The Debian GNU/Linux FAQ
Susan G. Kleinmann (sgk@debian.org),
Sven Rudolph (sr1@inf.tu-dresden.de), and
Joost Witteveen (joostje@debian.org)
22 August 1996
This document answers questions frequently asked about the Debian dis-
tribution of GNU/Linux. (See section ``copyrights'' for the Copyright
details.)
1. Meta-questions
1.1.
In what format is this document written?
This document was written using Linuxdoc-SGML. The Linuxdoc-SGML
system can be used to create files in a variety of other formats,
e.g., GNU info, HTML, LaTeX, TeX .dvi format, and Postscript (TM)
files.
1.2.
Where do I get the latest version of this document?
The latest version of this document can be viewed in HTML format at
the Debian home page <http://www.debian.org/FAQ>.
It is also available in plain text format at any of the Debian mirrors
in the directory doc/FAQ as debian-faq.txt.
The original SGML file used to create this document is available as
part of the Debian package called doc-debian_VVV-RRR.deb, where VVV is
the latest version number and RRR is the latest revision number. This
package is normally stored in the directory Debian-1.1/binary-all/doc.
The linuxdoc-sgml package contains tools to transform this document
into one or more other formats, as required by the user: GNU info
files, HTML, LaTex, TeX .dvi format, and Postscript.
1.3. Where do I send questions, corrections, etc. about this docu-
ment?
Comments on this document are welcome. Please send Email to debian-
faq@debian.org.
1.4. (How) Can I redistribute this file?
This document is copyright 1996 by ``Software in the Public
Interest''.
Permission is granted to make and distribute verbatim copies of this
document provided the copyright notice and this permission notice are
preserved on all copies.
Permission is granted to copy and distribute modified versions of this
document under the conditions for verbatim copying, provided also that
the section entitled ``GNU General Public License'' is included
exactly as in the original, and provided that the entire resulting
derived work is distributed under the terms of a permission notice
identical to this one.
Permission is granted to copy and distribute translations of this
document into another language, under the above conditions for
modified versions, except that the sections entitled ``GNU General
Public License'' and this permission notice may be included in
translations approved by the Free Software Foundation instead of in
the original English.
1.5. What information resources were used to obtain the questions and
answers presented here?
This FAQ previously was maintained by J.H.M. Dassen
(jdassen@wi.LeidenUniv.nl) and Chuck Stickelman (stick@richnet.net).
Parts of the information came from
o The Debian-1.1 release annoucement
<http://www.debian.org/1.1/release.html> by Bruce Perens.
o The Linux FAQ <http://www.cl.cam.ac.uk/users/iwj10/linux-faq/> by
Ian Jackson <http://www.cl.cam.ac.uk/users/iwj10/ijackson.html>.
o The Debian Mailing List Archives <http://www.debian.org/Lists-
Archives/>
o The dpkg programmers' manual, which is incorporated into recent
versions of the Debian package known as dpkg.
o The Debian policy manual, which is incorporated into recent
versions of the Debian package known as dpkg.
o The many developers, volunteers, and beta testers.
o The flaky memories of its authors.
The authors would like to thank all those who helped make this
document possible.
2. Definitions and Overview
2.1. What is Debian GNU/Linux?
Debian GNU/Linux is a particular distribution of the Linux operating
system, and numerous packages that run on it. In principle, users
could obtain the Linux kernel from the 'net or 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. Debian was
created by Ian Murdock in 1993, initially under the sponsorship of the
Free Software Foundations's GNU project. Today, Debian's developers
think of it as a direct descendent of the GNU project.
Debian GNU/Linux is
o full featured: The Debian distribution includes nearly 500
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 the
Debian distribution at any of the Debian mirror sites.
o 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 the Debian
distribution are free to redistribute, usually under terms
specified by the GNU General Public License. The Debian FTP
archives also carry approximately 50 software packages (in the non-
free and contrib directories at the FTP archives), which are
distributable under specific terms included with each package.
o dynamic: With about 100 volunteers constantly contributing new and
improved code, the Debian distribution is evolving rapidly. New
releases are made about every three months, and the FTP archives
are updated daily.
Though Debian itself is free software, it is a base upon which value-
added GNU/Linux distributions can be built. By providing a reliable,
full-featured base system, Debian provides GNU/Linux users with
increased compatibility, and allows GNU/Linux distribution creators to
eliminate duplication-of-effort and focus on the things that make
their distribution special.
2.2. Ok, now I know what Debian is...what's Linux!?
In short, Linux is the kernel of a Unix-like operating system. It was
originally designed for 386/486/Pentium PCs; now, ports to other
systems, including multi-processor systems, are under development.
Linux is written by Linus Torvalds and many computer scientists around
the world.
Besides its kernel, a "Linux" system usually has
o a file system that follows the Linux Filesystem Hierarchy Standard
<ftp://tsx-11.mit.edu/pub/linux/docs/linux-
standards/private/fsstnd/draft5.tar.gz>.
o 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 filesystem, the GNU and FSF
utilities, and the other utilities are designed to achieve compliance
with the POSIX (IEEE 1003.1) standard. (The authors would very much
like to give you a pointer to an on-line document that described that
standard, but the IEEE is another one of those organizations that gets
away with declaring standards and then requiring that people PAY to
find out what they are. This makes about as much sense as having to
find out the significance of various colored lights on traffic
signals.) At least one distribution (Linux-FT by LaserMoon
<http://www.lasermoon.co.uk/linux-ft/linux-ft.html>) has already been
certified POSIX compliant.
For more information about Linux, see Michael Johnson's INFO-SHEET
<ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/INFO-SHEET> and META-FAQ
<ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/META-FAQ>.
2.3. What's the difference between Debian and other Linux distribu-
tions?
Three key features distinguish Debian from other distributions of
GNU/Linux:
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 GNU/Linux distributions available today have some
kind of package maintenance system; the ``Debian package
maintenance system'' is unique and particularly robust.
Open development:
Whereas other GNU/Linux distributions are developed by
individuals, small, closed groups, or commercial vendors, Debian
is the only GNU/Linux distribution that is being developed
cooperatively by many individuals through the Internet, in the
same spirit as GNU/Linux and other Free Software. More than 100
volunteer package maintainers are working on over 500 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''.
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 post bugs in a formal style, which are quickly
accessible by both FTP and WWW archives to developers and users
alike. See additional information in this FAQ on the management
of the ``Bug Log''.
2.4. 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 FSF and in particular by Richard Stallman. FSF's
powerful system development tools, utilities, and applications are
also a key part of the Debian system.
At one time, there was a formal relationship between the Debian
project and the FSF, in that the FSF employed Ian Murdock for a year
while he was project leader. The project was then called the "Debian
GNU/Linux" system. Now, however, the FSF will pursue its long-
standing objective of developing a new operating system based on HURD
( <http://www.cs.pdx.edu/~trent/gnu/hurd/index.html>), rather than the
Linux kernel, while the Debian project will take exclusive control
over its own technical direction.
The Debian project supports the goals of FSF and we like to think of
Debian as "Son of GNU". We think the FSF considered Debian as a first
step toward the completed HURD system, and still encourage FSF to
derive from Debian. Though the Debian project is no longer sponsored
by the FSF, both groups have decided that this should not keep us from
working together, and that we should be partners. We all look forward
to more support for Linux in GNU software, and more support for FSF's
goals in Linux software.
2.5.
How does one pronounce Debian and what does this word mean?
The project name is pronounced Deb'-ian, with a short e, 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'-an.)
3. Hardware Requirements
3.1.
On what architectures/systems does Debian GNU/Linux run?
The Debian Linux distribution 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://www.cl.cam.ac.uk/users/iwj10/linux-faq/> for details.
The current Debian Linux distribution contains a complete, binary
distribution for Intel-based PC's, including 80386, 80486, Pentium,
and Pentium Pro's. The development of binary distributions of Debian
1.1 for 68k processors is currently underway, and ports to Alpha,
Sparc, and MIPS processors are expected to follow.
3.2.
What hardware is assumed by the stock Debian GNU/Linux boot disks?
The configuration file used to build the standard distribution Debian
GNU/Linux kernel assumes an 80386 CPU, and includes support for PCMCIA
cards, most SCSI cards for which there exist Linux drivers (with the
notable exception of the NCR53c810), and most Ethernet cards for which
there exist Linux drivers.
Linux kernels suited to a variety of special platforms are included in
the directory buzz-fixed/disks-i386/special-kernels at any Debian FTP
archive site, along with their configuration files. Briefly, these
platforms include:
o Special Kernel 0: Small kernel (Standard Distribution, but without
drivers for PCMCIA, QLlogic SCSI host adapters, Ethernet adapters,
and Sound cards)
o Special Kernel 1: All Adaptec SCSI + AdvanSys + Always + AM5379c974
+ BusLogic
o Special Kernel 2: DTC + eata_dma (DPT), eata_pio (OLD DPT) + Future
Domain
o Special Kernel 3: NCR5380/53c400 + NCR53c406a + NCR53c7/8xx
o Special Kernel 4: Iomega Parallel + PAS16 + Qlogic + Seagate +
Trantor + UltraStor
o Special Kernel 5: Special NCR53c400 only Kernel
o Special Kernel 6: Special NCR53C8xx only Kernel
3.3.
What amount of disk space is recommended?
A generous installation, sufficient to accommodate a few users, X
windows software, and several large applications, might require disk
partitions at least as large as:
o 50 MBytes for the root directory (/)
o 500 MBytes for /usr
o 50 MBytes for swap space
o 50 MBytes for each home directories
o 100 MBytes for /tmp
o 100 MBytes for /var
The optimum disk space allocated for swap depends critically on the
way the system will be used. Many people just choose to set aside
twice as much disk space as they have RAM space. Systems with large
RAM may not need so much swap space, especially if there are only a
few users. The installation process supports systems with no swap
space.
3.3.1. But how much RAM and disk space are absolutely essential?
These minimal requirements are sufficient for a system without X
windows and only 1 or 2 users:
o 15 MBytes of disk space for the base system; this provides a
minimally-functioning Unix system, but includes no application
programs and no network support.
o 80 MBytes of disk space for a standard system running applications
on the console (i.e., without an X11 interface).
o 120 MBytes of disk space for a standard system running applications
with an X11 window system.
o 300 MBytes and more for all all the optional programs (You probably
don't need all of these prorams.)
Debian Linux can be installed on systems with only 4 MBytes of RAM.
The latest installation disks are especially organized to provide an
easy installation path for machines with small memories. Some users
report success at using Debian Linux to convert PC's having limited
RAM (and disk space) into X terminals. An 80386-based system with
only 4 MBytes of RAM and 40 MBytes disk space has been used to run
Debian Linux in this way; i.e., both networking and basic X11 server
functions operated satisfactorily. This mode of operation even works
if 1 MByte of the RAM is used as a ramdisk when the machine is booted,
implying that only 3 Mbytes of RAM is absolutely essential for using
Debian Linux on a PC in order to use it as an X server. This mode of
operation requires a swap partition; without it, the system won't even
go into multi-user mode.
3.4.
How should I partition my drive?
Partitioning a drive has the disadvantage that drive space can be used
much less flexibly than an unpartitioned drive. Most users find,
however, that this disadvantage is more than offset by the fact that
damage to a filesystem on a partitioned disk is usually limited to a
single partition. Furthermore, backups of a partitioned hard disk can
be more easily managed because the files that change most frequently
are likely to be localized to a single partition.
A user with a 1.6 GByte drive has concluded after a survey of Debian
users that it's reasonable to design a partitioning scheme that
closely follows the Linux standard File System Structure
<http://www.eg.bucknell.edu/~quinlan/fsstnd/>. For his 1.6 GByte
disk, he chose these partitions:
o 30 MBytes for the root directory (/)
o 450 MBytes for /usr
o 50 MBytes for swap space
o 1000 MBytes for home directories (some of this could be used for
/usr/local)
o 0 MBytes for /tmp; make /tmp a symbolic link to /var/tmp
o 40 MBytes for /var
Note that for best performance one should definitely place the swap
file in its own partition. Ideally, this partition would reside on a
drive controlled by a different controller than that which contains
the user partition. (But hard evidence that this approach really
yields better performance is lacking at present.)
3.5.
Are very large disks supported?
There is an upper limit on the size of the disk partition that's used
for booting. This limit applies to all operating systems, not just
Linux, and not just Debian Linux. Basically, the BIOS's typically
available on PC's cannot access disk partitions larger than 1024
cylinders or tracks. Thus, any operating system used on a PC cannot
be booted from a disk partition larger than 1 GByte. It's worth
emphasizing that this restriction only applies to the partition from
which Linux is booted. Other partitions can be larger. One solution
to this limitation is to place the directory /boot/ in its own (very
small) partition, entirely within the first 1024 blocks of the disk.
Recent versions of the Linux kernel include the the Multi-Device disk
driver ('md'), which provides striping support (sometimes called RAID
0) in software as well as a linear mode of joining 2 or more disks
into a single logical device that can be formatted as a single file
system.
3.6.
(How) does Debian provide PCMCIA support?
The version of the kernel distributed with the Debian installation
disks includes support for PCMCIA cards. That is, its .config file
includes the line: CONFIG_BLK_DEV_IDE_PCMCIA=y. This configuration
just supports modification of the IDE driver in the kernel to support
IDE disks that are PCMCIA cards.
Utilities that actually provide pcmcia card services have been
developed by David Hinds. These utilities are provided in the Debian
distribution by the package pcmcia-cs-KKK_VVV-RRR.i386.deb, where the
components 'VVV' and 'RRR' follow the usual conventions on ``Debian
package names'', and the component 'KKK' refers to the kernel version
for which the pcmcia-cs package was built.
4. Compatibility issues
4.1.
How compatible is Debian with other distributions of Linux?
Debian developers communicate with other GNU/Linux distribution
creators in an effort to maintain binary compatibility across Linux
distributions. Most commercial GNU/Linux products run as well under
Debian as they do on the system upon which they were built.
Debian GNU/Linux adheres strictly to the Linux File System Structure
<http://www.eg.bucknell.edu/~quinlan/fsstnd/> (now known as the FHS).
However, there is room for interpretation in some of the rules within
this standard, so there may be differences between a Debian system and
other Linux systems.
4.2. Can I use RedHat packages (".rpm" files) on my Debian Linux sys-
tem?
Can I use Debian packages (".deb" files) on my RedHat/Slackware/...
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's
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
RedHat or Slackware package on a host that's based on Debian
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
File System Standard.
You probably don't 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 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, removal individually.
4.3.
Is Debian able to run my old "a.out" programs?
o To execute a program whose binary is in a.out (i.e., QMAGIC or
ZMACI) format,
o make sure your kernel has a.out support built into it, either
directly (CONFIG_BINFMT_AOUT=y) or as a module
(CONFIG_BINFMT_AOUT=m). (Debian is distributed with a kernel with
support for a.out binaries built in directly.)
If your kernel supports a.out binaries by a module, then be sure
that the binfmt_aout module is loaded. You can do this at boot
time by entering the line binfmt_aout into the file /etc/modules.
You can do it from the command line by executing the command insmod
DIRNAME/binfmt_aout.o where DIRNAME is the name of the directory
where the modules that have been built for the version of the
kernel now running are stored. On a system with the 2.0.0 version
of the kernel, DIRNAME is likely to be /lib/modules/2.0.0/fs/.
o install the package libc4.
o To compile programs in the a.out binary format,
o install the Debian a.out developer's packages, which are
o libc4-dev
o aout-binutils
o aout-librl
o aout-gcc
o place the a.out tools ahead of the ELF tools in your path. That
is, execute the command export PATH=/usr/i486-linuxaout/bin:$PATH
(This isn't essential, just advantageous.) If you're only going to
do this once, you could execute: PATH=/usr/i486-linuxaout/bin:$PATH
make [target].
o To execute a.out X clients, install the xcompat package.
If you have a commercial application in a.out format, now would be a
good time to ask them to send you an ELF upgrade.
4.4.
How should I install a non-Debian package?
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/foo, 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 doc-debian package; or see the
on-line guide
<http://www.debian.org/Documentation/Debian/guidelines_toc.html> to
the package development guidelines.
4.5.
Why can't I compile programs that require libtermcap?
Debian uses the terminfo database and the ncurses library of terminal
interface routes, rather than the termcap database and the termcap
library. Users who are compiling programs that require some knowledge
of the terminal interface should replace references to libtermcap with
references to libncurses.
To support binaries that have already been linked with the termcap
library, and for which you don't have the source, Debian provides a
package called termcap-compat. This provides both libtermcap.so.2 and
/etc/termcap. Install this package if the program fails to run with
the error message "can't load library 'libtermcap.so.2'", or complains
about a missing /etc/termcap file.
4.6.
Why can't I install AccelX? (termcap again)
AccelX uses the termcap library for installation. Debian uses the
terminfo database and ncurses library instead. To run programs which
use the termcap library, install the package termcap-compat; it can be
found in the misc section in the Debian archives.
4.7. Why do I get "Can't find libX11.so.6" errors when I try to run
foo?
Programs that require the libX11.so.6 library are in a.out format. To
execute them, you need to install the xcompat package.
4.8. Can I install and compile a kernel without some Debian-specific
tweaking?
Yes. But you have to understand the Debian policy with respect to
headers.
The Debian C libraries are built with the most recent stable releases
of the gcc headers. For example, the Debian-1.1 release uses version
5.2.18 of the headers. This practice contrasts with the Linux kernel
source packages distributed at all Linux FTP archive sites, which uses
even more recent versions of the headers. The kernel headers
distributed with the kernel source are located in
/usr/include/linux/include.
If you need to compile a program with kernel headers that are newer
than those provided by libc5-dev, then you must add
-I/usr/src/linux/include to your command line when compiling. This
came up at one point, for example, with the packaging of the
automounter daemon (amd). When new kernels changed some internals
dealing with NFS, amd needed to know about them. This required the
inclusion of the latest kernel headers.
5. Software Available in the Debian system
5.1. What types of applications and development software are avail-
able for Debian GNU/Linux?
Like most Linux distributions, Debian GNU/Linux provides
o the major GNU applications for software development, file
manipulation, and text processing, including gcc, libc, g++, make,
texinfo, gnuplot, the Bash shell and numerous upgraded Unix
utilities.
o Perl and its libraries
o TeX, LaTeX, and dvips
o the X Window system, which provides a networked graphical user
interface for Linux, and numerous X applications,
o a full suite of other networking applications, including WWW
servers, browsers, and development tools.
Nearly 500 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. Another 50 software suites are available as Debian
packages, but are not formally part of the Debian distribution due
to license restrictions.
5.2. Who wrote all that software?
o Authors whose software is included in the Debian Linux system are
credited in files listed in /usr/doc/copyright.
o Maintainers who package this software for the Debian Linux system
are listed in the ``Debian control file'' that comes with each
package.
5.3. How can I get a current list of programs that have been packaged
for the Debian project?
A complete list is available from any of the Debian mirrors.
The file indices/Packages-Master-i386.gz provides a list, including
short descriptions, of all packages that are available for computers
with 80386 (or more advanced) chips. The file indices/Packages-
Master-m68k.gz provides a similar list of packages that are available
for computers with Motorola 68xxx CPUs.
The WWW interface to the Debian packages <http://www.debian.org/FTP/>
conveniently summarizes the packages in each of about twenty
"sections" of the Debian archive, as well as the 10 most recently
uploaded packages.
5.4. What's missing from Debian GNU/Linux?
A list of packages which are most urgently needed for the Debian
distribution is maintained by Sven Rudolph. For more details, see the
section ``on contributing to the Debian project''.
5.5. Where is 'which'?
This is a historical question, no longer relevant, but is included
with this FAQ because it may still hold the record as the single most
frequently asked question on the Debian mailing lists.
The functionality of the Berkeley utility which is provided in the
Bash shell by the built-in command type. To learn the path name for
an executable file "foo", use the command type foo. To learn all the
paths where "foo" can be found, use type -a foo.
To accommodate users' lack of familiarity with this (in this writer's
opinion, obscure) feature of Bash, the Debian maintainers have built a
package called debianutils, which includes a Bash script called which.
This script includes only these lines:
#!/bin/bash
for i in $*; do
type -all -path $i | head -1
done
The debianutils package is normally stored in the base section of the
FTP archive, and is therefore part of the initial installation of
every Debian system.
5.6. (How) Does Debian support Java?
The Java Development Kit from Sun is currently available as a Debian
package (jdk_VVV-RRR_i386.deb). The JDK will allow you to run Java
programs and applets, and write your own. If your kernel is properly
configured (see below), the JDK will allow you to run Java programs
just like other executables. The JDK package also includes a number
of demo programs.
Debian's kernel is configured with Java support built in as a module
(i.e., CONFIG_BINFMT_JAVA=m). Users who wish to build their own
``custom kernel'' can of course omit this if they choose. Once module
support is available in the kernel, you need to make sure the module
is loaded. You can do it at boot time by inserting the line
binfmt_java in the file /etc/modules. Alternatively, you can install
the module from the command line by executing the command insmod
DIRNAME/binfmt_java.o where DIRNAME is the name of the directory where
the modules that have been built for the version of the kernel now
running are stored. On a system with the 2.0.0 version of the kernel,
DIRNAME is likely to be /lib/modules/2.0.0/fs/. You can check that a
module is loaded using the command lsmod.
Running a Java applet requires a browser with the capability to
recognize and execute them. The Netscape browser that can be
installed as a Debian package will run Java applets. (The Netscape
source code is not publicly available. The Debian netscape package
provides a wrapper which aids the installation and management of
Netscape on a Debian system. This is actually a good example of the
integration of commercial packages with the Debian system.)
A final note of mixed blessings: Sun's licensing policies on the JDK
are becoming more restricted with time, so this package may not be
available as part of the Debian distribution soon. It is possible
that it may be available in the same way that Netscape is available
for Debian Linux. Better news is that a number of ports are currently
being developed with may provide attractive publicly-available
alternatives.
5.7. What are all those directories (buzz/non-free/contrib/project)
at the Debian FTP archives?
The software that's been packaged for Debian GNU/Linux is available in
one of several directory trees on each Debian mirror site.
5.7.1. Top Level Directories
The Major Package Trees
o Debian-1.1, a.k.a. "buzz": This directory contains the packages
which formally constitute the most recent release of the Debian
Linux system. The contents of this directory do not change.
o Debian-1.1-updates, a.k.a. "buzz-fixes": Updates to the current
release are in this directory.
o Debian-1.1.x, a.k.a. "stable" and "buzz-fixed": A copy of the
the current release with the updates applied. The minor number
is changed whenever new updates are added.
o "non-free": This directory contains packages whose distribution
is restricted in a way which 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 freeware. 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).
o "contrib": This directory contains packages which are freely
distributable, but do not meet the policy requirements for
distribution by the Debian project for some reason, e.g., the
packages have some unusual restriction on modification by other
users, or are only available in binary form. For such packages,
the project cannot given the user any means to assure that they
are free of Trojan horses, and cannot port them to other
architectures. Binary-only packages which are not freely
redistributable are placed in the non-free directory.
Supplementary directories:
o "tools": DOS utilities for creating boot disks, partitioning
your disk drive, compressing/decompressing files, and booting
Linux.
o "upgrades": Files needed for upgrading a debian-0.93 system
(based on a.out binary format files) to Debian-1.1 (based on ELF
binary files). Included are instructions for upgrading (either
"manually" using dpkg, or more automatically, using dselect),
along with a copy of the particular version of the package
management tool, dpkg that must be used in a.out systems to
start the upgrade, and a list of files that will be needed in
order to do the upgrade.
o "doc": Documentation, instructions on how to submit bug
reports.
o "debian-lists": Archives of the Debian mailing lists.
Of particular interest to developers:
o "project/experimental": This directory contains packages and
tools which are being developed specifically for the Debian
project, and are still in the testing stage. Users are welcome
to use and test these packages, but warned about their state of
readiness.
o "rex", a.k.a. "unstable", a.k.a. "development": A snapshot of
the current development system. Users are welcome to use and
test these packages, but are warned about their state of
readiness.
o "private/project/Incoming": Packages that have been uploaded by
developers, and which are awaiting placement in the directory
hierarchy by the distribution maintainer.
o "debian-bugs/": Archive of the bug reports.
o "indices": Various lists, including the Packages-Master file.
5.7.2. Sub-directories
Within each of the major directory trees (Debian-1.1, non-free, and
contrib, but not project/experimental), which is too small to
subdivide), the binary packages reside in sub-directories whose names
indicate the chip architecture for which they were compiled:
o binary, which is normally a link to binary-i386.
o binary-all, for packages which are architecture-independent. These
include, for example, Perl scripts.
o binary-i386, for packages which execute on 80x86 machines.
o binary-m68k, for packages which execute on machines based on one of
the Motorola 680x0 processors. Currently this is done mainly for
Atari and Amiga computers, and also for some VME based industry
standard boards. There is no port of Linux to the old m68k based
Macintosh's, since Apple will not supply the needed hardware
information.
o binary-sparc, for packages which execute on Sun Sparcstations.
o binary-alpha, for packages which execute on DEC Alpha machines.
5.8. Is source code included with the system?
Source code is included for everything in the Debian system. Most of
the license terms of 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.
Source code may or may not be available for packages in the "contrib"
"non-free" directories, which are not formally part of the Debian
system.
5.9. How can I check that I'm using a Debian system?
Check for the existence of the file /var/lib/dpkg/status. This
contains a stanza reporting the status of each of the installed Debian
packages on a system.
5.10. How can I tell what "version" of the Debian system I am using?
There is a file, /etc/debian_version, which contains a single one-line
entry giving the version number of the release, as defined by the
package base.
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 -l foo.
(With no arguments, this command prints out versions of all installed
packages.) For a more verbose description, use dpkg --status foo.
5.11. How does the Debian distribution support non-English languages?
o 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 keyboad he'll use.
o Support for German-languange manpages is provided through the
manpages-de package, and support for Spanish-language manpages is
provided through the manpages-es package. To access an NLS
manpage, the user must set LC_MESSAGES to the appropriate string.
In the case of the German-language manpages, LC_MESSAGES must be
set to 'de_DE'. The man program will then search for german
manpages under /usr/man/de_DE.
6. Basics of the Debian Package Management System
6.1. What is a Debian package?
Packages generally contain all of the files necessary to implement a
set of related commands or features. Packages come in two flavors:
o 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''; they are distinguished by having a '.deb' file extension.
o Source packages, which contain all of the files necessary to create
the comparable binary package. These packages are distributed as
gzip-compressed tar files, and therefore are distinguished by a
'.tar.gz' file extension.
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, Debian's package system will send an error message
that it also needs binutils, and will install gcc only if the user
agrees to install binutils first. (However, this facility can be
overridden by the insistent user.) More details are given ``below''
on package dependencies.
Debian's packaging tools can be used to:
o manipulate and manage packages or parts of packages,
o aid the user in the break-up of packages that must be transmitted
through a limited-size medium such as floppy disks,
o aid developers in the construction of package archives, and
o aid users in the installation of packages which reside on a remote
FTP site.
6.2. What is the format of a Debian 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.
Debian archive files can be parsed and manipulated by the utility ar.
The precise contents of Debian archive files changed since Debian
0.93. The new contents are understood by versions of the primary
package tool, dpkg, later than 0.93.76, and is described in the
"deb"(5) man page. The old format is described in "deb-old"(5).
An archive file contains at least these members (in this order):
o debian-binary: Contains one or more lines; currently it contains
only one line giving the version number (2.0) of the Debian package
format.
o control.tar.gz: A compressed (gzip'd) tar file which contains the
``Debian control files'' for this package. (Confusingly, one of
these files, and the only one which is required, is itself named
control.)
o data.tar.gz: A compressed (gzip'd) tar file which contains the
executables, libraries, documentation, etc., associated with this
package.
Additional members may be added. Detailed requirements for adding
them are given in the deb manual page.
6.3. Why are Debian package names so long?
The Debian package names conform to the following convention:
<foo>_<VersionNumber>-<DebianRevisionNumber>_<Arch>.deb
Note that foo is supposed to be the package name. This naming
convention is rather new, and some packages have slightly different
name formats. As a check, one can learn the package name associated
with a particular Debian archive file (.deb file) in one of these
ways:
o inspect the "Packages" file in the directory where it was stored in
a Debian FTP archive site. This file contains a stanza describing
each package; the first field in each stanza is the formal Package
Name.
o use the command dpkg --info foo_VVV-RRR.deb. This sends a message
to STDOUT which gives, 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 "960428" and "2.7.2.l.3".
The RRR component is the Debian revision number, and is specified by
the Debian developer (or an individual user if he chooses to build the
package himself). This number corresponds to the revision level of
the Debian package (which includes the Debian-specific Makefile,
called debian.rules, as well as the Debian control file, usually
called debian.control). Thus, a new revision level usually signifies
changes in the Debian Makefile, the Debian control file, the
installation or removal scripts, or in the configuration files used
with the package.
The Arch component identifies the processor for which the package was
built. This is commonly i386, which refers to chips in the 80x86
family of vintage 80386 or later. ``Other possibilities'' include
m68k for processors in the Motorola 680x0 family, etc.
6.4. What's a Debian control file?
Specifics regarding the contents of a Debian control file are provided
in the manual page deb-control (5). Briefly, a sample control file is
shown below for the Debian package libc5_5.2.18-9.deb:
PACKAGE: libc5
SECTION: base
SOURCE: libc5
DESCRIPTION: The Linux C library version 5 (run-time libraries).
Includes shared libraries needed to run programs built with libc 5.
MAINTAINER: David Engel <david@ods.com>
VERSION: 5.2.18-9
PRE-DEPENDS: ldso (>=1.7.14-2)
CONFLICTS: elf-libc, pthreads1
REPLACES: elf-libc
PROVIDES: elf-libc, pthreads1
ARCHITECTURE: i386
The first line 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 second line gives the "section" where this Debian package is
stored at the Debian FTP sites. This is the name of a subdirectory
(within one of the main directories, see ``more about the Debian FTP
directory structure'') where the package is stored.
The Source field identifies the source package from which the binary
package was made. Normally, this is the same as the name of the
package itself. It can be different, however, when one source package
actually provides more than one binary package. For example, three
different binary packages related to the Java Developer's Kit are
produced from the single jdk source package: one for systems with
Motif libraries (jdk-shared), one for systems without Motif (jdk-
static), and one package common to both (jdk-common).
The Description field gives a brief summary of the package's features,
and the Maintainer field names the Debian package developer and his
email address. 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.
The Pre-Depends field gives a list of packages that have to be
available in order to make dpkg even try to install a package. This
feature is for expert use only.
The Conflicts field tells the user (and the Debian package maintenance
tools) what other packages cannot co-exist with the programs in this
package. The Replaces field tells what packages will be replaced when
this one is installed. The Provides field tells what packages will be
installed by this package; this is a mechanism by which multiple
packages can be distributed as a single package, which is in some
cases an aid to the package maintenance system.
The final field (Architecture) specifies the chip for which this
particular binary was compiled.
6.5. What's a Debian Conffile?
Conffiles are listings of configuration files, usually placed in /etc,
that the package management system will not overwrite when a 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,
users can inspect the contents of
/var/lib/dpkg/info/package_name.conffiles For example, the
netbase.conffiles package contains these entries:
/etc/init.d/netbase
/etc/gateways
/etc/protocols
/etc/services
/etc/hosts.allow
/etc/hosts.deny
/etc/rpc
6.6. What's a Debian preinst, postinst, prerm, and postrm script?
These files are executable scripts which are automatically run before
or after a package is installed. 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 executes the configuration of a package once that
package has been unpacked from its Debian archive (".deb") file.
Many 'preinst' scripts also 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 the user
for input, and/or warn the user that if he accepts default
values, he should remember to go back and re-configure that
package as the situation warrants. Many 'postinst' scripts then
execute any commands necessary to start or restart a service
once a new package has been installed or upgraded. It is a good
idea to check the contents of the 'postinst' script for any
configuration advice, when trying out a package for the first
time.
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. (See notes on ``Virtual packages''.)
All of the control files can be found in /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.
6.7. What's a Required/Important/Standard/Optional/Extra package?
Each Debian package is assigned a priority by the distribution
maintainers, as an aid to the package management system. The
priorities are:
o Required packages are absolutely essential. Required packages are
necessary for the functioning and repairability of the system. 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
unuseable, but they do have enough functionality to allow the
sysadmin to boot and install more software.
o 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 X11 or TeX or any
other large applications. These packages only constitute the bare
infrastructure.
o Standard packages are standard on any Linux system, including a
reasonably small but not too limited character-mode system. This
is what will install by default if users don't select anything
else. It doesn't include many large applications, but it does
include Emacs (this is more of a piece of infrastructure than an
application) and a reasonable subset of TeX and LaTeX (if this
turns out to be possible without X).
o Optional packages include all those that you might reasonably want
to install if you didn't know what it was or don't have specialized
requirements. This includes X11, a full TeX distribution, and lots
of applications.
o Extra packages conflict with others with higher priorities, or are
only likely to be useful if you already know what they are or have
specialised requirements.
6.8. What's 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 tin and trn programs are both news readers, and
should therefore satisfy any dependency of a program that required a
news reader on a system in order to work. They are therefore both
said to provide the "virtual package" called news reader.
Similary, smail 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 existence 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 the
section on ``diversions''.
6.9. What is meant by saying that a file
Depends/Recommends/Suggests/Conflicts/Replaces/Provides another pack-
age ?
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:
o 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.
o 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.
o Package A suggests Package B if B contains files that are related
to (and usually enhance) the functionality of A.
o 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".
o Package A replaces with Package B when files installed by B are
removed and (in some cases) over-written by files in A.
o 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.
6.10. What is meant by Pre-Depends?
"Pre-Depends" is a special dependency.
In the case of most packages, dpkg will unpack its archive file (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 filesystem, 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.
6.11. What is meant by unknown/install/remove/purge/hold in the pack-
age status?
These "want" flags tell what the user wanted to do with a package (as
indicated either by the user's actions in the "Select" section of
dselect, or by the user's direct invocations of dpkg). Their meanings
are:
o unknown - the user hasn't said whether they want the package
o install - the user wants the package installed or upgraded
o remove - the user wants the package removed (but doesn't want to
remove any existing configuration)
o purge - the user wants the package to be removed completely
o hold - the user wants this package not to be processed, i.e.,
he wants to keep the current version with the current status
whatever that is.
7. The Debian Package Management Tools
7.1. What program(s) does Debian provide for managing its packages?
7.1.1. dselect
This program is a menu-driven interface to the Debian package
management system. It is particularly useful for first-time
installations and large-scale upgrades. dselect can
o guide the user as he/she chooses among packages to install or
remove, ensuring that no packages are installed that conflict with
one another, and that all packages required to make each package
work properly are installed;
o warn the user about inconsistencies or incompatibilities in their
selections;
o determine the order in which the packages must be installed;
o automatically perform the installation or removal; and
o guide the user through whatever configuration process are required
for each package.
dselect begins by presenting the user with a menu of 7 items, each of
which is a specific action. The user can select one of the actions by
using the arrow keys to move the highlighter bar, then pressing the
ENTER key to select the highlighted (highlit?) action.
What the user sees next depends on the action he selected. If he
selects any option but Access or Select, then dselect will simply
proceed to execute the specified action: e.g., if the user selected
the action Remove, then dselect would proceed to remove all of the
files selected for removal when the user last chose the Select action.
Both the Access menu item and the Select menu item lead to additional
menus. In both cases, the menus are presented as split screens; the
top screen gives a scrollable list of choices, while the bottom screen
gives a brief explanation ("info") for each choice.
Extensive on-line help is available: Use the '?' key to get to a help
screen, then use the '.' key to see each of the several pages of help
one screen at a time.
Some users find it easier to navigate dselect when it is colorized.
To see color screens in dselect, be sure that you've executed: export
TERM=linux before invoking dselect.
The order in which the actions are presented in the first dselect menu
represents the order in which a user would normally choose dselect to
install packages. However, a user can pick any of the main menu
choices as often as needed (including not at all, depending on what
one wants to do).
o Begin by choosing an "Access Method". This is the method by which
the user plans on accessing Debian packages; e.g., some users have
Debian packages available on CD-ROM, while others plan to fetch
them using anonymous ftp. (To use the latter approach, a user will
have had to fetch and install the package dpkg-ftp before running
dselect.) The selected "Access Method" is stored in the file
/var/lib/dpkg/cmethopt after dselect exits, so if it doesn't
change, then this option need not be invoked again.
o Then "Update" the list of available packages. To do this, dselect
reads the file "Packages.gz" which should be included in the top
level of the directory where the Debian packages to be installed
are stored. (But if it's not there, dselect will offer to make it
for you.)
o Select specific packages for installation on his system.
After choosing this menu item, the user is first presented with a
full screen of help; he can exit it (and any help screen) by
pressing the SPACEBAR. Better (for first time users) is to read
all of the help screen, but repeatedly pressing the '.' key to
fetch one page of help after another. Once the user exits the Help
screen, he sees the split-screen menu for choosing packages to
install (or remove). The top screen is a relatively narrow window
into the list of Debian's nearly 500 packages; the bottom screen is
a window into "info" about the package or group of packages which
are highlighted in the top.
First-time users are often confused by these aspects of the Select
screen:
o "Deselecting" a packages: One can specify which packages should be
removed (previously called "deselecting" an item) by highlighting a
package name or the label for a group of packages (e.g., "All") and
then pressing either:
o the '-' key. This removes most of the files associated with the
package, but NOT the configuration files, i.e., those listed in
/var/lib/dpkg/info/PACKAGENAME.conffiles
o the '_' key. This removes every file that's part of the package.
Note that if you "de-select" "All Packages" your system will be
reduced to the initial installed base packages. This is probably
what you wanted.
o Putting a package "on hold" (by pressing '='): This effectively
tells dselect not to upgrade a package even if the version
currently installed on your system is not as recent as the version
that's available in the Debian repository you are using (this was
specified when you set the Access Method). (The version that's
available in the repository is given in the file Packages.gz that's
read when the "Update" menu choice is activated.
Putting a package on "unhold" (by pressing ':'): This is the
default, and means that the packages will be upgraded if a newer
version is available.
o The order in which the packages are presented: The default order
is to present packages by Priority; within each priority, packages
are presented in order of the directory (a.k.a. section) of the
archive in which they are stored. Given this sort order, some
packages in section A (say) may be presented first, followed by
some packages in section B, followed by more packages (of lower
priority) in section A. Users can select a different presentation
order by using the 'o' key to cycle between various options for
sorting the packages.
o Meanings of the labels at the top of the screen: The labels at the
top can be expanded by using the 'v' (verbose) key. This action
pushes much of the text that formerly fit onto the display off to
the right. To see it, press the right arrow; to scroll back to the
left, press the left arrow.
o What to do with a package conflict/dependency screen: If a user
selects (for installation or removal) a package, e.g. foo.deb that
depend on or recommend another package, e.g., blurf.deb, then
dselect will place the user in a sub-screen of the main selection
screen. This process begins by presenting the user with a full-
screen Help file, which can be escaped by pressing SPACEBAR.
Thereafter, the user can choose among the related packages,
accepting the suggested actions (to install or not), or rejecting
them. To do the latter, press SHIFT-D; to return to the former,
press SHIFT-U. In any case, the user can save his selections and
return to the main selection screen by pressing SHIFT-Q.
o Users returning to the main menu can then select either the
"Install" menu item, followed by the "Configure" menu item to
unpack and then be guided through the configuration files for the
selected packages. Alternatively, users wishing to remove files
can choose the "Remove" menu item. At any point, users can choose
"Quit" to exit dselect; dselect stores users' selections in the
file /var/lib/dpkg/status.
7.1.2. dpkg:
This is the main package management program, dpkg can be invoked with
many options. Some common uses are:
o Find out all the options: dpkg --help.
o Print out the control file (and other information) for a specified
package: dpkg --info foo_VVV-RRR.deb
o Install a package (including unpacking and configuring) onto the
file system of the hard disk: dpkg --install foo_VVV-RRR.deb.
o 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'' script associated with the package.
o Configure a package that's already been unpacked: dpkg --configure
foo. Among other things, this action runs the ``postinst'' 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).
o 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*
o Remove a package (but not its configuration files): dpkg --remove
foo.
o Remove a package (including its configuration files): dpkg --purge
foo.
o List the installation status of packages containing the string
'foo*': dpkg -l foo*.
7.1.3. dpkg-deb
This tools manipulates Debian archive (.deb)files. Some command uses
are:
o Find out all the options: dpkg-deb --help.
o Determine what files are contained in a Debian archive file: dpkg-
deb -c foo_VVV-RRR.deb)
o Extract the files contained in a named Debian archive into a user
specified directory: dpkg-deb -x 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.
More information is given in the section 1 manual page for dpkg-
deb.
7.1.4. dpkg-split
This Perl script splits large package into smaller files (e.g., for
writing onto a set of floppy disks), and can also be used to merge a
set of split files back into a single file. It can only be used on a
Debian system, since it calls the program dpkg-deb to parse the debian
package file into its component records. For example, to split a big
.deb file into N parts,
o Execute the command dpkg-split -s foo.deb. This will produce N
files each of approximately 460 KBytes long in the current
directory.
o Copy those N files to floppy disks.
o Copy the contents of the floppy disks onto the hard disk of your
choice on the other machine.
o Join those part-files together using dpkg-split -j "foo*".
7.2. Debian claims to be able to update a running program; how is
this accomplished?
Debian GNU/Linux provides a program called the start-stop-daemon which
is used by installation scripts to start daemons at boot time or to
stop daemons when the kernel runlevel is changed (e.g., from multi-
user to single-user or to halt). The start-stop-daemon command is
also used when a new package containing a daemon is installed, to stop
running daemons, and restart them as necessary, e.g., when a package
is being installed with an updated configuration script.
7.3. 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 -l. This prints out a one-line summary for
each package, giving a 2-letter status symbol, the package name, the
version which is installed, and a very brief description.
To learn the status of packages whose names match the string any
pattern beginning with 'foo' by executing the command: dpkg -l "foo*"
To get a more verbose report for a particular package, execute the
command: dpkg --status foo.
7.4. How can I find out what package produced a particular file?
To identify the package that produced the file named foo execute
either:
o dpkg -S filename.
This searches through the lists of installed files. This is
(currently) equivalent to searching all of the files having the
file extension of .list in the directory /var/lib/dpkg/info/.
o grep foo Contents, or zgrep foo Contents.gz.
This searches for files which contain the substring foo in their
full path names. The files Contents and Contents.gz reside in the
major package directories (Debian-1.1, non-free, contrib, etc.) at
a Debian FTP site. 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.
8. Getting and Installing Debian GNU/Linux
8.1. Where/how can I get the Debian installation disks?
You can get the installation disks by downloading the appropriate
files from any Debian FTP site: <ftp://ftp.debian.org/debian/> and
its mirrors <http://www.debian.org/ftplist.html>. From the directory
Debian-1.1/disks-i386/current, you'll need:
The Boot Disk.
If your system can boot from a 1.44 MByte floppy disk drive,
download the file called boot1440.bin. On the other hand, if
your system can boot only from a 1.22 MByte floppy disk drive,
download the file called boot1220.bin.
The Root Disk.
Download the file called root.bin. It will fit on either a 1.44
MByte or a 1.2 MByte floppy disk.
The Base Disks.
These disks contain the software that's necessary to have a
bare-bones system. Depending on your configuration, you may
need 1, 3, or 4 of these disks. (See notes below.)
You may of course get these disks from a friend. You can make as many
copies as you want. Debian is freely redistributable, provided you
follow a few simple rules. For more information, see The GNU General
Public License <http://www.cygnus.com/library/misc/license.html>.
If you cannot get copies of the installation disks from one of the
Debian FTP sites or from a friend, then make a request to one of the
Debian mailins lists. See ``the debian-user mailing list''. The
likelihood is very high that someone will be willing to help.
8.2. OK, I've got the disks; how do I install the system?
Complete, detailed instructions are given in the same FTP sites as the
installation disks. Fetch the plain ASCII file
<ftp://ftp.debian.org/Debian-1.1/disks-i386/current/install.txt>, the
Postscript file <ftp://ftp.debian.org/Debian-1.1/disks-
i386/current/install.ps>, or view them directly on the WWW
<ftp://www.debian.org/Debian-1.1/disks-i386/current/install.html>.
8.3. How (and on what media) can I get the Debian packages?
Once the base system has been installed, you can complete the
installation of your Debian GNU/Linux system by accessing packages on
any (or several) of these media:
o a ``CD-ROM'' containing a Debian distribution.
o a remote ``NFS'' server.
o a partition of your ``hard disk''.
o a collection of ``floppy disks''.
o a remote system accessible by ``anonymous ftp''.
In each case, you can use either
o ``dselect'', Debian's user-interface program to its package system.
(This will help you mount the device containing the Debian package
files (if necessary), and then guide you through the selection of
packages and their installation on your system.) Or,
o use ``dpkg'' directly to control the installation of individual
packages. Debian gurus quizzically refer to this approach as
installing packages "by hand".
8.4. How do I get and install the Debian distribution from CD-ROM?
Linux supports the ISO 9660 (CD-ROM) file system with Rock Ridge
extensions (formerly known as "High Sierra"). Several vendors provide
the Debian distribution in this format; these vendors have directly
supported the Debian project:
o I-Connect Co.: I-Connect provides the master FTP system used by
Debian developers, and its network connection and system
administration. They provide our 100 developers with free accounts
on a system that is exclusively for our use, and they run our DNS
domain. They also maintain several Debian packages. Use the
following contact info to order their CD-ROM:
o WWW:http://www.i-connect.net/i-connect/services/cdrom.html
<http://www.i-connect.net/i-connect/services/cdrom.html>
o Email (sales): sales@i-connect.net
o Email (help): help@i-connect.net
o Phone from inside the US: 1-503-677-2900
o Phone from outside the US: +1-503-677-2900
o Postal address:
iConnect Corp.
14355 SW Allen Blvd., Suite 140
Beaverton, OR 97008
o Flexible Software: This company maintains 8 Debian packages, and
puts a lot of manpower into supporting users on the debian-user
mailing list and refining the system design with our developers.
They have carefully documented the development of one of the two
methods used to upgrade from Debian 0.93 to Debian 1.1.
o Email (sales): dwarf@polaris.net
o Postal address:
Flexible Software
1000 McCrackin Road
Tallahassee, FL 32308
To install packages provided on a CD-ROM, you must have CD-ROM support
built into the kernel you have. This may require a special kernel
(see the kernels in the directory Debian-1.1/disks-i386/special/), a
custom modification of the file /etc/conf.modules, or (least likely
nowadays) a special argument on the boot command line.
To mount a CD-ROM under the mount point /cdrom (a directory which
should have been created during installation), use these commands:
o mount -t iso9660 /dev/hdd /cdrom if the CD-ROM is an IDE drive on
the secondary IDE controller, or
o mount -t iso9660 /dev/scd0 /cdrom if the CD-ROM is a SCSI drive, or
o mount -t iso9660 /dev/xxxxx /cdrom where xxxxx refers to CD-ROm's
which are sbpcd, cdu31a, or some other proprietary (non-IDE) drive.
8.5. How do I get and install the Debian distribution from an NFS-
mounted drive?
Debian packages on remote hosts can be installed via the Network File
System using a SLIP, PPP, PLIP or Ethernet connection. SLIP and PPP
require that the the netbase and netstd packages be installed first.
These packages are not part of the Debian base system, and must be
obtained by one of the other methods described in this section.
No special kernel configuration (other than the network drivers for
SLIP, PPP, PLIP, or one of the Ethernet cards) is necessary to access
a remote filesystem using NFS. As with all network communication, the
appropriate ifconfig and route commands will have to be issued before
accessing a remote disk using NFS.
To mount a network-accessible file system using NFS (say,
/var/spool/debian) under the local directory /mnt, issue the command
o mount -t nfs host@Fully-qualified.domain.name:/var/spool/debian -o
ro,nosuid,soft /mnt
To ensure that the filesystem is always accessible, the appropriate
string could be added to /etc/fstab:
o rulway.leidenuniv.nl:/var/spool/ftp.pub.linux.debian /mnt/debian
nfs ro,nosuid,soft
The preceding example shows the appropriate entry for the NFS site at
Leiden University, the Netherlands, which is the only FTP site known
to export Debian via NFS officially at this time.
8.6. How can I get/install the Debian distribution from a set of
floppy disks?
Copy the Debian packages onto formatted floppy disks. Either a DOS,
the native Linux "ext2", or the "minix" format will do; one just has
to use a mount command appropriate to the floppy that's being used.
Using floppy disks has these complications:
o Short MS-DOS filenames: If you are trying to place Debian package
files onto MS-DOS formatted disks, you will find that their names
are generally too long, and do not conform to the MS-DOS 8.3
filename limitation. To overcome this, Debian developers make all
of their packages available by 8.3 filenames in separate "msdos"
subdirectories (Debian-1.1/msdos-i386, non-free/msdos-i386, and
contrib/msdos). The files in these subdirectories are merely
symbolic links to the Debian archive files; they only differ from
the files in the binary-i386, etc. directories by having shorter
file names.
o Large file sizes: Some packages are larger than 1.44 MBytes, and
won't fit onto a single floppy disk. To solve this problem, use
the ``dpkg-split'' tool, available in the tools directory at
<ftp://ftp.debian.org/debian/> and its mirrors
<http://www.debian.org/ftplist.html>.
You must have support in the kernel for floppy disks in order to read
and write to floppy disk; most kernels come with floppy drive support
included in them.
To mount a floppy disk under the mount point /floppy (a directory
which should have been created during installation), use:
o mount -t msdos /dev/fd0 /floppy if the floppy disk is in drive A:
and has an MS-DOS filesystem,
o mount -t msdos /dev/fd1 /floppy if the floppy disk is in drive B:
and has an MS-DOS filesystem,
o mount -t ext2 /dev/fd0 /floppy if the floppy disk is in drive A:
and has an ext2 (i.e., a normal Linux) filesystem.
8.7. How can I get/install the Debian distribution from my own hard
disk?
The Debian packages can be installed from a hard disk on your system,
either IDE, EIDE, SCSI (including Jaz drives), or a drive connected
through a parallel port.
Kernel support must of course be available for the type of drive you
have. The appropriate drivers are:
o CONFIG_BLK_DEV_IDE for IDE or EIDE drives; most kernels include
this driver.
o CONFIG_SCSI for SCSI drives (including Jaz drives), along with one
of the (many) drivers for your particular SCSI interface.
o CONFIG_SCSI_PPA for the parallel port version of ZIP drives.
To mount partition X (X =1,2,3, or 4) for a given drive under the
directory /mnt (which should have been created during installation),
use:
o mount -t msdos /dev/hdaX /mnt if the disk is drive C: and has an
MS-DOS filesystem,
o mount -t ext2 /dev/sdaX /mnt if the disk is a SCSI drive and has
the lowest SCSI ID of any SCSI device on your system, and has an
ext2 filesystem,
o mount -t ext2 /dev/sdbX /mnt if the disk is a SCSI drive and has
the second lowest SCSI ID of any SCSI device on your system, and
has an ext2 filesystem,
o mount -t ext2 /dev/fd0 /floppy if the floppy disk is in drive A:
and has an ext2 (i.e., a normal Linux) filesystem.
o mount -t msdos /dev/ppa0 /mnt if the disk is a Zip drive with an
MS-DOS filesystem.
o mount -t ext2 /dev/ppa0 /mnt if the disk has an ext2 filesystem.
Note that files on a disk partition having an MS-DOS filesystem must
conform to the DOS filename limitation of 8 characters plus a 3
character extension. Files in the Debian-1.1/msdos-i386, non-
free/msdos-i386, and contrib/msdos directories conform to this
limitation.
8.8. How can I get and install the Debian distribution directly from
a remote ftp site?
Install the Debian tool ``dpkg-ftp''. This package is currently
installed in the directory project/experimental at
<ftp://ftp.debian.org/debian/> and its mirrors
<http://www.debian.org/ftplist.html>. To do install a package, see
notes on ``dpkg''.
Then invoke the program dselect, which will call dpkg-ftp for you,
guide you through the selection of packages, then install the
packages, without every downloading the packages themselves to your
machine. This method is designed to save the user both disk space and
time. Note that no special kernel configuration is needed to access
and install Debian packages by this method.
To use this service of dselect, you will need to know:
o the fully qualified domain name of the anonymous ftp site you plan
to use. For example, you might use ftp.nluug.nl.gov if you live in
or near the Netherlands.
o the directory which contains the files you want to install, or the
subdirectories which contain files you want to install. This
directory must contain a file called "Packages" (or its compressed
equivalent, "Packages.gz"). For example, if you want to install
files from the most uptodate revisions of the current Debian
distribution, then (for ftp.nluug.nl) you would specify the
directory pub/os/Linux/distr/Debian/Debian-1.1.1/.
8.9. How can I get and install the Debian distribution from a tape?
At present, installing packages directly from tape is not supported.
One can however, use tar, cpio, or afio to copy Debian archive files
onto a tape, then copy them onto your local disk for installation. In
the same vein, floppy disks containing "tar" files would have to be
copied onto a local disk before they could be managed with the Debian
package tools.
8.10. What's the latest version of Debian?
Currently there are two versions of the Debian distribution:
o "1.1": this is stable software, and will not change.
o the "development" version. This is updated continuously. You can
retrieve packages from the "development" archive on our FTP sites
and use them to upgrade your system at any time.
Approximately three months from today, the "development" software will
have been stabilized and made into Debian 1.2. Further releases will
follow at three-month intervals.
9. Keeping Your Debian System Up To Date
9.1. How can I upgrade my Debian 0.93 (or earlier) distribution,
based on a.out format binaries, to 1.1, based on ELF binaries?
The directory /debian/upgrades contains files needed by users
upgrading from Debian 0.93R6 to Debian 1.1. There are two ways to
upgrade:
o the manual way, installing the packages by hand. Instructions are
in upgrade_manual.doc. You will also need the files UpGrade,
base_list, and dpkg-*.i386.deb.
o using dselect to upgrade all the packages en masse. Instructions
are in upgrade_dselect.doc. You will also need dpkg-*.i386.deb.
Note that the version of dpkg in this directory has the a.out binary
format. The versions of dpkg in the unstable and stable trees have
the ELF format.
9.2. How can I keep my Debian system current?
One could simply execute an anonymous ftp call to a Debian archive,
then peruse the directories until he 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 the
Debian distribution 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 an automated programs. Three different packages are
available for this purpose:
o mirror. This perl script, and its (optional) manager program
called mirror-master, can be used to fetch user-specified parts of
a directory tree from a specified host via anonymous ftp. mirror
is particularly useful for downloading large volumes of software.
After the first time files have been downloaded from a site, a file
called ".mirrorinfo" is stored on the local host. Changes to the
remote filesystem are tracked automatically by mirror, which
compares this file to a similar file on the remote system.
The mirror program is generally useful for updating local copies of
remote directory trees. The files fetched need not be Debian
files. (Since mirror is a Perl script, it can also run on non-Unix
systems.) Though the mirror programs provides mechanisms for
excluding files whose names match user-specified strings, this
program is most useful when the objective is to download whole
directory trees, rather than selected packages.
The mirror program has been packaged for the Debian distribution,
and is found in the directory Debian-1.1/binary-all/net in the
Debian FTP archive.
o dftp. This C shell script can be used to fetch user-specified
Debian packages from a specified host. After the first time files
have been downloaded from a site, a file called "Packages.gz" is
stored on the local host. Changes to the remote filesystem are
tracked automatically by dftp, which compares this file to a
similar file on the remote system.
The dftp program can be used to call ``dselect'', thereby providing
an integrated way to fetch and update the Debian packages on one's
system.
The dftp program is available as a script in the directory
contrib/tools in the Debian FTP archive.
o dpkg-ftp. This is a Perl script that allows one to install Debian
packages that are stored on a remote Debian FTP archive. For users
with limited disk space and/or limited bandwidth access to the
Internet, this approach is particularly beneficial.
Alternatively, the dpkg-ftp program can be invoked from within
dselect, thereby allowing a user the ability to download files and
install them directly in one step. To do this, bring up the
dselect program, choose option "0" ("Choose the access method to
use"), highlight the option "ftp" then specify the remote hostname
and directory. dpkg-ftp will then automatically download the files
that are selected (either in this session of dselect or earlier
ones).
Note that, unlike the mirror program, dpkg-ftp does not grab
everything at a mirror site. Rather, it downloads only those files
which you have selected (when first starting up dpkg-ftp, and which
need to be updated.
The dpkg-ftp program is available both as a gzip-compressed tar
archive and a Debian package in the directory project/experimental
in the Debian FTP archive. dpkg-ftp is now part of the base Debian
distribution; it is included in the first "base" disk used in the
installation.
All of the above programs can be set up (using the cron facility) to
be executed automatically at specific times.
9.3. Must I go into single user mode in order to upgrade a package?
No. Packages can be upgraded in place, even in running systems. The
Debian distribution has a start-stop-daemon that is invoked to stop,
then restart running process if necessary duing a package upgrade.
9.4. Do I have to keep all those .deb archive files on my disk?
No. If you've downloaded the files to your disk (which isn't
absolutely necessary (see ``dpkg-ftp'' or ``dftp''), then after you've
installed the packages, you can simply rm them from your system.
9.5. How can I keep a log of the packages I added to the system?
dpkg keeps a record of the packages that have been unpacked,
configured, removed, and/or purged, but does not (currently) keep a
log of terminal activity that occured while a package was being so
manipulated. Some users overcome this simply by using tee:
dpkg -iGROEB stable/binary non-free/binary contrib/binary | \
tee -a > /root/dpkg.log
10. Debian and the kernel
10.1. What tools does Debian provide to build custom kernels?
Users who wish to (or must) build a custom kernel are encouraged to
download the package kernel-package_VVV_all.deb, which contains the
script to build the kernel package, and provides the capability to
create a Debian kernel-image package just by running the command make-
kpkg kernel_image in the top-level kernel source directory. Help is
available by executing the command make-kpkg --help, and through the
section 8 manual page for make-kpkg.
Users must separately download the source code for the most recent
kernel (or the kernel of their choice) from their favorite Linux
archive site.
To build a custom kernel, users must have these packages installed:
gcc, libc5-dev, bin86, binutils, gawk, make, gzip, and grep.
Executing the command dpkg --install kernel-package_VVV_all.deb sets
up the directory /usr/src/linux, and sets up the link /usr/src/linux
to point to the directory containing the kernel sources appropriate to
the kernel version contained in the package. In the case of
Debian-1.1, this kernel version is 2.0.0.
Detailed instructions for using the package are given in the file
/usr/doc/kernel-package/README. Briefly, one should:
o Unpack the kernel sources, and cd to the newly created directory.
o Modify the kernel configuration using one of these commands:
o make config (for a tty one-line-at-a-time-interface).
o make menuconfig (for an ncurses-based menu driven interface).
o make xmenuconfig (for an X-windows interface).
Any of the above steps generates a new .config in the top-level
kernel source directory.
o Execute the command: make-kpkg -r Custom.N kernel_image, where N is
a revision number assinged by the user. The new Debian archive
thus formed would have revision Custom.1, e.g., kernel-
image-2.0.7-Custom.1_i386.deb for the Linux kernel 2.0.7.
o Install the package created.
o dpkg -i /usr/src/kernel-image_VVV-Custom.N_i386.deb to install the
kernel itself. The installation script will:
o run the boot loader, LILO (if it is installed),
o install the custom kernel in /boot/vmlinuz_VVV-Custom.N, and set up
appropriate symbolic links to the most recent kernel version.
o prompt the user to make a boot floppy. This boot floppy will
contain the raw kernel only. See additional notes for making a
``custom boot floppy''.
o To employ a secondary boot loaders (e.g., loadlin), copy this image
to other locations (e.g., an MS-DOS partition).
10.2. How can I make a custom boot floppy?
This task is greatly aided by the Debian package boot-floppies_VVV-
RRR.deb, normally found in the binary/devel section of the Debian FTP
archive. Shell scripts in this package produce boot floppies in the
SYSLINUX format. These are MS-DOS formatted floppies whose master
boot records have been altered so that they boot Linux directly (or
whatever other operating system has been defined in the syslinux.cfg
file on the floppy). Other shell scripts in this package produce
emergency root disks and can even reproduce the base disks.
When the boot-floppies package is installed, it produces files which
reside in /usr/src/boot-floppies-VVV, including the three scripts,
called bootdisk.sh, rootdisk.sh, and basedisk.sh. Users of these
scripts are encouraged to read them and customize as appropriate. In
particular, one should include the kernel of your choice when invoking
the bootdisk.sh script. Be aware that this kernel cannot be used to
load the root disk into a RAMDISK unless it was compiled with
CONFIG_RAMDISK=y, and CONFIG_INITRD=y.
The command
writes the kernel-image-2.0.0 package to the 1.44 MByte disk in drive
A:.
Be sure to include the editor and whatever other tools you prefer when
building your custom root disk with rootdisk.sh.
10.3. What special provisions does Debian provide to deal with mod-
ules?
Debian's modconf package provides a shell script (/usr/sbin/modconf)
which can be used to customize the configuration of modules. This
script presents a menu-based interface, prompting the user for
particulars on the loadable device drivers in his system. The
responses are used to customize the file /etc/conf.modules (which
lists aliases, and other arguments that must be used in conjuction
with various modules), and /etc/modules (which lists the modules that
must be loaded at boot time).
Like the (new) Configure.help files that are now available to support
the construction of custom kernels, the modconf package comes with a
series of help files (in /usr/lib/modules_help) which provide detailed
information on appropriate arguments for each of the modules.
11. Customizing your installation of Debian GNU/Linux
11.1. Every distribution seems to have a different boot-up method.
Tell me about Debian's.
Like all Unices, Debian Linux boots up by executing the program init.
The configuration file for init (which is /etc/inittab) specifies that
the first script to be executed should be /etc/init.d/boot. This
script checks and mounts file systems, loads modules, starts the
network services (by calling the script /etc/init.d/network), sets the
clock, performs other initialization, and then runs all of the scripts
(except those with a '.' in the filename) in /etc/rc.boot. The latter
script sets the default keyboard, recovers lost editor files, and
configures the serial ports.
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 6 runlevels: 0 (halt the system), 1 (single-user
mode), 2 through 5 (various multi-user modes), and 6 (reboot the
system). Debian Linux 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.
In fact, 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', or 'restart', and will
then do the task indicated by the argument. For example, with the
argument 'restart' the command /etc/init.d/sendmail restart restarts
the sendmail daemon. These scripts can be used even after a system
has been booted to control various processes.
11.2. It looks as if Debian doesn't use rc.local to customize the
boot process; what facilities are provided?
Suppose a system needs to execute script foo on start-up, or on entry
to a particular (System V) runlevel. Then the system administrator
should:
o Enter the script foo into the directory /etc/init.d/.
o Run the Debian command update-rc.d with appropriate arguments, to
set up links between the (command-line-specified) directories rc?.d
and /etc/init.d/foo. Here, '?' is a number from 0 through 6 and
corresponds to each of the System V runlevels.
o Reboot the system.
The command update-rc.d will set up links between files in the
directories rc?.d and the script in /etc/init.d/. Each link will
begin with a 'S' or a 'K', followed by a number, followed by the name
of the script. Scripts beginning with 'S' in /etc/rcN.d/ are executed
when runlevel N is entered. Scripts beginning with a 'K' are executed
when leaving runlevel N.
One might, for example, cause the script foo to execute at bootup, by
putting it in /etc/init.d/ and installing the links with update-rc.d
foo defaults 19. The argument 'defaults' refers to the default
runlevels, which are 2 through 5. The argument '19' ensures that foo
is called before any scripts containing numbers 20 or larger. the
appropriate time.
11.3. 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
won't know about those configuration files if they're 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 config 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.
11.4. How do I override a file installed by a package so that a dif-
ferent 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:
o Overwrite /bin/login with bin/login-local.
The package management system won't know about this change, and
will simply overwrite /bin/login-local whenever login (or any
package that provides login is installed or updated.
Rather, do
o Execute dpkg-override --divert /bin/login.debian /bin/login in
order to cause all future installations of the Debian login
packages to write the file /bin/login to /bin/login.debin/ instead.
o Then execute cp login-local /bin/login to move your own locally-
built program into place.
More notes on this technique are given in the file
/usr/doc/debian/package-developer/diversions.txt.gz which is
installed as part of the doc-debian package.
11.5. How can I have my locally-built package included in the list of
available packages that the package management system knows about?
You can do this in either of two ways:
o Use dselect, and select the option "Update list of available
packages". Then execute the command dpkg --avail foo.deb, where
foo.deb is the name of your locally-built Debian archive file.
o Execute the command dpkg-scanpackages BIN_DIR OVERRIDE_FILE
[PATHPREFIX] > Packages.new where:
o BIN-DIR is a directory where Debian archive files (which usually
have an extension of ".deb") are stored.
o OVERRIDE_FILE is a file that's edited by the distribution
maintainers and is usually stored on a Debian FTP archive at
indices/override.main.gz for the Debian packages in the "main"
distribution.
o PATHPREFIX is an optional string that can be prepended to the
Packages.new file being produced.
Once you've built the file Packages.new, tell the package
management system about it by using the command dpkg --update-avail
Packages.new.
11.6. 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.
12. Getting support for Debian Linux
12.1. What other documentation exists on and for a Debian system?
o Installation instructions for the current release: see
<http://www.debian.org/1.1/install>.
o Debian-specific documentation: Avaiable in three ways:
o on installed Debian systems.
The latest versions of the dpkg package come with extensive new
programmers' manual and Debian policy manual which are installed
into the directory /usr/doc/dpkg. These documents are now
available in the "unstable" distribution, but will be included in
the next release.
Users who install the package doc-debian_VVV-RRR.deb will find
additional Debian-specific documentation in /usr/doc/debian. This
package is stored in the Debian-1.1/binary/doc section in the
Debian FTP archives.
o on the WWW: See .
o at Debian FTP mirror sites: See the directory doc/, or doc/ (which
is just a link to doc).
o Documentation on installed Debian packages: Most packages have
files that are unpacked into /usr/doc and /usr/doc/examples.
o Documentation on the Linux project: The Debian package doc-
linux_VVV-RRR.deb installs all of the most recent versions of the
HOWTO's and mini-HOWTO's from the Linux Documentation Project.
This package is in the Debian-1.1/binary/doc section in the FTP
archives.
o Unix-style 'man' pages: Most commands have manual pages written in
the style of the original Unix 'man' files. They are referenced by
the section of the 'man' directory where they reside: e.g., foo(3)
refers to a man page which resides in /usr/man/man3, and it can be
called by executing the command: man 3 foo, or just man foo if
section 3 is the only one containing a page on foo. One can learn
which directory of /usr/man contains a certian man page by
executing man -w foo.
New Debian users should note that the 'man' pages of many general
system commands are not available until they install these packages
(both of which are normally stored in the Debian-1.1/binary/doc
directory of the Debian FTP archive:
o manpages_VVV-RRR.deb (or manpages-de_VVV-RRR.deb for German text).
o man_VVV-RRR.deb, which contains the man program itself, and other
programs for manipulating the manpages.
o 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. Its main
advantage over the original require the WWW, however; info can be
run from a plain text console. It was designed by Richard Stallman
and preceded the WWW. The program that manipulates `info' files is
installed as a separate package info_VVV-RRR.deb, usually stored in
the directory Debian-1.1/binary/doc on the FTP archive.
12.2. Are there any on-line resources for discussing Debian?
There are several Debian-related mailing lists:
o debian-announce@lists.debian.org (moderated). (Usually) major
system announcements. On average, fewer than one message per week
are posted here.
o debian-changes@lists.debian.org. Announcements of new package
uploads for the Debian system. This list may carry several
announcements in a day.
o debian-user@lists.debian.org . A mailing list where users can ask
for and receive advice on the use or configuration of Debian
packages or other aspects of Debian Linux. This list is an
invaluable learning resource; there can be 20 messages a day or
more on this list.
o debian-sparc@lists.debian.org . This list is for those involved in
porting Debian software to the Sparc platform.
o debian-alpha@lists.debian.org . This list is for those involved in
porting Debian software to DEC alpha platforms.
o debian-68k@lists.debian.org . This list is for those involved in
porting Debian software to Motorola 680x0 platforms; currently this
means the Atari and Amiga only.
o debian-talk@lists.debian.org .
To subscribe to debian-X (for X in announce, changes, user), send mail
to debian-X-REQUEST@lists.debian.org with the word "subscribe" in the
Subject: header. If you have a forms-capable World Wide Web browser,
you can subscribe to debian-announce and debian-user by using the WWW
form <http://www.rahul.net/perens/Debian/MailingLists.html>. You can
also un-subscribe using that form.
The lists are managed by Anders Chigstrom (ac@netg.se)
Archives of the Debian mailing lists are available on WWW at
<http://www.debian.org/Lists-Archives/>.
Users can address questions to individual package maintainers, since
their email addresses are provided in the Debian control file (see
Section ``Debian control file'' that is included within each package.
One can also learn the maintainers' names and email addresses by
searching the "Packages" file, since this file is just a concatenation
of all the available package control files in a particular directory
tree. To extract a control file from a particular debian package, use
the command,
dpkg --info packageName_VVV-RRR.deb
Another related mailing list, debiangame, is being run by Gary Moore
(htmlurl url="mailto://gary@ssc.com" name="mailto://gary@ssc.com) at
the University of Washington. As the name suggests, it is devoted to
the discussion of games that have been (or might be) packaged for
Debian. To subscribe, send mail to listproc@u.washington.edu, putting
in the message body:
subscribe debiangame FirstName LastName
Both FirstName and LastName are required for ListProc.
Users should post non-Debian-specific questions to one of the Linux
Usenet groups, which are named comp.os.linux.* or linux.*.
Specialized Systems Consultants (a.k.a. SSC) maintains a list of
Linux, Unix, X, and networking newsgroups
<http://www.ssc.com/linux/news.html> on their WWW site.
12.3. What is the code of conduct for the mailing lists?
When using the Debian mailing lists, please follow these rules:
o Don't flame; it's not polite. Besides the people developing Debian
are all volunteers, donating their time, energy and money in an
attempt to bring the Debian project together.
o Don't use four-letter words, some people receive the lists via
packet radio, where swear words are illegal.
o Make sure that you're using the proper list.
o Don't try posting unless you are subscribed. Posting by non-
subscribers was turned off to make the mailing lists usable. Thus,
only postings from email addresses matching those of a subscriber
are accepted. If you often post from other addresses than the one
you subscribe with, mail Anders Chigstrom (ac@netg.se) with the
subject "please add subscriber alias".
o See section ``reporting bugs''. for notes on reporting bugs.
12.4. Are there any other on-line resources dealing with Debian
Linux?
Software in the Public Interest, Inc ., operates a WWW-server at
<http://www.debian.org> which provides additional on-line resources.
See also Section ``on contributing to Debian Linux''.
Generally, users should also exploit the WWW search engines for
addressing specific problems. For example, the DejaNews news search
service is an invaluable resource for exploring Usenet newsgroups.
Try this search:
linux & WD
This tells DejaNews to report any postings containing either the
string "linux" or the string "WD" When I used it, I discovered that my
WD card (which I've only had for 6 months) has been declared outmoded
by Adaptec, now that they've bought WD. So there are no drivers avail-
able. (Bless Adaptec's hearts.)
Or search the WWW using the Altavista Search Engine. For example,
searching on the string "cgi-perl" gives a more detailed explanation
of this package than the brief description field in its control file.
13. The Debian Bug Report System
13.1. Are there logs of known bugs?
The Debian Linux distribution has a bug tracking system which files
details of bugs reported by users and developers. Each bug is given a
number, and is kept on file until it is marked as having been dealt
with.
Copies of this information are available at
<http://www.cl.cam.ac.uk/users/iwj10/debian-bugs/> and
<http://www.debian.org/Bugs/>, but the latter is not up-to-date at
present.
The HTML files, in a form suitable for using as part of an HTTP server
document tree, are in the WebPages subdirectory of the Debian FTP
archive.
The bug reports are also available by anonymous FTP from any Debian
mirror in the directory debian-bugs/html/ for hypertext form, and in
the directory debian-bugs/text/ for plain text form.
13.2. 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:
o By anonymous ftp. Debian mirror sites contain the instructions in
the file debian-bugs/Reporting.html.
o From the WWW. A copy of the instructions is shown at
<http://www.cl.cam.ac.uk/users/iwj10/debian-bugs/Reporting.html>
o On any Debian system with the doc-debian package installed. The
instructions are in the compressed (gzip'd) file
/usr/doc/debian/bug-reporting.txt.gz.
(Note that at the time of this writing, the files included in the doc-
debian package are not up to date with recent changes in the bug
tracking system.)
Use these mailing lists for bugs:
o submit@bugs.debian.org: for general bug reports. Expect to get an
automatic acknowledgement of your bug report. It will also be
automatically given a bug tracking number and entered into the Bug
log.
o maintonly@bugs.debian.org: to send bug reports to the maintainer
only. (It would otherwise be copied to the debian-devel mailing
list.) For example, if one were to identify a bug that was common
to many programs, then rather than entering dozens of bug reports,
one might prefer to send individual bugs to maintonly, then send a
summary report to debian-devel.
o quiet@bugs.debian.org: to submit bug reports to the list only,
without having them sent either to debian-devel or to the
maintainer.
14. Contributing to the Debian project
Donations of time (to develop new packages, maintain existing
packages, or provide user support), resources (to mirror the FTP and
WWW archives), and money (to pay for new testbeds as well as hardware
for the archives) can help the project.
14.1. How can I become a Debian software developer?
The development of the Debian distribution 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, and to provide user
support.
To develop a Debian package, you should:
o (of course) download the Debian distribution and install it on your
system.
o find a program you'd like to package that is not presently part of
Debian. In this regard, the Work Needing and Prospective Packages
document <ftp://www.debian.org/debian/doc/package-
developer/prospective-packages.txt> should serve as a useful guide.
o Subscribe to debian-devel.
To do this execute
mail debian-devel-REQUEST@lists.debian.org -s Subscribe
That is, send mail to the above address with the subject set to 'Sub-
scribe'.
o Set up your pgp key.
Install the PGP package; read /usr/doc/PGP; generate a public-
secret key pair by typing pgp -kg and answering the questions. (Be
prepared to write some arbitrary text when asked. PGP generates
its true random numbers by measuring the intervals between your
keystrokes.)
o Shake hands with the project administration, as it were:
Send emails to:
o The Project Leader. Bruce Perens
o The Administrator of master.debian.org: Simon Shapiro.
o The Mailing List Administrator: Anders Chigstrom.
o The dpkg maintainer: Ian Jackson.
i.e., To: bruce@pixar.com, shimon@i-connect.net, ac@netg.se,
ijackson@gnu.ai.mit.edu
with this content:
o what you've done,
o who you are,
o request for an account on master,
o request to be subscribed to debian-private (the developers-only
mailing list).
o your PGP key, obtained by executing 'pgp -kxa'.
o Make the programs: .deb, .diff, .tar.gz, .changes.
Use the hello*deb and dpkg*deb packages as guides, and read the
policy manual and dpkg programmers manual.
o Upload the files to
o ftp://master.debian.org/home/Debian/ftp/private/project/Incoming
using your user-name and password, or
o ftp://chiark.chu.cam.uc.uk/ using anonymous ftp.
For instructions to upload to chiark, read this file at chiark:
/pub/debian/private/project/README.how-to-upload. chiark then
sends the files it gets to master.
14.1.1. Are there additional information resources for developers?
Besides debian-devel, there are these mailing lists:
o The sparc port developers list: debian-sparc@lists.debian.org.
o The alpha port developers list: debian-alpha@lists.debian.org.
o The motorola 680xx port developers list:
debian-68k@lists.debian.org.
o The dpkg developemnt list: debian-dpkg@lists.debian.org.
o Debian for Hams: debian-hams@lists.debian.org.
o Debian package maintainers only: debian-private@lists.debian.org.
To subscribe to debian-devel, or other developers' list, send a
message to Anders Chigstrom (ac@netg.se) with a one-line explanation
of what you would like to test or develop.
14.2. 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 urgently
needed. It is desirable but not absolutely necessary to mirror all of
the archive. The current components amount to just over 1.1 GBytes,
broken down roughly as follows:
o binaries
o Debian-1.1 (including updates): 200 MBytes.
o non-free: 26 MBytes.
o contrib: 6 MBytes.
o rex: 216 MBytes.
o source code:
o Debian-1.1 (including updates): 235 MBytes.
o non-free: 23 MBytes.
o contrib: 3 MBytes.
o project/experimental: 13 MBytes.
o rex: 242 MBytes.
o project/experimental: 13 MBytes.
o bug log: 18 MBytes.
o mailing list archives: 42 MBytes.
o private/project/Incoming: 150 MBytes.
Most of the mirroring is accomplished entirely automatically by
scripts, without any human intervention. However, the occasional
glitch or system change occurs which requires real personnel
resources.
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 Bruce Perens (Email: bruce@pixar.com;
Voice (work): 510-215-3502).
14.3. How can I contribute financially to the Debian project?
One can make individual donations to one of two organizations that are
critical to the development of the Debian project.
14.3.1. Software in the Public Interest
Software in the Public Interest (SPI) is a non-profit organization
formed when FSF withdrew their sponsorship of Debian. We are
currently incorporating as an IRS 501(c)(3) non-profit organization.
The purpose of the organization is to develop and distribute free
software. Our goals are very much like those of FSF, and we encourage
programmers to use the GNU General Public License on their programs.
However, we have a slightly different focus in that we are building
and distributing a Linux system that diverges in many technical
details from the GNU system planned by FSF. We still communicate with
FSF, and we cooperate in sending them changes to GNU software and in
asking our users to donate to FSF and the GNU project.
SPI can be reached at:
o Email: bruce@pixar.com
o Postal address:
Software in the Public Interest
P.O. Box 70152
Pt. Richmond, CA 94807-0152
o Phone: 510-215-3502 (Bruce Perens at work)
14.3.2. Free Software Foundation
At this time there is no formal connection between Debian and the Free
Software Foundation. However, the Free Software Foundation is
responsible for some of the most important software components in
Debian, including the GNU C compiler, GNU Emacs, and much of the C
run-time library that is used by all programs on the system. FSF
pioneered much of what free software is today: they wrote the the
General Public License that is used on much of the Debian software,
and they invented the "GNU" project to create an entirely free Unix
system. Debian should be considered a descendent of the GNU system.
When you make a donation to FSF, please be sure to tell them that you
are a Debian user. Please contact them at:
o E-mail: gnu@prep.ai.mit.edu
o Postal address:
Free Software Foundation
59 Temple Place - Suite 330
Boston, MA 02111-1307
USA
o Phone number: +1-617-542-5942
o Fax (including Japan): +1-617-542-2652
o Free Dial Fax (in Japan): 0031-13-2473 (KDD), 0066-3382-0158 (IDC)
o On the WWW (unofficial FSF page): http://www.cs.pdx.edu/~trent/gnu/
15. Redistributing Debian Linux in a commercial product
15.1. Can I make and sell Debian CDs?
Go ahead. You don't need permission to distribute anything we've
released, so that you can master your CD as soon as the beta-test
ends. You don't have to pay us anything. We will, however, publish a
list of CD manufacturers who donate money, software, and time to the
Debian project, and we'll encourage users to buy from manufacturers
who donate, so it's good advertising to make donations. 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.
15.2. 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 aren't freely
redistributable. CD manufacturers may be able to distribute the
programs we've 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.
15.3. I'm making a special Linux distribution for a "vertical mar-
ket". Can I use Debian 1.1 for the guts of a Linux system and add my
own applications on top of it?
Yes. For example, one person is building a "Linux for Hams"
distribution, with specialized programs for Radio Amateurs. He's
starting with Debian 1.1 as the "base system", and adding programs to
control the transmitter, track satellites, etc. All of the programs he
adds are packaged with the Debian package system so that his users
will be able to upgrade easily when he releases subsequent CDs.
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
``diversions''; more details are given in the file
/usr/doc/debian/package-developers/diversions.txt.gz, which is part of
the doc-debian package.
15.4. 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.
16. What kind of changes should I expect to see in the next major
release of Debian Linux?
16.1. A New Approach to the Boot Floppies
In order to accomodate all of the hardware for which Linux drivers
have been written, yet still provide boot-floppies that can fit on a
5.25-inch disk, the Debian 1.2 distribution will provide a mechanism
to access all drivers that can be modularized as modules.
The default kernel has no IDE, no SCSI, little else. When the user
sets up the system, it builds a RAM disk image that is loaded at boot
time. The script on the RAM disk loads the modules for your local
hardware configuration _before_ it mounts the root. Some things that
still aren't modularized are in the default kernel.
The stripped-down kernel and the compressed installation root
filesystem fit on one 1200K floppy and run fine that way. The floppy
also contains a few of the most popular modules, and you get to feed
it more floppies (or a CD) containing other modules depending on your
configuration.
No-floppy bootstrap should be possible for systems with 8MB RAM and a
CD or DOS hard disk. One-floppy NFS bootstrap should be possible.
See /usr/src/linux/Documentation/initrd.txt .
16.2. New Debian package tools and documentation
Programmers' and Policy Manuals that provide detailed explanations of
the Debian package management system and approach are provided with
the new version of dpkg.
In addition, the new version of dpkg will include new tools for
automating the construction of Debian packages, and for supporting
multiple architechtures.
16.3. Increased security
Debian 1.2 will be equipped with the Shadow password suite of programs
and library routines which hide the plain text of the password file
from all users except root and provide for terminal access control,
and user and group administration. Shadow was written by John Haugh
II, and is available from the comp.sources.misc directory at any major
USENET archive - relevant files are in:
usenet/comp.sources.misc/volume38 and
usenet/comp.sources.misc/volume39.
Most of the relevant Debian utilities have been modified to make them
support shadow passwords. This includes the default login utility, as
well as vipw and vigr. The xdm X11 login utility and the adduser
script will be made shadow aware as well. In addition, there will be
minor changes to the shadow packages themselves.
In addition, the Linux library of Pluggable Authentication Modules (
<http://gluon.physics.ucla.edu/~morgan/pam>; a.k.a. libpam) that allow
sysadmins to choose authorization modes on an application-specific
basis will be available, and initially set to authenticate via shadow
password. It will initially be available for a small suite of
applications, but once fully deployed, it will be set up to support
additional methods of validation.