when you run
(as root) apt-file update.
8.6. Why is `foo-data' not removed when I uninstall `foo'? How do I
make sure old unused library-packages get purged?
Some packages are split in program (`foo') and data (`foo-data')
(or in `foo' and `foo-doc'). This is true for many games,
multimedia applications and dictionaries in Debian and has been
introduced since some users might want to access the raw data
without installing the program or because the program can be run
without the data itself, making `foo-data' optional.
Similar situations occur when dealing with libraries: generally
these get installed since packages containing applications depend
on them. When the application-package is purged, the
library-package might stay on the system. Or: when the
application-package no longer depends upon e.g. libdb4.2, but
upon libdb4.3, the libdb4.2 package might stay when the
application-package is upgraded.
In these cases, `foo-data' doesn't depend on `foo', so when you
remove the `foo' package it will not get automatically removed by
most package management tools. The same holds true for the
library packages. This is necessary to avoid circular
dependencies. However, if you use apt-get (see Section 8.1.2,
“APT”) or aptitude (see Section 8.1.3, “aptitude”) as your
package management tool, they will track automatically installed
packages and give the possibility to remove them, when no
packages making use of them remain in your system.
---------------------------------------------------------------------
^[5] Notice that there are ports that make this tool available
with other package management systems, like Red Hat package
manager, also known as rpm
Chapter 9. Keeping your Debian system up-to-date
One of Debian's goals is to provide a consistent upgrade path and
a secure upgrade process. We always do our best to make upgrading
to new releases a smooth procedure. In case there's some
important note to add to the upgrade process, the packages will
alert the user, and often provide a solution to a possible
problem.
You should also read the Release Notes document that describes
the details of specific upgrades. It is available on the Debian
website at https://www.debian.org/releases/stable/releasenotes
(https://www.debian.org/releases/stable/releasenotes) and is also
shipped on the Debian CDs, DVDs and Blu-ray discs.
9.1. How can I keep my Debian system current?
One could simply visit a Debian archive site, then peruse the
directories until one finds the desired file, and then fetch it,
and finally install it using dpkg. Note that dpkg will install
upgrade files in place, even on a running system. Sometimes, a
revised package will require the installation of a newly revised
version of another package, in which case the installation will
fail until/unless the other package is installed.
Many people find this approach much too time-consuming, since
Debian evolves so quickly -- typically, a dozen or more new
packages are uploaded every week. This number is larger just
before a new major release. To deal with this avalanche, many
people prefer to use a more automated method. Several different
packages are available for this purpose:
9.1.1. aptitude
aptitude is the recommended package manager for Debian GNU/Linux
systems, and is described in Section 8.1.3, “aptitude”.
Before you can use aptitude to make an upgrade, you'll have to
edit the /etc/apt/sources.list file to set it up. If you wish to
upgrade to the latest stable version of Debian, you'll probably
want to use a source like this one:
http://ftp.us.debian.org/debian stable main contrib
You can replace ftp.us.debian.org (the mirror in the United
States) with the name of a faster Debian mirror near you. See the
mirror list at https://www.debian.org/mirror/list (https://
www.debian.org/mirror/list) for more information.
Or you can use the redirector service httpredir.debian.org which
aims to solve the problem of choosing a Debian mirror. It uses
the geographic location of the user and other information to
choose the best mirror that can serve the files. To take
advantage of it use a source like this one:
http://httpredir.debian.org/debian stable main contrib
More details on this can be found in the sources.list(5) manual
page.
To update your system from the command line, run
aptitude update
followed by
aptitude full-upgrade
Answer any questions that might come up, and your system will be
upgraded.
Note that aptitude is not the recommended tool for doing upgrades
from one Debian GNU/Linux release to another. Use apt-get
instead. For upgrades between releases you should read the
Release Notes (https://www.debian.org/releases/stable/
releasenotes) . This document describes in detail the recommended
steps for upgrades from previous releases as well as known issues
you should consider before upgrading.
For details, see the manual page aptitude(8), and the file /usr/
share/aptitude/README.
9.1.2. apt-get and apt-cdrom
An alternative to aptitude is apt-get which is an APT-based
command-line tool (described previously in Section 8.1.2, “APT”).
apt-get, the APT-based command-line tool for handling packages,
provides a simple, safe way to install and upgrade packages.
To use apt-get, edit the /etc/apt/sources.list file to set it up,
just as for Section 9.1.1, “aptitude”.
Then run
apt-get update
followed by
apt-get dist-upgrade
Answer any questions that might come up, and your system will be
upgraded. See also the apt-get(8) manual page, as well as
Section 8.1.2, “APT”.
If you want to use CDs/DVDs/BDs to install packages, you can use
apt-cdrom. For details, please see the Release Notes, section
"Adding APT sources from optical media".
Please note that when you get and install the packages, you'll
still have them kept in your /var directory hierarchy. To keep
your partition from overflowing, remember to delete extra files
using apt-get clean and apt-get autoclean, or to move them
someplace else (hint: use apt-move).
9.2. Must I go into single user mode in order to upgrade a package?
No. Packages can be upgraded in place, even in running systems.
Debian has a start-stop-daemon program that is invoked to stop,
then restart running process if necessary during a package
upgrade.
9.3. Do I have to keep all those .deb archive files on my disk?
No. If you have downloaded the files to your disk then after you
have installed the packages, you can remove them from your
system, e.g. by running aptitude clean.
9.4. How can I keep a log of the packages I added to the system? I'd
like to know when upgrades and removals have occurred and on which
packages!
Passing the --log-option to dpkg makes dpkg log status change
updates and actions. It logs both the dpkg-invokation (e.g.
2005-12-30 18:10:33 install hello 1.3.18 2.1.1-4
) and the results (e.g.
2005-12-30 18:10:35 status installed hello 2.1.1-4
) If you'd like to log all your dpkg invocations (even those done
using frontends like aptitude), you could add
log /var/log/dpkg.log
to your /etc/dpkg/dpkg.cfg. Be sure the created logfile gets
rotated periodically. If you're using logrotate, this can be
achieved by creating a file /etc/logrotate.d/dpkg with the
following lines
/var/log/dpkg {
missingok
notifempty
}
More details on dpkg logging can be found in the dpkg(1) manual
page.
aptitude logs the package installations, removals, and upgrades
that it intends to perform to /var/log/aptitude. Note that the
results of those actions are not recorded in this file!
Another way to record your actions is to run your package
management session within the script(1) program.
9.5. Can I automatically update the system?
Yes. You can use cron-apt; this tool updates the system at
regular intervals using a cron job. By default it just updates
the package list and downloads new packages, but without
installing them.
Note: Automatic upgrade of packages is NOT recommended in testing
or unstable systems as this might bring unexpected behaviour and
remove packages without notice.
9.6. I have several machines; how can I download the updates only one
time?
If you have more than one Debian machine on your network, it is
useful to use apt-cacher to keep all of your Debian systems
up-to-date.
apt-cacher reduces the bandwidth requirements of Debian mirrors
by restricting the frequency of Packages, Releases and Sources
file updates from the back end and only doing a single fetch for
any file, independently of the actual request from the proxy.
apt-cacher automatically builds a Debian HTTP mirror based on
requests which pass through the proxy.
Of course, you can get the same benefit if you are already using
a standard caching proxy and all your systems are configured to
use it.
Chapter 10. Debian and the kernel
10.1. Can I install and compile a kernel without some Debian-specific
tweaking?
Yes.
There's only one common catch: the Debian C libraries are built
with the most recent stable releases of the kernel headers. If
you happen to need to compile a program with kernel headers newer
than the ones from the stable branch, then you should either
upgrade the package containing the headers (linux-libc-dev), or
use the new headers from an unpacked tree of the newer kernel.
That is, if the kernel sources are in /usr/src/linux, then you
should add -I/usr/src/linux/include/ to your command line when
compiling.
10.2. What tools does Debian provide to build custom kernels?
Users who wish to (or must) build a custom kernel are encouraged
to use the Debian package target included with recent versions of
the kernel build system. After configuring the kernel, simply run
the following command:
make deb-pkg
The new kernel package will be created in the directory one level
above the kernel source tree, and it may be installed using dpkg
-i.
Users must separately download the source code for the most
recent kernel (or the kernel of their choice) from their favorite
Linux archive site, unless a linux-source-version package is
available (where version stands for the kernel version).
10.3. What special provisions does Debian provide to deal with
modules?
A configuration file containing modules to be manually loaded at
boot time is kept at /etc/modules. However, editing this file is
rarely needed.
Other module configuration is kept in the /etc/modprobe.d/
directory. More information about the format of those files can
be found in the modprobe.conf(5) manual page.
10.4. Can I safely de-install an old kernel package, and if so, how?
Yes. The linux-image-NNN.prerm script checks to see whether the
kernel you are currently running is the same as the kernel you
are trying to de-install. Therefore you can remove unwanted
kernel image packages using this command:
dpkg --purge linux-image-NNN
(replace NNN with your kernel version and revision number, of
course)
10.5. Where can I get more information about Linux packages for
Debian?
Further information is maintained in the Debian Linux Kernel
Handbook (https://kernel-team.pages.debian.net/kernel-handbook/)
.
Chapter 11. Customizing your Debian GNU/Linux system
11.1. How can I ensure that all programs use the same paper size?
Install the libpaper1 package, and it will ask you for a
system-wide default paper size. This setting will be kept in the
file /etc/papersize.
Users can override the paper size setting using the PAPERSIZE
environment variable. For details, see the manual page papersize
(5).
11.2. How can I provide access to hardware peripherals, without
compromising security?
Many device files in the /dev directory belong to some predefined
groups. For example, /dev/sr0 belongs to the cdrom group.
If you want a certain user to have access to one of these
devices, just add the user to the group the device belongs to,
i.e. do:
adduser user group
This way you won't have to change the file permissions on the
device.
If you do this from within a user's shell or a GUI environment
you have to logout and login again to become an effective member
of that group. To check which groups you belong to run groups.
Notice that, since the introduction of udev if you change the
permissions of a hardware peripheral, they might be adjusted for
some devices when the system starts; if this happens to the
hardware peripherals you are interested in, you will have to
adjust the rules at /etc/udev.
11.3. How do I load a console font on startup the Debian way?
The kbd package supports this, edit the /etc/kbd/config file.
11.4. How can I configure an X11 program's application defaults?
Debian's X programs will install their application resource data
in the /etc/X11/app-defaults/ directory. If you want to customize
X applications globally, put your customizations in those files.
They are marked as configuration files, so their contents will be
preserved during upgrades.
11.5. How does a Debian system boot?
Like all Unices, Debian boots up by executing the program init.
Like most Linux distributions, a default Debian system uses
systemd as the implementation of init. Traditional System-V style
init and other methods are also supported. ^[6]
To control the order in which services are started, traditional
System-V style Unix systems use runlevels. These are replaced by
targets under systemd. To display the default target to which
systemd will bring the system, run the command
systemctl get-default
During boot-up, systemd starts the services or other targets
listed in the default target file /lib/systemd/system/
default.target. The files for these services and targets are
installed and the service is enabled during Debian package
installation. If you specifically wish not to start a service
during boot-up, instead of removing the corresponding package,
you can run the command
systemctl disable service.service
using the name of the service file installed in /lib/systemd/
system (usually based on the name of the package).
The service file /lib/systemd/system/rc-local.service provides an
easy way to run customized scripts in the file /etc/rc.local
after boot-up, similar to what's offered on Debian systems
running System-V style init. Beware: this script will fail if it
tries to interact with the console such as asking for a user
password or trying to clear the screen.
You can check the status of any service by the command
service package status
. To start or stop a service, run
service package start
and
service package stop
. The service command works with any init system supported on a
Debian system, not just with systemd. If you however prefer to
use the same command on any systemd-supported Linux system, for
checking the status run
systemctl status package.service
to get the same information.
For more information on systemd for Debian, see https://
wiki.debian.org/systemd (https://wiki.debian.org/systemd) .
11.6. And how about Debian and traditional System V init?
Debian supports booting using traditional System V init, via the
sysvinit-core package. The configuration file for System V init
(which is /etc/inittab) specifies that the first script to be
executed should be /etc/init.d/rcS. This script runs all of the
scripts in /etc/rcS.d/ by forking subprocesses to perform
initialization such as to check and to mount file systems, to
load modules, to start the network services, to set the clock,
and to perform other initialization.
After completing the boot process, init executes all start
scripts in a directory specified by the default runlevel (this
runlevel is given by the entry for id in /etc/inittab). Like most
System V compatible Unices, Linux has 7 runlevels:
* 0 (halt the system),
* 1 (single-user mode),
* 2 through 5 (various multi-user modes), and
* 6 (reboot the system).
Debian systems come with id=2, which indicates that the default
runlevel will be '2' when the multi-user state is entered, and
the scripts in /etc/rc2.d/ will be run.
Debian uses dependency-based boot ordering through insserv, using
the LSB headers in each script under /etc/init.d/, as well as
parallel concurrent booting through the use of startpar to speed
up the boot process.
The scripts in any of the directories, /etc/rcN.d/ are just
symbolic links back to scripts in /etc/init.d/. However, the
names of the files in each of the /etc/rcN.d/ directories are
selected to indicate the way the scripts in /etc/init.d/ will be
run. Specifically, before entering any runlevel, all the scripts
beginning with 'K' are run; these scripts kill services. Then all
the scripts beginning with 'S' are run; these scripts start
services. The two-digit number following the 'K' or 'S' indicates
the order in which the script is run. Lower numbered scripts are
executed first.
This approach works because the scripts in /etc/init.d/ all take
an argument which can be either `start', `stop', `reload',
`restart' or `force-reload' and will then do the task indicated
by the argument. These scripts can be used even after a system
has been booted, to control various processes.
For example, with the argument `reload' the command
/etc/init.d/sendmail reload
sends the sendmail daemon a signal to reread its configuration
file.
Note that invoke-rc.d should not be used to call the /etc/init.d/
scripts, service should be used instead.
11.7. And are there yet other ways of booting a Debian system?
If you do like System V init, but don't like the /etc/rc?.d/*
links, you could install the file-rc package. That will convert
the links into one single configuration file /etc/runlevel.conf
instead.
If you like neither System V nor systemd, you might like openrc
or runit or daemontools.
11.8. How does the package management system deal with packages that
contain configuration files for other packages?
Some users wish to create, for example, a new server by
installing a group of Debian packages and a locally generated
package consisting of configuration files. This is not generally
a good idea, because dpkg will not know about those configuration
files if they are in a different package, and may write
conflicting configurations when one of the initial "group" of
packages is upgraded.
Instead, create a local package that modifies the configuration
files of the "group" of Debian packages of interest. Then dpkg
and the rest of the package management system will see that the
files have been modified by the local "sysadmin" and will not try
to overwrite them when those packages are upgraded.
11.9. How do I override a file installed by a package, so that a
different version can be used instead?
Suppose a sysadmin or local user wishes to use a program
"login-local" rather than the program "login" provided by the
Debian login package.
Do not:
* Overwrite /bin/login with login-local.
The package management system will not know about this change,
and will simply overwrite your custom /bin/login whenever login
(or any package that provides /bin/login) is installed or
updated.
Rather, do
* Execute:
dpkg-divert --divert /bin/login.debian /bin/login
in order to cause all future installations of the Debian
login package to write the file /bin/login to /bin/
login.debian instead.
* Then execute:
cp login-local /bin/login
to move your own locally-built program into place.
Run dpkg-divert --list to see which diversions are currently
active on your system.
Details are given in the manual page dpkg-divert(8).
11.10. How can I have my locally-built package included in the list
of available packages that the package management system knows about?
Execute the command:
dpkg-scanpackages BIN_DIR OVERRIDE_FILE [PATHPREFIX] > my_Packages
where:
* BIN-DIR is a directory where Debian archive files (which
usually have an extension of ".deb") are stored.
* OVERRIDE_FILE is a file that is edited by the distribution
maintainers and is usually stored on a Debian archive at
indices/override.main.gz for the Debian packages in the
"main" distribution. You can ignore this for local packages.
* PATHPREFIX is an optional string that can be prepended to the
my_Packages file being produced.
Once you have built the file my_Packages, tell the package
management system about it by using the command:
dpkg --merge-avail my_Packages
If you are using APT, you can add the local repository to your
sources.list(5) file, too.
11.11. Some users like mawk, others like gawk; some like vim, others
like elvis; some like trn, others like tin; how does Debian support
diversity?
There are several cases where two packages provide two different
versions of a program, both of which provide the same core
functionality. Users might prefer one over another out of habit,
or because the user interface of one package is somehow more
pleasing than the interface of another. Other users on the same
system might make a different choice.
Debian uses a "virtual" package system to allow system
administrators to choose (or let users choose) their favorite
tools when there are two or more that provide the same basic
functionality, yet satisfy package dependency requirements
without specifying a particular package.
For example, there might exist two different versions of
newsreaders on a system. The news server package might
'recommend' that there exist some news reader on the system, but
the choice of tin or trn is left up to the individual user. This
is satisfied by having both the tin and trn packages provide the
virtual package news-reader. Which program is invoked is
determined by a link pointing from a file with the virtual
package name /etc/alternatives/news-reader to the selected file,
e.g., /usr/bin/trn.
A single link is insufficient to support full use of an alternate
program; normally, manual pages, and possibly other supporting
files must be selected as well. The Perl script
update-alternatives provides a way of ensuring that all the files
associated with a specified package are selected as a system
default.
For example, to check what executables provide
`x-window-manager', run:
update-alternatives --display x-window-manager
If you want to change it, run:
update-alternatives --config x-window-manager
And follow the instructions on the screen (basically, press the
number next to the entry you'd like better).
If a package doesn't register itself as a window manager for some
reason (file a bug if it's in error), or if you use a window
manager from /usr/local directory, the selections on screen won't
contain your preferred entry. You can update the link through
command line options, like this:
update-alternatives --install /usr/bin/x-window-manager \
x-window-manager /usr/local/bin/wmaker-cvs 50
The first argument to `--install' option is the symlink that
points to /etc/alternatives/NAME, where NAME is the second
argument. The third argument is the program to which /etc/
alternatives/NAME should point to, and the fourth argument is the
priority (larger value means the alternative will more probably
get picked automatically).
To remove an alternative you added, simply run:
update-alternatives --remove x-window-manager /usr/local/bin/wmaker-cvs
---------------------------------------------------------------------
^[6] In 2014, Debian changed its default init system from System
V init to systemd. Debian 8 "jessie" in April 2015 was the first
release to ship with systemd as default init. Four decisions
(https://www.debian.org/devel/tech-ctte#status) of the Debian
Technical Committee were involved: Bug #727708 (https://
lists.debian.org/20140211193904.GX24404@rzlab.ucr.edu)
2014-02-11: "The committee decided that the default init system
for Linux architectures in jessie should be systemd." Bug #746715
(https://lists.debian.org/
20140801023630.GF12356@teltox.donarmstrong.com) 2014-08-01: "The
technical committee expects maintainers to continue to support
the multiple available init systems", and merge reasonable
contributions. Bug #746578 (https://lists.debian.org/
20141116001628.GO32192@teltox.donarmstrong.com) 2014-11-15: "The
committee decided that systemd-shim should be the first listed
alternative dependency of libpam-systemd instead of
systemd-sysv." This decision made it easier to keep running a
non-systemd Debian system. Bug #762194 (https://lists.debian.org/
21592.61064.527547.410074@chiark.greenend.org.uk) 2017-11-04: "On
automatic init system switching on upgrade"
Chapter 12. Getting support for Debian GNU/Linux
12.1. What other documentation exists on and for a Debian system?
* Installation instructions for the current release: see https:
//www.debian.org/releases/stable/installmanual (https://
www.debian.org/releases/stable/installmanual) .
* The Debian GNU/Linux reference covers many aspects of system
administration through shell-command examples. Basic
tutorials, tips, and other information are provided for many
different topics ranging from system administration to
programming.
Get it from the debian-reference package, or at https://
www.debian.org/doc/user-manuals#quick-reference (https://
www.debian.org/doc/user-manuals#quick-reference) .
* The Debian Policy manual documents the policy requirements
for the distribution, i.e. the structure and contents of the
Debian archive, several design issues of the operating system
etc. It also includes the technical requirements that each
package must satisfy to be included in the distribution, and
documents the basic technical aspects of Debian binary and
source packages.
Get it from the debian-policy package, or at https://
www.debian.org/doc/devel-manuals#policy (https://
www.debian.org/doc/devel-manuals#policy) .
* Documentation developed by the Debian Documentation Project.
It is available at https://www.debian.org/doc (https://
www.debian.org/doc) and includes user guides, administration
guides and security guides for the Debian GNU/Linux operating
system.
* Documentation on installed Debian packages: Most packages
have files that are unpacked into /usr/share/doc/PACKAGE.
* Documentation on the Linux project: The Debian package
doc-linux installs all of the most recent versions of the
HOWTOs and mini-HOWTOs from the Linux Documentation Project
(http://www.tldp.org/) .
* Unix-style `man' pages: Most commands have manual pages
written in the style of the original Unix 'man' files. For
instance, to see the manual page for the command `ls',
execute man ls. Execute man man for more information on
finding and viewing manual pages.
New Debian users should note that the 'man' pages of many
general system commands are not available until they install
these packages:
+ man-db, which contains the man program itself, and other
programs for manipulating the manual pages.
+ manpages, which contains the system manual pages. (see
Section 5.9, “How does Debian support non-English
languages?”).
* GNU-style `info' pages: User documentation for many commands,
particularly GNU tools, is available not in `man' pages, but
in `info' files which can be read by the GNU tool info, by
running M-x info within GNU Emacs, or with some other Info
page viewer.
Its main advantage over the original `man' pages is that it
is a hypertext system. It does not require the WWW, however;
info can be run from a plain text console. It was designed by
Richard Stallman and preceded the WWW.
Note that you may access a lot of documentation on your system by
using a WWW browser, through `dwww', `dhelp' or `doccentral'
commands, found in respective packages, or by using `yelp'.
12.2. Are there any on-line resources for discussing Debian?
Yes. In fact, the main method of support Debian provides to our
users is by the way of e-mail. We'll give some details on that,
and mention some other useful resources. Even more resources are
listed at the Debian Support webpage (https://www.debian.org/
support) .
12.2.1. Mailing lists
There are a lot of Debian-related mailing lists (https://
www.debian.org/MailingLists/) .
On a system with the doc-debian package installed there is a
complete list of mailing lists in /usr/share/doc/debian/
mailing-lists.txt.
Debian mailing lists are named following the pattern debian-
list-subject. Examples are debian-announce, debian-user,
debian-news. To subscribe to any list debian-list-subject, send
mail to debian-list-subject-request@lists.debian.org with the
word "subscribe" in the Subject: header. Be sure to remember to
add -request to the e-mail address when using this method to
subscribe or unsubscribe. Otherwise your e-mail will go to the
list itself, which could be embarrassing or annoying, depending
on your point of view.
You can subscribe to mailing lists using the WWW form (https://
www.debian.org/MailingLists/subscribe) . You can also
un-subscribe using a WWW form (https://www.debian.org/
MailingLists/unsubscribe) .
The list manager's e-mail address is <listmaster@lists.debian.org
>, in case you have any trouble.
The mailing lists are public forums. All e-mails sent to the
lists are also copied to the public archive, for anybody (even
non-subscribers) to browse or search. Please make sure you never
send any confidential or unlicensed material to the lists. This
includes things like e-mail addresses. Of particular note is the
fact that spammers have been known to abuse e-mail addresses
posted to our mailing lists. See the Mailing Lists Privacy policy
(https://www.debian.org/MailingLists/#disclaimer) for more
information.
Archives of the Debian mailing lists are available via WWW at
https://lists.debian.org/ (https://lists.debian.org/) .
12.2.1.1. What is the code of conduct for the mailing lists?
When using the Debian mailing lists, please follow these rules:
* Do not send spam. See the Debian mailing list advertising
policy (https://www.debian.org/MailingLists/#ads) .
* Do not flame; it is not polite. The people developing Debian
are all volunteers, donating their time, energy and money in
an attempt to bring the Debian project together.
* Do not use foul language; besides, some people receive the
lists via packet radio, where swearing is illegal.
* Make sure that you are using the proper list. Never post your
(un)subscription requests to the mailing list itself.^[7]
* See section Section 12.5, “How do I report a bug in Debian?”
for notes on reporting bugs.
12.2.2. Web forum
Debian User Forums (http://forums.debian.net/) provides web
forums on which you can submit questions about Debian and have
them answered by other users. (It is not an officially part of
the Debian project.)
12.2.3. Wiki
Solutions to common problems, howtos, guides, tips and other
documentation can be found at the constantly changing Debian Wiki
(https://wiki.debian.org/) .
12.2.4. Maintainers
Users can address questions to individual package maintainers
using e-mail. To reach a maintainer of a package called xyz, send
e-mail to xyz@packages.debian.org.
12.2.5. Usenet newsgroups
Users should post non-Debian-specific questions to one of the
Linux USENET groups, which are named comp.os.linux.* or linux.*.
There are several lists of Linux Usenet newsgroups and other
related resources on the WWW, e.g. on the Linux Online (https://
www.linux.org/docs/usenet.html) and LinuxJournal (http://
www.linuxjournal.com/helpdesk.php) sites.
12.3. Is there a quick way to search for information on Debian GNU/
Linux?
There is a variety of search engines that serve documentation
related to Debian:
* Debian WWW search site (https://search.debian.org/) .
* Google Groups (https://groups.google.com/) : a search engine
for newsgroups.
For example, to find out what experiences people have had
with finding drivers for NVIDIA graphic cards under Debian,
try searching the phrase NVIDIA Linux driver. This will show
you all the posts that contain these strings, i.e. those
where people discussed these topics. If you add Debian to
those search strings, you'll also get the posts specifically
related to Debian.
* Any of the common web spidering engines, such as DuckDuckGo
(https://duckduckgo.com/) or Google (https://www.google.com/)
, as long as you use the right search terms.
For example, searching on the string "evince" gives a more
detailed explanation of this package than the brief
description field in its control file.
12.4. Are there logs of known bugs?
Reports on unsolved (and closed) issues are publicly available:
Debian promissed to do so by stating "We will not hide problems"
in the Debian Social Contract (https://www.debian.org/
social_contract) .
The Debian GNU/Linux distribution has a bug tracking system (BTS)
which files details of bugs reported by users and developers.
Each bug is given a number, and is kept on file. Once it has been
dealt with, it is marked as such.
Copies of this information are available at https://
www.debian.org/Bugs/ (https://www.debian.org/Bugs/) .
A mail server provides access to the bug tracking system database
via e-mail. In order to get the instructions, send an e-mail to
request@bugs.debian.org with "help" in the body.
12.5. How do I report a bug in Debian?
If you have found a bug in Debian, please read the instructions
for reporting a bug in Debian. These instructions can be obtained
in one of several ways:
* From the WWW. A copy of the instructions is shown at https://
www.debian.org/Bugs/Reporting (https://www.debian.org/Bugs/
Reporting) .
* On any Debian system with the doc-debian package installed.
The instructions are in the file /usr/share/doc/debian/
bug-reporting.txt.
You can use the package reportbug that will guide you through the
reporting process and mail the message to the proper address,
with some extra details about your system added automatically. It
will also show you a list of bugs already reported to the package
you are reporting against in case your bug has been reported
previously, so that you can add additional information to the
existing bug report.
Expect to get an automatic acknowledgement of your bug report. It
will also be automatically given a bug tracking number, entered
into the bug log and forwarded to the debian-bugs-dist mailing
list.
---------------------------------------------------------------------
^[7] Use the debian-list-subject-REQUEST@lists.debian.org address
for that.
Chapter 13. Contributing to the Debian Project
Donations (https://www.debian.org/donations) of time (to develop
new packages, maintain existing packages, or provide user
support), resources (to mirror the package and WWW archives), and
money (to pay for new testbeds as well as hardware for the
archives) can help the project. See also How can you help Debian?
(https://www.debian.org/intro/help) .
13.1. How can I become a Debian member/Debian developer?
The development of Debian is open to all, and new users with the
right skills and/or the willingness to learn are needed to
maintain existing packages which have been "orphaned" by their
previous maintainers, to develop new packages, to write
documentation, to do translation work, to help with the Debian
website, to provide user support, etc.
The description of becoming a Debian member can be found at the
New Member's Corner (https://www.debian.org/devel/join/newmaint)
at the Debian web site.
13.2. How can I contribute resources to the Debian project?
Since the project aims to make a substantial body of software
rapidly and easily accessible throughout the globe, mirrors are
needed. It is desirable but not absolutely necessary to mirror
all of the archive. Please visit the Debian mirror size (https://
www.debian.org/mirror/size) page for information on the disk
space requirements.
Most of the mirroring is accomplished entirely automatically by
scripts, without any interaction. However, the occasional glitch
or system change occurs which requires human intervention.
If you have a high-speed connection to the Internet, the
resources to mirror all or part of the distribution, and are
willing to take the time (or find someone) who can provide
regular maintenance of the system, then please contact <
debian-admin@lists.debian.org>.
13.3. How can I contribute financially to the Debian project?
Donations from sponsors allow Debian to have machines, as well as
other hardware, organise conferences and development sprints,
amongst other things. For more information please visit Debian
Donations (https://www.debian.org/donations) . The page also
lists the different methods that can be used to donate.
One can make individual donations to organizations that are
critical to the development of the Debian project. The main
organization is Software in the Public Interest, incorporated in
the United States, but there are others.
13.3.1. Software in the Public Interest
Software in the Public Interest (SPI) is an IRS 501(c)(3)
non-profit organization based in the United States. The purpose
of the organization is to develop and distribute free software.
It encourages programmers to use the GNU General Public License
or other licenses that allow free redistribution and use of
software, and hardware developers to distribute documentation
that will allow device drivers to be written for their product.
SPI acts as a fiscal sponsor to many free and open source
projects. The Debian project has been an associate project since
the organization's creation.
SPI can be reached at: https://www.spi-inc.org/ (https://
www.spi-inc.org/) .
13.3.2. Other organizations
There are a number of organizations created in different
countries that hold assets in trust for Debian. The donations
page (https://www.debian.org/donations) lists the trusted
organizations individuals can donate to. At the time of this
writing there are two of them: the Debian France Association
(https://france.debian.net/) (in France), and debian.ch (https://
debian.ch/) (Switzerland and the Principality of Liechtenstein).
Additional affiliate organizations in other countries are listed
in Organizations (https://wiki.debian.org/Teams/Auditor/
Organizations) page in the Debian Wiki.
Chapter 14. Redistributing Debian GNU/Linux in a commercial product
14.1. Can I make and sell Debian CDs?
Go ahead. You do not need permission to distribute anything we
have released, so that you can master your CD as soon as the
beta-test ends. You do not have to pay us anything. Of course,
all CD manufacturers must honor the licenses of the programs in
Debian. For example, many of the programs are licensed under the
GPL, which requires you to distribute their source code.
Also, we will publish a list of CD manufacturers who donate
money, software, and time to the Debian project, and we will
encourage users to buy from manufacturers who donate, so it is
good advertising to make donations.
14.2. Can Debian be packaged with non-free software?
Yes. While all the main components of Debian are free software,
we provide a non-free directory for programs that are not freely
redistributable.
CD manufacturers may be able to distribute the programs we have
placed in that directory, depending on the license terms or their
private arrangements with the authors of those software packages.
CD manufacturers can also distribute the non-free software they
get from other sources on the same CD. This is nothing new: free
and commercial software are distributed on the same CD by many
manufacturers now. Of course we still encourage software authors
to release the programs they write as free software.
14.3. I am making a special Linux distribution for a "vertical
market". Can I use Debian GNU/Linux for the guts of a Linux system
and add my own applications on top of it?
Yes. Debian-derived distributions are being created both in close
cooperation with the Debian project itself and by external
parties. One can use the Debian Pure Blends (https://
www.debian.org/blends/) framework to work together with Debian;
DebianEdu/Skolelinux (https://wiki.debian.org/DebianEdu/) is one
such project.
There are several other Debian-derived distributions already on
the market, such as grml, LMDE (Linux Mint Debian Edition),
Knoppix and Ubuntu, that are targeted at a different kind of
audience than the original Debian GNU/Linux is, but use most of
our components in their product.
Debian also provides a mechanism to allow developers and system
administrators to install local versions of selected files in
such a way that they will not be overwritten when other packages
are upgraded. This is discussed further in the question on
Section 11.9, “How do I override a file installed by a package,
so that a different version can be used instead?”.
14.4. Can I put my commercial program in a Debian "package" so that
it installs effortlessly on any Debian system?
Go right ahead. The package tool is free software; the packages
may or may not be free software, it can install them all.
Chapter 15. Changes expected in the next major release of Debian
With each new release, the Debian project tries to focus on a set
of topics. These are known as "Release Goals" and they are all
described in https://wiki.debian.org/ReleaseGoals/ (https://
wiki.debian.org/ReleaseGoals/) . Please note that the following
sections might not be fully up-to-date, please refer to the Wiki
for more information and the up-to-date status of these goals.
15.1. Hardening the system
It is a goal for the Debian project to ensure that any system
installed is hardened and secure against attacks. There are
several ways to achieve this, which include:
* Improve programs' security by compiling them with Security
Hardening Build Flags (https://wiki.debian.org/ReleaseGoals/
SecurityHardeningBuildFlags) in order to enable various
protections against known security issues,
* Improve the default system configuration to make it less
vulnerable to attacks (both local or remote),
* Enable security features delivered by new versions of the
kernel.
All of these are done in an ongoing basis. For the first item, a
set of security hardening build flags that try to prevent known
attacks such as stack smashing, predictable locations of values
in memory, etc. is used. The target is to cover at least all
packages that are part of the basic installation as well as
packages that had to be updated through a Security Advisory since
2006. As of this writing, around 400 packages have been modified
since this effort was first started. All the issues are tracked
in the BTS (https://bugs.debian.org/cgi-bin/pkgreport.cgi?tag=
goal-hardening;users=hardening-discuss@lists.alioth.debian.org) .
15.2. Extended support for non-English users
Debian already has very good support for non-English users, see
Section 5.9, “How does Debian support non-English languages?”.
We hope to find people who will provide support for even more
languages, and translate programs and documents. Many programs
and Debian-specific documents already support
internationalization, so we need message catalogs translators.
However, still some programs remain to be properly
internationalized.
The GNU Translation Project ftp://ftp.gnu.org/pub/gnu/ABOUT-NLS
(ftp://ftp.gnu.org/pub/gnu/ABOUT-NLS) works on internationalizing
the GNU programs and different projects, such as the Desktop
environments GNOME or KDE have their own translation teams. The
goal of Debian is not to replace or to repeat the work done by
these projects, indeed, Debian benefits from the work done by
translators in these projects. However, there are still many
programs which are not in the scope of those projects and which
are translated within Debian.
Previous Debian releases have focused in topics such as:
* I18n support in all debconf-using packages: Packages using
the Debian configuration management must allow for
translation of all messages displayed to the user during
package configuration.
* I18n support for package descriptions: Update package
management frontends to use the translated descriptions of
packages.
* UTF-8 debian/changelog and debian/control. This way, e.g.
names of people from asian countries can get typeset the
right way in changelogs.
* I18n support in the Debian Installer including full support
for some languages that require the use of the graphical
interface.
15.3. Improvements in the Debian Installer
Lots of work has been done on the Debian Installer, resulting in
major improvements. We'll mention just two of them here.
Starting the installer from Microsoft Windows: It is now possible
to start the installer directly from Microsoft Windows without
the need to change BIOS settings. Upon insertion of a CD-ROM,
DVD-ROM or USB stick, an autorun program will be started,
offering a step-by-step process to start the Debian Installer.
15.4. More architectures
Complete Debian system on other architectures. Notice that even
though some architectures are dropped for a given release, there
still might be a way to install and upgrade using the latest sid.
15.5. More kernels
In addition to Debian GNU/Hurd, Debian is being ported also to
BSD kernels, namely to FreeBSD (https://www.debian.org/ports/
kfreebsd-gnu/) . This port runs on both AMD64 ("kfreebsd-amd64")
and traditional Intel ("kfreebsd-i386").
Chapter 16. General information about the FAQ
16.1. Authors
The first edition of this FAQ was made and maintained by J.H.M.
Dassen (Ray) and Chuck Stickelman. Authors of the rewritten
Debian GNU/Linux FAQ are Susan G. Kleinmann and Sven Rudolph.
After them, the FAQ was maintained by Santiago Vila and, later,
by Josip Rodin. The current maintainer is Javier
Fernandez-Sanguino.
Parts of the information came from:
* The Debian-1.1 release announcement, by Bruce Perens (https:/
/perens.com/) ,
* the Linux FAQ, by Ian Jackson (https://
www.chiark.greenend.org.uk/~ijackson/) ,
* Debian Mailing Lists Archives (https://lists.debian.org/) ,
* the dpkg programmers' manual and the Debian Policy manual
(see Section 12.1, “What other documentation exists on and
for a Debian system?”),
* many developers, volunteers, and beta testers,
* the flaky memories of its authors. :-)
* and the Choosing a Debian distribution FAQ (http://
KamarajuKusumanchi.github.io/choosing_debian_distribution/
choosing_debian_distribution.html) , which Kamaraju
Kusumanchi graciously released under the GPL, so it could be
included as a new chapter (see Chapter 3, Choosing a Debian
distribution).
The authors would like to thank all those who helped make this
document possible.
All warranties are disclaimed. All trademarks are property of
their respective trademark owners.
16.2. Feedback
Comments and additions to this document are always welcome.
Please send e-mail to <doc-debian@packages.debian.org>, or submit
a wishlist bug report against the debian-faq (https://
bugs.debian.org/debian-faq) package.
16.3. Availability
The latest version of this document can be viewed on the Debian
WWW pages at https://www.debian.org/doc/FAQ/ (https://
www.debian.org/doc/FAQ/) .
It is also available for download in plain text, HTML, and PDF
formats at https://www.debian.org/doc/user-manuals#faq (https://
www.debian.org/doc/user-manuals#faq) . Also, there are several
translations there.
This document is available in the debian-faq package.
Translations are available in debian-faq-de, debian-faq-fr and
other packages.
The original XML files used to create this document are also
available in debian-faq's source package, or in GIT at:
git@salsa.debian.org:ddp-team/debian-faq.git and https://
salsa.debian.org/ddp-team/debian-faq (https://salsa.debian.org/
ddp-team/debian-faq) .
16.4. Document format
This document was written using the DocBook XML DTD. This system
enables us to create files in a variety of formats from one
source, e.g. this document can be viewed as HTML, plain text, TeX
DVI, PostScript, PDF, or GNU info.
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