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8 Debian GNU/Linux Policy Manual.
9 Copyright (C)1996,1997,1998 Ian Jackson and Christian Schwarz;
10 released under the terms of the GNU
11 General Public License, version 2 or (at your option) any later.
12 Initial version 1996, Ian Jackson, ijackson@gnu.ai.mit.edu
13 Revised November 27, 1996, David A. Morris, bweaver@debian.org
14 New sections March 15, 1997, Christian Schwarz, schwarz@debian.org
15 Reworked/Restructured April-July 1997, Christian Schwarz, schwarz@debian.org
16 Maintainer since 1997, Christian Schwarz, schwarz@debian.org
17 Christoph Lameter contributed the "Web Standard"
18 The debian-policy mailing list has taken responsibility for the
19 contents of this document since September 1998, with the package
20 maintainers responsible for packaging administrivia only.
25 <title>Debian Policy Manual</title>
27 <name>Ian Jackson </name>
28 <email>ijackson@gnu.ai.mit.edu</email>
31 <name>Christian Schwarz</name>
32 <email>schwarz@debian.org</email>
35 <name>revised: David A. Morris</name>
36 <email>bweaver@debian.org</email>
39 <name>The Debian Policy mailing List</name>
40 <email>debian-policy@lists.debian.org</email>
42 <version>version &version;, &date;</version>
45 This manual describes the policy requirements for the Debian
46 GNU/Linux distribution. This includes the structure and
47 contents of the Debian archive and several design issues of the
48 operating system, as well as technical requirements that each
49 package must satisfy to be included in the distribution. The
50 policy package itself is maintained by a group of maintainers
51 that have no editorial powers. At the moment, the list of
55 <p>Michael Alan Dorman <email>mdorman@debian.org</email></p>
58 <p>Philip Hands <email>phil@hands.com</email></p>
61 <p>Julian Gilbey <email>jdg@debian.org</email></p>
64 <p>Manoj Srivastava <email>srivasta@debian.org</email></p>
72 Copyright ©1996,1997,1998 Ian Jackson
73 and Christian Schwarz.
76 This manual is free software; you may redistribute it and/or
77 modify it under the terms of the GNU General Public License
78 as published by the Free Software Foundation; either version
79 2, or (at your option) any later version.
83 This is distributed in the hope that it will be useful, but
84 <em>without any warranty</em>; without even the implied
85 warranty of merchantability or fitness for a particular
86 purpose. See the GNU General Public License for more
91 A copy of the GNU General Public License is available as
92 <tt>/usr/share/common-licenses/GPL</tt> in the Debian GNU/Linux
93 distribution or on the World Wide Web at
94 <url id="http://www.gnu.org/copyleft/gpl.html"
95 name="The GNU General Public Licence">. You can also obtain it by writing to the
96 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
97 Boston, MA 02111-1307, USA.
105 <heading>About this manual</heading>
107 <heading>Scope</heading>
109 This manual describes the policy requirements for the Debian
110 GNU/Linux distribution. This includes the structure and
111 contents of the Debian archive and several design issues of the
112 operating system, as well as technical requirements that
113 each package must satisfy to be included in the
119 This manual also describes Debian policy as it relates to
120 creating Debian packages. It is not a tutorial on how to build
121 packages, nor is it exhaustive where it comes to describing
122 the behavior of the packaging system. Instead, this manual
123 attempts to define the interface to the package management
124 system that the developers have to be conversant with.
127 Informally, the criteria used for inclusion is that the
128 material meet one of the following requirements:
130 <tag>Standard interfaces</tag>
133 The material presented represents an interface to
134 the packaging system that is mandated for use, and
135 is used by, a significant number of packages, and
136 therefore should not be changed without peer
137 review. Package maintainers can then rely on this
138 interfaces not changing, and the package
139 management software authors need to ensure
140 compatibility with these interface
141 definitions. (Control file and and changelog file
142 formats are examples.)
145 <tag>Chosen Convention</tag>
148 If there are a number of technically viable choices
149 that can be made, but one needs to select one of
150 these options for inter-operability. The version
151 number format is one example.
155 Please note that these are not mutually exclusive;
156 selected conventions often become parts of standard
163 The footnotes present in this manual are
164 merely informative, and are not part of Debian policy itself.
169 In this manual, the words <em>must</em>, <em>should</em> and
170 <em>may</em>, and the adjectives <em>required</em>,
171 <em>recommended</em> and <em>optional</em>, are used to
172 distinguish the significance of the various guidelines in
173 this policy document. Packages that do not conform the the
174 guidelines denoted by <em>must</em> (or <em>required</em>)
175 will generally not be considered acceptable for the Debian
176 distribution. Non-conformance with guidelines denoted by
177 <em>should</em> (or <em>recommended</em>) will generally be
178 considered a bug, but will not necessarily render a package
179 unsuitable for distribution. Guidelines denoted by
180 <em>may</em> (or <em>optional</em>) are truly optional and
181 adherence is left to the maintainer's discretion.
184 These classifications are roughly equivalent to the bug
185 severities <em>serious</em> (for <em>must</em> or
186 <em>required</em> directive violations), <em>minor</em>,
187 <em>normal</em> or <em>important</em>
188 (for <em>should</em> or <em>recommended</em> directive
189 violations) and <em>wishlist</em> (for <em>optional</em>
191 <p>Compare RFC 2119. Note, however, that these words are
192 used in a different way in this document.</p>
196 Much of the information presented in this manual will be
197 useful even when building a package which is to be
198 distributed in some other way or is intended for local use
203 <heading>New versions of this document</heading>
205 The current version of this document is always accessible from the
206 Debian FTP server <ftpsite>ftp.debian.org</ftpsite> as
207 <ftppath>/debian/doc/package-developer/debian-policy.html.tar.gz</ftppath>
209 <url id="http://www.debian.org/doc/debian-policy/"
210 name="Debian Policy Manual"> webpage.</p>
213 In addition, this manual is distributed via the Debian package
214 <tt>debian-policy</tt>.
218 The <tt>debian-policy</tt> package also includes the file
219 <tt>upgrading-checklist.txt</tt> which indicates policy
220 changes between versions of this document.
224 <heading>Feedback</heading>
227 As the Debian GNU/Linux system is continuously evolving this
231 While the authors of this document have tried hard to avoid
232 typos and other errors, these do still occur. If you discover
233 an error in this manual or if you want to give any
234 comments, suggestions, or criticisms please send an email to
235 the Debian Policy List,
236 <email>debian-policy@lists.debian.org</email>, or submit a
237 bug report against the <tt>debian-policy</tt> package.
242 <heading>The Debian Archive</heading>
244 The Debian GNU/Linux system is maintained and distributed as a
245 collection of <em>packages</em>. Since there are so many of
246 them (currently well over 6000), they are split into
247 <em>sections</em> and given <em>priorities</em> to simplify
248 the handling of them.
251 The effort of the Debian project is to build a free operating
252 system, but not every package we want to make accessible is
253 <em>free</em> in our sense (see the Debian Free Software
254 Guidelines, below), or may be imported/exported without
255 restrictions. Thus, the archive is split into the sections
256 <em>main</em>, <em>non-free</em>, <em>contrib</em>,
257 <em>non-US/main</em>, <em>non-US/non-free</em>, and
258 <em>non-US/contrib</em>. The sections are explained in detail
263 The <em>main</em> and the <em>non-US/main</em> sections
264 together form the <em>Debian GNU/Linux distribution</em>.
268 Packages in the other sections are not considered to be part
269 of the Debian distribution, although we support their use and
270 provide infrastructure for them (such as our bug-tracking
271 system and mailing lists). This Debian Policy Manual applies
272 to these packages as well.</p>
274 <sect id="pkgcopyright">
275 <heading>Package copyright and sections</heading>
277 The aims of this section are:
279 <list compact="compact">
281 <p>to allow us to make as much software available as we
285 <p>to allow us to encourage everyone to write free
289 <p>to allow us to make it easy for people to produce
290 CD-ROMs of our system without violating any licenses,
291 import/export restrictions, or any other laws.</p>
296 <heading>The Debian Free Software Guidelines</heading>
298 The Debian Free Software Guidelines (DFSG) form our
299 definition of `free software'. These are:
301 <tag>Free Redistribution
305 The license of a Debian component may not restrict any
306 party from selling or giving away the software as a
307 component of an aggregate software distribution
308 containing programs from several different
309 sources. The license may not require a royalty or
310 other fee for such sale.
317 The program must include source code, and must allow
318 distribution in source code as well as compiled form.
325 The license must allow modifications and derived
326 works, and must allow them to be distributed under the
327 same terms as the license of the original software.
330 <tag>Integrity of The Author's Source Code
334 The license may restrict source-code from being
335 distributed in modified form <em>only</em> if the
336 license allows the distribution of ``patch files''
337 with the source code for the purpose of modifying the
338 program at build time. The license must explicitly
339 permit distribution of software built from modified
340 source code. The license may require derived works to
341 carry a different name or version number from the
342 original software. (This is a compromise. The Debian
343 Project encourages all authors to not restrict any
344 files, source or binary, from being modified.)
347 <tag>No Discrimination Against Persons or Groups
351 The license must not discriminate against any person
355 <tag>No Discrimination Against Fields of Endeavor
359 The license must not restrict anyone from making use
360 of the program in a specific field of endeavor. For
361 example, it may not restrict the program from being
362 used in a business, or from being used for genetic
366 <tag>Distribution of License
370 The rights attached to the program must apply to all
371 to whom the program is redistributed without the need
372 for execution of an additional license by those
376 <tag>License Must Not Be Specific to Debian
380 The rights attached to the program must not depend on
381 the program's being part of a Debian system. If the
382 program is extracted from Debian and used or
383 distributed without Debian but otherwise within the
384 terms of the program's license, all parties to whom
385 the program is redistributed must have the same
386 rights as those that are granted in conjunction with
390 <tag>License Must Not Contaminate Other Software
394 The license must not place restrictions on other
395 software that is distributed along with the licensed
396 software. For example, the license must not insist
397 that all other programs distributed on the same medium
398 must be free software.
401 <tag>Example Licenses
405 The ``GPL,'' ``BSD,'' and ``Artistic'' licenses are
406 examples of licenses that we consider <em>free</em>.
413 <heading>The main section</heading>
415 Every package in <em>main</em> and <em>non-US/main</em>
416 must comply with the DFSG (Debian Free Software
420 In addition, the packages in <em>main</em>
421 <list compact="compact">
424 must not require a package outside of <em>main</em>
425 for compilation or execution (thus, the package must
426 not declare a "Depends", "Recommends", or
427 "Build-Depends" relationship on a non-<em>main</em>
433 must not be so buggy that we refuse to support them,
439 must meet all policy requirements presented in this
446 Similarly, the packages in <em>non-US/main</em>
447 <list compact="compact">
450 must not require a package outside of <em>main</em>
451 or <em>non-US/main</em> for compilation or
457 must not be so buggy that we refuse to support them,
462 must meet all policy requirements presented in this
470 <heading>The contrib section</heading>
472 Every package in <em>contrib</em> and
473 <em>non-US/contrib</em> must comply with the DFSG.
477 In addition, the packages in <em>contrib</em> and
478 <em>non-US/contrib</em>
479 <list compact="compact">
482 must not be so buggy that we refuse to support them,
488 must meet all policy requirements presented in this
496 Furthermore, packages in <em>contrib</em> must not require
497 a package in a <em>non-US</em> section for compilation or
502 Examples of packages which would be included in
503 <em>contrib</em> or <em>non-US/contrib</em> are:
504 <list compact="compact">
507 free packages which require <em>contrib</em>,
508 <em>non-free</em> packages or packages which are not
509 in our archive at all for compilation or execution,
515 wrapper packages or other sorts of free accessories for
523 <heading>The non-free section</heading>
525 Packages must be placed in <em>non-free</em> or
526 <em>non-US/non-free</em> if they are not compliant with
527 the DFSG or are encumbered by patents or other legal
528 issues that make their distribution problematic.
531 In addition, the packages in <em>non-free</em> and
532 <em>non-US/non-free</em>
533 <list compact="compact">
536 must not be so buggy that we refuse to support them,
542 must meet all policy requirements presented in this
543 manual that it is possible for them to meet.
546 It is possible that there are policy
547 requirements which the package is unable to
548 meet, for example, if the source is
549 unavailable. These situations will need to be
550 handled on a case-by-case basis.
560 <heading>The non-US sections</heading>
562 Some programs with cryptographic program code need to be
563 stored on the <em>non-US</em> server because of United
564 States export restrictions. Such programs must be
565 distributed in the appropriate <em>non-US</em> section,
566 either <em>non-US/main</em>, <em>non-US/contrib</em> or
567 <em>non-US/non-free</em>.
570 This applies only to packages which contain cryptographic
571 code. A package containing a program with an interface to
572 a cryptographic program or a program that's dynamically
573 linked against a cryptographic library should not be
574 distributed via the <em>non-US</em> server if it is
575 capable of running without the cryptographic library or
580 <heading>Further copyright considerations</heading>
582 Every package must be accompanied by a verbatim copy of
583 its copyright and distribution license in the file
584 <tt>/usr/share/doc/<ital><package-name></ital>/copyright</tt>
585 (see <ref id="copyrightfile"> for further details).
588 We reserve the right to restrict files from being included
589 anywhere in our archives if
590 <list compact="compact">
593 their use or distribution would break a law,
598 there is an ethical conflict in their distribution or
604 we would have to sign a license for them, or
609 their distribution would conflict with other project
617 Programs whose authors encourage the user to make
618 donations are fine for the main distribution, provided
619 that the authors do not claim that not donating is
620 immoral, unethical, illegal or something similar; in such
621 a case they must go in <em>non-free</em>.</p>
624 Packages whose copyright permission notices (or patent
625 problems) do not even allow redistribution of binaries
626 only, and where no special permission has been obtained,
627 must not be placed on the Debian FTP site and its mirrors
631 Note that under international copyright law (this applies
632 in the United States, too), <em>no</em> distribution or
633 modification of a work is allowed without an explicit
634 notice saying so. Therefore a program without a copyright
635 notice <em>is</em> copyrighted and you may not do anything
636 to it without risking being sued! Likewise if a program
637 has a copyright notice but no statement saying what is
638 permitted then nothing is permitted.</p>
641 Many authors are unaware of the problems that restrictive
642 copyrights (or lack of copyright notices) can cause for
643 the users of their supposedly-free software. It is often
644 worthwhile contacting such authors diplomatically to ask
645 them to modify their license terms. However, this can be a
646 politically difficult thing to do and you should ask for
647 advice on the <tt>debian-legal</tt> mailing list first, as
652 When in doubt about a copyright, send mail to
653 <email>debian-legal@lists.debian.org</email>. Be prepared
654 to provide us with the copyright statement. Software
655 covered by the GPL, public domain software and BSD-like
656 copyrights are safe; be wary of the phrases `commercial
657 use prohibited' and `distribution restricted'.
661 <heading>Subsections</heading>
664 The packages in the sections <em>main</em>,
665 <em>contrib</em> and <em>non-free</em> are grouped further
666 into <em>subsections</em> to simplify handling.
670 The section and subsection for each package should be
671 specified in the package's <tt>Section</tt> control
672 record. However, the maintainer of the Debian archive
673 may override this selection to ensure the consistency of
674 the Debian distribution. The <tt>Section</tt> field
675 should be of the form:
676 <list compact="compact">
679 <ital>subsection</ital> if the package is in the
680 <em>main</em> section,
685 <ital>section/subsection</ital> if the package is in
686 the <em>contrib</em> or <em>non-free</em> section,
692 <tt>non-US</tt>, <tt>non-US/contrib</tt> or
693 <tt>non-US/non-free</tt> if the package is in
694 <em>non-US/main</em>, <em>non-US/contrib</em> or
695 <em>non-US/non-free</em> respectively.
702 The Debian archive maintainers provide the authoritative
703 list of subsections. At present, they are:
704 <em>admin</em>, <em>base</em>, <em>comm</em>,
705 <em>contrib</em>, <em>devel</em>, <em>doc</em>,
706 <em>editors</em>, <em>electronics</em>, <em>games</em>,
707 <em>graphics</em>, <em>hamradio</em>,
708 <em>interpreters</em>, <em>libs</em>, <em>mail</em>,
709 <em>math</em>, <em>misc</em>, <em>net</em>, <em>news</em>,
710 <em>non-US</em>, <em>non-free</em>, <em>oldlibs</em>,
711 <em>otherosfs</em>, <em>science</em>, <em>shells</em>,
712 <em>sound</em>, <em>tex</em>, <em>text</em>,
713 <em>utils</em>, <em>web</em>, <em>x11</em>.
717 <heading>Priorities</heading>
720 Each package should have a <em>priority</em> value, which is
721 included in the package's <em>control record</em>. This
722 information is used by the Debian package management tools
723 to separate high-priority packages from less-important
727 The following <em>priority levels</em> are recognised by the
728 Debian package management tools.
730 <tag><tt>required</tt></tag>
733 Packages which are necessary for the proper
734 functioning of the system. You must not remove these
735 packages or your system may become totally broken and
736 you may not even be able to use <prgn>dpkg</prgn> to
737 put things back. Systems with only the
738 <tt>required</tt> packages are probably unusable, but
739 they do have enough functionality to allow the
740 sysadmin to boot and install more software.</p>
742 <tag><tt>important</tt></tag>
745 Important programs, including those which one would
746 expect to find on any Unix-like system. If the
747 expectation is that an experienced Unix person who
748 found it missing would say `What on earth is going on,
749 where is <prgn>foo</prgn>?', it must be an
750 <tt>important</tt> package.
753 This is an important criterion because we are
754 trying to produce, amongst other things, a free
758 Other packages without which the system will not run
759 well or be usable must also have priority
760 <tt>important</tt>. This does
761 <em>not</em> include Emacs, the X Window System, TeX
762 or any other large applications. The
763 <tt>important</tt> packages are just a bare minimum of
764 commonly-expected and necessary tools.</p>
766 <tag><tt>standard</tt></tag>
769 These packages provide a reasonably small but not too
770 limited character-mode system. This is what will
771 install by default if the user doesn't select anything
772 else. It doesn't include many large applications, but
773 it does include Emacs (this is more of a piece of
774 infrastructure than an application) and a reasonable
775 subset of TeX and LaTeX.</p>
777 <tag><tt>optional</tt></tag>
780 (In a sense everything that isn't required is
781 optional, but that's not what is meant here.) This is
782 all the software that you might reasonably want to
783 install if you didn't know what it was and don't have
784 specialized requirements. This is a much larger system
785 and includes the X Window System, a full TeX
786 distribution, and many applications. Note that
787 optional packages should not conflict with each other.
790 <tag><tt>extra</tt></tag>
793 This contains all packages that conflict with others
794 with required, important, standard or optional
795 priorities, or are only likely to be useful if you
796 already know what they are or have specialised
803 Packages must not depend on packages with lower priority
804 values (excluding build-time dependencies). In order to
805 ensure this, the priorities of one or more packages may need
811 <heading>Binary packages</heading>
814 The Debian GNU/Linux distribution is based on the Debian
815 package management system, called <prgn>dpkg</prgn>. Thus,
816 all packages in the Debian distribution must be provided
817 in the <tt>.deb</tt> file format.</p>
821 <heading>The package name</heading>
824 Every package must have a name that's unique within the Debian
828 Package names must only consist of lower case letters, digits (0-9),
829 plus (+) or minus (-) signs, and periods (.).</p>
832 The package name is part of the file name of the
833 <tt>.deb</tt> file and is included in the control field
839 <heading>The maintainer of a package</heading>
841 Every package must have a maintainer (the maintainer may
842 be one person or a group of people reachable from a common
843 email address, such as a mailing list). The maintainer is
844 responsible for ensuring that the package is placed in
845 the appropriate distribution
849 The maintainer must be specified in the
850 <tt>Maintainer</tt> control field with the correct name
851 and a working email address for the Debian maintainer of
852 the package. If one person maintains several packages
853 he/she should try to avoid having different forms of their
854 name and email address in different <tt>Maintainer</tt>
858 If the maintainer of a package quits from the Debian
859 project the Debian QA Group
860 <email>debian-qa@lists.debian.org</email> takes over the
861 maintainership of the package until someone else
862 volunteers for that task. These packages are called
863 <em>orphaned packages</em>.
869 <heading>The description of a package</heading>
872 Every Debian package must have an extended description
873 stored in the appropriate field of the control record.</p>
876 The description should be written so that it tells the user
877 what they need to know to decide whether to install the
878 package. This description should not just be copied from
879 the blurb for the program. Instructions for configuring
880 or using the package should not be included -- that is what
881 installation scripts, manual pages, Info files, etc. are
882 for. Copyright statements and other administrivia should
883 not be included -- that is what the copyright file is
889 <heading>Dependencies</heading>
892 Every package must specify the dependency information
893 about other packages that are required for the first to
897 For example, a dependency entry must be provided for any
898 shared libraries required by a dynamically-linked executable
899 binary in a package.</p>
902 Packages are not required to declare any dependencies they
903 have on other packages which are marked <tt>Essential</tt>
904 (see below), and should not do so unless they depend on a
905 particular version of that package.</p>
908 Sometimes, a package requires another package to be installed
909 <em>and</em> configured before it can be installed. In this
910 case, you must specify a <tt>Pre-Depends</tt> entry for
914 You should not specify a <tt>Pre-Depends</tt> entry for a
915 package before this has been discussed on the
916 <tt>debian-devel</tt> mailing list and a consensus about
917 doing that has been reached.</p></sect1>
921 <heading>Virtual packages</heading>
924 Sometimes, there are several packages doing more-or-less
925 the same job. In this case, it's useful to define a
926 <em>virtual package</em> whose name describes the function
927 the packages have. (The virtual packages just exist
928 logically, not physically--that's why they are called
929 <em>virtual</em>.) The packages with this particular
930 function will then <em>provide</em> the virtual
931 package. Thus, any other package requiring that function
932 can simply depend on the virtual package without having to
933 specify all possible packages individually.</p>
936 All packages should use virtual package names where
937 appropriate, and arrange to create new ones if necessary.
938 They should not use virtual package names (except privately,
939 amongst a cooperating group of packages) unless they have
940 been agreed upon and appear in the list of virtual package
944 The latest version of the authoritative list of virtual
945 package names can be found on
946 <ftpsite>ftp.debian.org</ftpsite> in
947 <ftppath>/debian/doc/package-developer/virtual-package-names-list.text</ftppath>
948 or your local mirror. In addition, it is included in the
949 <tt>debian-policy</tt> package. The procedure for updating
950 the list is described at the top of the file.</p></sect1>
954 <heading>Base packages</heading>
957 The packages included in the <tt>base</tt> section have a
958 special function. They form a minimum subset of the Debian
959 GNU/Linux system that is installed before everything else
960 on a new system. Thus, only very few packages are allowed
961 to go into the <tt>base</tt> section to keep the required
962 disk usage very small.</p>
965 Most of these packages will have the priority value
966 <tt>required</tt> or at least <tt>important</tt>, and many
967 of them will be tagged <tt>essential</tt> (see below).</p>
970 You must not place any packages into the <tt>base</tt>
971 section before this has been discussed on the
972 <tt>debian-devel</tt> mailing list and a consensus about
973 doing that has been reached.</p></sect1>
977 <heading>Essential packages</heading>
980 Some packages are tagged <tt>essential</tt>. (They have
981 <tt>Essential: yes</tt> in their package control record.)
982 This flag is used for packages that are <em>essential</em>
986 Since these packages can not easily be removed (you'll
987 have to specify an extra <em>force option</em> to
988 <prgn>dpkg</prgn>) this flag must not be used unless
989 absolutely necessary. A shared library package must not
990 be tagged <tt>essential</tt>--the dependencies will
991 prevent its premature removal, and we need to be able to
992 remove it when it has been superseded.
996 Since dpkg will not prevent upgrading of other packages
997 while an <tt>essential</tt> package is in an unconfigured
998 state, all <tt>essential</tt> packages must supply all
999 their core functionality even when unconfigured. If the
1000 package cannot satisfy this requirement it must not be
1001 tagged as essential, and any packages depending on this
1002 package must instead have explicit dependency fields as
1007 You must not tag any packages <tt>essential</tt> before
1008 this has been discussed on the <tt>debian-devel</tt>
1009 mailing and a consensus about doing that has been
1010 reached.</p></sect1>
1014 <heading>Maintainer scripts</heading>
1017 The package installation scripts should avoid producing
1018 output which it is unnecessary for the user to see and
1019 should rely on <prgn>dpkg</prgn> to stave off boredom on
1020 the part of a user installing many packages. This means,
1021 amongst other things, using the <tt>--quiet</tt> option on
1022 <prgn>install-info</prgn>.</p>
1025 Errors which occur during the execution of an installation
1026 script must be checked and the installation must not
1027 continue after an error.
1031 Note, that <ref id="scripts">, in general applies to package
1032 maintainer scripts, too.
1036 You should not use <tt>dpkg-divert</tt> on a file
1037 belonging to another package without consulting the
1038 maintainer of that package first.
1041 All packages which supply an instance of a common command
1042 name (or, in general, filename) should generally use
1043 <prgn>update-alternatives</prgn>, so that they may be
1044 installed together. If <prgn>update-alternatives</prgn>
1045 is not used, then each package must use
1046 <var>Conflicts</var> to ensure that other packages are
1047 de-installed. (In this case, it may be appropriate to
1048 specify a conflict against earlier versions of something
1049 that previously did not use
1050 <prgn>update-alternatives</prgn> - this is an exception to
1051 the usual rule that this not allowed).
1056 <heading>Prompting in maintainer scripts</heading>
1058 Package maintainer scripts may prompt the user if
1059 necessary. Prompting may be accomplished by hand, or by
1060 communicating with a program, such as
1061 <prgn>debconf</prgn>, which conforms to the Debian
1062 Configuration management specification, version 2 or
1063 higher. (Included in the
1064 <file>debconf_specification</file> files in the
1065 <package>debian-policy</package> package.)
1066 You may also find this file on the FTP site
1067 <ftpsite>ftp.debian.org</ftpsite> in
1068 <ftppath>/debian/doc/package-developer/debconf_specification.txt.gz</ftppath>
1069 or your local mirror.
1072 2.5% of Debian packages
1073 [<url id="http://kitenet.net/programs/debconf/stats/">]
1074 use debconf to prompt the user at install time, and
1075 this number is growing daily. The benefits of using
1076 debconf are briefly explained at
1077 <url id="http://kitenet.net/doc/debconf-doc/introduction.html">;
1078 they include preconfiguration, (mostly)
1079 noninteractive installation, elimination of
1080 redundant prompting, consistency of user interface,
1084 With this increasing number of packages using
1085 debconf, plus the existance of a nascent second
1086 implementation of the Debian configuration
1087 management system (<package>cdebconf</package>), and
1088 the stabalization of the protocol these things use,
1089 the time has finally come to reflect the use of
1090 these things in policy.
1096 Packages which use the Debian Configuration management
1097 specification may contain an additional
1098 <file>config</file> script and a <file>templates</file>
1099 file in their control archive. The <prgn>config</prgn>
1100 script can be run before the preinst, and before the
1101 package is unpacked or any of its dependancies or
1102 pre-dependancies are satisfied, so it must work using
1103 only the tools present in the <em>Essential</em>
1107 Debconf or another tool that implements the Debian
1108 Configuration management specification will also be
1109 installed, and any versioned dependancies on it will
1110 be satisfied before preconfiguration begins.
1116 Packages should try to minimize the amount of prompting
1117 they need to do, and they should ensure that the user
1118 will only ever be asked each question once. This means
1119 that packages should try to use appropriate shared
1120 configuration files (such as <tt>/etc/papersize</tt> and
1121 <tt>/etc/news/server</tt>), and shared debconf variables
1122 rather than each prompting for their own list of
1123 required pieces of information.
1127 It also means that an upgrade should not ask the same
1128 questions again, unless the user has used <tt>dpkg
1129 --purge</tt> to remove the package's configuration. The
1130 answers to configuration questions should be stored in an
1131 appropriate place in <tt>/etc</tt> so that the user can
1132 modify them, and how this has been done should be
1136 If a package has a vitally important piece of
1137 information to pass to the user (such as "don't run me
1138 as I am, you must edit the following configuration files
1139 first or you risk your system emitting badly-formatted
1140 messages"), it should display this in the
1141 <prgn>config</prgn> or <prgn>postinst</prgn> script and
1142 prompt the user to hit return to acknowledge the
1143 message. Copyright messages do not count as vitally
1144 important (they belong in
1145 <tt>/usr/share/doc/<var>package</var>/copyright</tt>);
1146 neither do instructions on how to use a program (these
1147 should be in on line documentation, where all the users
1151 Any necessary prompting should almost always be confined
1152 to the <prgn>config</prgn> or <prgn>postinst</prgn>
1153 script. If it is done in the <prgn>postinst</prgn>, it
1154 should be protected with a conditional so that unnecessary
1155 prompting doesn't happen if a package's installation fails
1156 and the <prgn>postinst</prgn> is called with
1157 <tt>abort-upgrade</tt>, <tt>abort-remove</tt> or
1158 <tt>abort-deconfigure</tt>.</p>
1163 <heading>Source packages</heading>
1166 <heading>Standards conformance</heading>
1169 You should specify the most recent version of the
1170 packaging standards with which your package complies in
1171 the source package's <tt>Standards-Version</tt> field.</p>
1174 This value will be used to file bug reports automatically
1175 if your package becomes too much out of date.</p>
1178 The value corresponds to a version of the Debian manuals,
1179 as can be found on the title page or page headers and
1180 footers (depending on the format).</p>
1183 The version number has four components--major and minor
1184 number and major and minor patch level. When the
1185 standards change in a way that requires every package to
1186 change the major number will be changed. Significant
1187 changes that will require work in many packages will be
1188 signaled by a change to the minor number. The major patch
1189 level will be changed for any change to the meaning of the
1190 standards, however small; the minor patch level will be
1191 changed when only cosmetic, typographical or other edits
1192 which do not change the meaning are made, or changes which
1193 do not affect the contents of packages.</p>
1196 For package maintainers, only the first 3 digits of the
1197 manual version are significant in representing the
1198 <em>Standards-Version</em>, and either these 3 digits or
1199 the complete 4 digits may be specified.
1202 In the past, people specified 4 digits in the
1203 Standards-Version field, like `2.3.0.0'. Since any
1204 `patch-level changes' don't introduce new policy, it
1205 was thought it would be better to relax policy and
1206 only require that the first 3 digits are specified. (4
1207 digits may still be used if someone wants to do so.)
1213 You should regularly, and especially if your package has
1214 become out of date, check for the newest Policy Manual
1215 available and update your package, if necessary. When your
1216 package complies with the new standards you should update the
1217 <tt>Standards-Version</tt> source package field and
1218 release it.</p></sect1>
1222 <heading>Package relationships</heading>
1225 Source packages should specify which binary packages they
1226 require to be installed or not to be installed in order to
1227 build correctly. For example, if building a package
1228 requires a certain compiler, then the compiler should be
1229 specified as a build-time dependency.
1233 It is not necessary to explicitly specify build-time
1234 relationships on a minimal set of packages that are always
1235 needed to compile, link and put in a Debian package a
1236 standard "Hello World!" program written in C or C++. The
1237 required packages are called <em>build-essential</em>, and
1238 an informational list can be found in
1239 <tt>/usr/share/doc/build-essential/list</tt> (which is
1240 contained in the <tt>build-essential</tt>
1246 <p>This allows maintaining the list separately
1247 from the policy documents (the list does not
1248 need the kind of control that the policy
1254 Having a separate package allows one to install
1255 the build essential packages on a machine, as
1256 well as allowing other packages (think task
1257 packages) to bring in the build-essential
1258 packages using the depends relation
1263 The separate package allows bug reports against
1264 the package to be categorized separately from
1265 the policy management process that uses the BTS
1275 When specifying the set of build-time dependencies, one
1276 should list only those packages explicitly required by the
1277 build. It is not necessary to list packages which are
1278 required merely because some other package in the list of
1279 build-time dependencies depends on them. The reason is
1280 that dependencies change, and you should list only those
1281 <em>you</em> need. What others need is their business.
1285 If build-time dependencies are specified, it must be
1286 possible to build the package and produce working binaries
1287 on a system with the build-essential packages installed
1288 and satisfying the build-time relationships (including any
1289 implied relationships). This
1290 means in particular that version clauses should be used
1291 rigorously in build-time relationships so that one cannot
1292 produce bad or inconsistently configured packages when the
1293 relationships are properly satisfied.
1297 <heading>Changes to the upstream sources</heading>
1300 If changes to the source code are made that are generally
1301 applicable, they should be sent to the upstream authors
1302 in whatever form they prefer so as to be included in the
1303 upstream version of the package.</p>
1306 If you need to configure the package differently for
1307 Debian or for Linux, and the upstream source doesn't
1308 provide a way to configure it the way you need to, you
1309 should add such configuration facilities (for example, a new
1310 <prgn>autoconf</prgn> test or <tt>#define</tt>) and send
1311 the patch to the upstream authors, with the default set to
1312 the way they originally had it. You can then easily
1313 override the default in your <tt>debian/rules</tt> or
1314 wherever is appropriate.</p>
1317 You should make sure that the <prgn>configure</prgn> utility
1318 detects the correct architecture specification string
1319 (refer to <ref id="arch-spec"> for details).</p>
1322 If you need to edit a <prgn>Makefile</prgn> where
1323 GNU-style <prgn>configure</prgn> scripts are used, you
1324 should edit the <tt>.in</tt> files rather than editing the
1325 <prgn>Makefile</prgn> directly. This allows the user to
1326 reconfigure the package if necessary. You should
1327 <em>not</em> configure the package and edit the generated
1328 <prgn>Makefile</prgn>! This makes it impossible for
1329 someone else to later reconfigure the package.</p></sect1>
1333 <heading>Documenting your changes</heading>
1336 You should document your changes and updates to the source
1337 package properly in the <tt>debian/changelog</tt> file. (Note
1338 that mistakes in changelogs are usually best rectified by
1339 making a new changelog entry rather than "rewriting history"
1340 by editing old changelog entries)</p>
1343 In non-experimental packages you must only use a format for
1344 <tt>debian/changelog</tt> which is supported by the most
1345 recent released version of <prgn>dpkg</prgn>. If your
1346 format is not supported and there is general support for
1347 it you should contact the <prgn>dpkg</prgn> maintainer to
1348 have the parser script for your format included in the
1349 <prgn>dpkg</prgn> package. (You will need to agree that
1350 the parser and its manpage may be distributed under the
1351 GNU GPL, just as the rest of <prgn>dpkg</prgn>
1356 <heading>Error trapping in makefiles</heading>
1359 When <prgn>make</prgn> invokes a command in a makefile
1360 (including your package's upstream makefiles and the
1361 <tt>debian/rules</tt>) it does so using <tt>sh</tt>. This
1362 means that <tt>sh</tt>'s usual bad error handling
1363 properties apply: if you include a miniature script as one
1364 of the commands in your makefile you'll find that if you
1365 don't do anything about it then errors are not detected
1366 and <prgn>make</prgn> will blithely continue after
1370 Every time you put more than one shell command (this
1371 includes using a loop) in a makefile command you
1372 must make sure that errors are trapped. For
1373 simple compound commands, such as changing directory and
1374 then running a program, using <tt>&&</tt> rather
1375 than semicolon as a command separator is sufficient. For
1376 more complex commands including most loops and
1377 conditionals you should include a separate <tt>set -e</tt>
1378 command at the start of every makefile command that's
1379 actually one of these miniature shell scripts.</p></sect1>
1383 <heading>Obsolete constructs and libraries</heading>
1386 The include file <prgn><varargs.h></prgn> is
1387 provided to support end-users compiling very old software;
1388 the library <tt>libtermcap</tt> is provided to support the
1389 execution of software which has been linked against it
1390 (either old programs or those such as Netscape which are
1391 only available in binary form).</p>
1394 Debian packages should be ported to include
1395 <prgn><stdarg.h></prgn> and <tt>ncurses</tt> when
1401 <chapt id="controlfields"><heading>Control files and their fields</heading>
1404 Many of the tools in the package management suite manipulate
1405 data in a common format, known as control files. Binary and
1406 source packages have control data as do the <tt>.changes</tt>
1407 files which control the installation of uploaded files, and
1408 <prgn>dpkg</prgn>'s internal databases are in a similar
1412 <sect><heading>Syntax of control files</heading>
1415 A file consists of one or more paragraphs of fields. The
1416 paragraphs are separated by blank lines. Some control files
1417 only allow one paragraph; others allow several, in which
1418 case each paragraph often refers to a different package.
1422 Each paragraph is a series of fields and values; each field
1423 consists of a name, followed by a colon and the value. It
1424 ends at the end of the line. Horizontal whitespace (spaces
1425 and tabs) may occur immediately before or after the value
1426 and is ignored there; it is conventional to put a single
1427 space after the colon.
1431 Some fields' values may span several lines; in this case
1432 each continuation line <em>must</em> start with a space or
1433 tab. Any trailing spaces or tabs at the end of individual
1434 lines of a field value are ignored.
1438 Except where otherwise stated only a single line of data is
1439 allowed and whitespace is not significant in a field body.
1440 Whitespace may never appear inside names (of packages,
1441 architectures, files or anything else), version numbers or
1442 in between the characters of multi-character version
1447 Field names are not case-sensitive, but it is usual to
1448 capitalize the field names using mixed case as shown below.
1452 Blank lines, or lines consisting only of spaces and tabs,
1453 are not allowed within field values or between fields - that
1454 would mean a new paragraph.
1458 It is important to note that there are several fields which
1459 are optional as far as <prgn>dpkg</prgn> and the related
1460 tools are concerned, but which must appear in every Debian
1461 package, or whose omission may cause problems. When writing
1462 the control files for Debian packages you <em>must</em> read
1463 the Debian policy manual in conjunction with the details
1464 below and the list of fields for the particular file.</p>
1467 <sect><heading>List of fields</heading>
1469 This list here is not supposed to be exhaustive. Most fields
1470 are dealt with elsewhere in this document and in the
1473 <sect1 id="f-Package"><heading><tt>Package</tt>
1477 The name of the binary package. Package names consist of
1478 the alphanumerics and <tt>+</tt> <tt>-</tt> <tt>.</tt>
1479 (plus, minus and full stop).
1483 They must be at least two characters long and must start
1484 with an alphanumeric character. The use of lowercase
1485 package names is strongly recommended unless the package
1486 you're building (or referring to, in other fields) is
1487 already using uppercase.</p>
1490 <sect1 id="f-Version"><heading><tt>Version</tt>
1494 This lists the source or binary package's version number -
1495 see <ref id="versions">.
1501 id="f-Standards-Version"><heading><tt>Standards-Version</tt>
1505 The most recent version of the standards (the policy
1506 manual and associated texts) with which the package
1507 complies. This is updated manually when editing the
1508 source package to conform to newer standards; it can
1509 sometimes be used to tell when a package needs attention.
1513 Its format is the same as that of a version number except
1514 that no epoch or Debian revision is allowed - see <ref
1519 <sect1 id="f-Distribution"><heading><tt>Distribution</tt>
1523 In a <tt>.changes</tt> file or parsed changelog output
1524 this contains the (space-separated) name(s) of the
1525 distribution(s) where this version of the package should
1526 be or was installed. Distribution names follow the rules
1527 for package names. (See <ref id="f-Package">).
1532 Current distribution values are:
1534 <tag><em>stable</em></tag>
1537 This is the current `released' version of Debian
1539 distribution is <em>stable</em> only major bug fixes
1540 are allowed. When changes are made to this
1541 distribution, the release number is increased
1542 (for example: 1.2r1 becomes 1.2r2 then 1.2r3, etc).
1546 <tag><em>unstable</em></tag>
1549 This distribution value refers to the
1550 <em>developmental</em> part of the Debian
1551 distribution tree. New packages, new upstream
1552 versions of packages and bug fixes go into the
1553 <em>unstable</em> directory tree. Download from
1554 this distribution at your own risk.
1558 <tag><em>frozen</em></tag>
1561 From time to time, the <em>unstable</em>
1562 distribution enters a state of `code-freeze' in
1563 anticipation of release as a <em>stable</em>
1564 version. During this period of testing only
1565 fixes for existing or newly-discovered bugs will
1570 <tag><em>experimental</em></tag>
1573 The packages with this distribution value are deemed
1574 by their maintainers to be high risk. Oftentimes they
1575 represent early beta or developmental packages from
1576 various sources that the maintainers want people to
1577 try, but are not ready to be a part of the other parts
1578 of the Debian distribution tree. Download at your own
1583 There are several sections in each
1584 distribution. Currently, these sections are:
1587 <tag><em>main</em></tag>
1590 The packages in this section are those in the
1591 main Debian distribution. They are all free
1592 (according to the Debian free software
1593 guidelines) and meet any other criteria for
1594 inclusion described in this manual.</p>
1597 <tag><em>contrib</em></tag>
1600 The packages in this section do not meet the
1601 criteria for inclusion in the main Debian
1602 distribution as defined by this manual, but are
1603 otherwise free, as defined by the Debian free
1604 software guidelines.</p>
1607 <tag><em>non-free</em></tag>
1610 Packages in <em>non-free</em> do not meet the
1611 criteria of free software, as defined by the
1612 Debian free software guidelines. Again, use your
1613 best judgment in downloading from this
1617 </taglist> You should list <em>all</em> distributions that
1618 the package should be installed into. Except in unusual
1619 circumstances, installations to <em>stable</em> should also
1620 go into <em>frozen</em> (if it exists) and
1621 <em>unstable</em>. Likewise, installations into
1622 <em>frozen</em> should also go into <em>unstable</em>.
1631 <chapt id="versions"><heading>Version numbering </heading>
1634 Every package has a version number, in its <tt>Version</tt>
1639 The package management system imposes an ordering on version
1640 numbers, so that it can tell whether packages are being up- or
1641 downgraded and so that package system front end applications
1642 can tell whether a package it finds available is newer than
1643 the one installed on the system. The version number format
1644 has the most significant parts (as far as comparison is
1645 concerned) at the beginning.
1649 The version number format is:
1650 &lsqb<var>epoch</var><tt>:</tt>]<var>upstream-version</var>[<tt>-</tt><var>debian-revision</var>]
1654 The three components here are:
1656 <tag><var>epoch</var></tag>
1660 This is a single (generally small) unsigned integer. It
1661 may be omitted, in which case zero is assumed. If it is
1662 omitted then the <var>upstream-version</var> may not
1667 It is provided to allow mistakes in the version numbers
1668 of older versions of a package, and also a package's
1669 previous version numbering schemes, to be left behind.
1674 <tag><var>upstream-version</var></tag>
1678 This is the main part of the version. It is usually the
1679 version number of the original (`upstream') package from
1680 which the <tt>.deb</tt> file has been made, if this is
1681 applicable. Usually this will be in the same format as
1682 that specified by the upstream author(s); however, it
1683 may need to be reformatted to fit into the package
1684 management system's format and comparison scheme.
1688 The comparison behavior of the package management system
1689 with respect to the <var>upstream-version</var> is
1690 described below. The <var>upstream-version</var>
1691 portion of the version number is mandatory.
1695 The <var>upstream-version</var> may contain only
1696 alphanumerics and the characters <tt>.</tt> <tt>+</tt>
1697 <tt>-</tt> <tt>:</tt> (full stop, plus, hyphen, colon)
1698 and should start with a digit. If there is no
1699 <var>debian-revision</var> then hyphens are not allowed;
1700 if there is no <var>epoch</var> then colons are not
1704 <tag><var>debian-revision</var></tag>
1708 This part of the version represents the version of the
1709 modifications that were made to the package to make it a
1710 Debian binary package. It is in the same format as the
1711 <var>upstream-version</var> and is compared in the same
1716 It is optional; if it isn't present then the
1717 <var>upstream-version</var> may not contain a hyphen.
1718 This format represents the case where a piece of
1719 software was written specifically to be turned into a
1720 Debian binary package, and so there is only one
1721 `debianization' of it and therefore no revision
1722 indication is required.
1726 It is conventional to restart the
1727 <var>debian-revision</var> at <tt>1</tt> each time the
1728 <var>upstream-version</var> is increased.
1732 The package management system will break the
1733 <var>upstream-version</var> and
1734 <var>debian-revision</var> apart at the last hyphen in
1735 the string. The absence of a <var>debian-revision</var>
1736 compares earlier than the presence of one (but note that
1737 the <var>debian-revision</var> is the least significant
1738 part of the version number).
1742 The <var>debian-revision</var> may contain only
1743 alphanumerics and the characters <tt>+</tt> and
1744 <tt>.</tt> (plus and full stop).
1748 The <var>upstream-version</var> and <var>debian-revision</var>
1749 parts are compared by the package management system using the
1754 The strings are compared from left to right.
1758 First the initial part of each string consisting entirely of
1759 non-digit characters is determined. These two parts (one of
1760 which may be empty) are compared lexically. If a difference
1761 is found it is returned. The lexical comparison is a
1762 comparison of ASCII values modified so that all the letters
1763 sort earlier than all the non-letters.
1767 Then the initial part of the remainder of each string which
1768 consists entirely of digit characters is determined. The
1769 numerical values of these two parts are compared, and any
1770 difference found is returned as the result of the comparison.
1771 For these purposes an empty string (which can only occur at
1772 the end of one or both version strings being compared) counts
1777 These two steps are repeated (chopping initial non-digit
1778 strings and initial digit strings off from the start) until a
1779 difference is found or both strings are exhausted.
1783 Note that the purpose of epochs is to allow us to leave behind
1784 mistakes in version numbering, and to cope with situations
1785 where the version numbering changes. It is <em>not</em> there
1786 to cope with version numbers containing strings of letters
1787 which the package management system cannot interpret (such as
1788 <tt>ALPHA</tt> or <tt>pre-</tt>), or with silly orderings (the
1789 author of this manual has heard of a package whose versions
1790 went <tt>1.1</tt>, <tt>1.2</tt>, <tt>1.3</tt>, <tt>1</tt>,
1791 <tt>2.1</tt>, <tt>2.2</tt>, <tt>2</tt> and so forth).
1795 If an upstream package has problematic version numbers they
1796 should be converted to a sane form for use in the
1797 <tt>Version</tt> field.
1801 <heading>Version numbers based on dates</heading>
1803 In general, Debian packages should use the same version
1804 numbers as the upstream sources.</p>
1807 However, in some cases where the upstream version number is
1808 based on a date (e.g., a development `snapshot' release) the
1809 package management system cannot handle these version
1810 numbers without epochs. For example, dpkg will consider
1811 `96May01' to be greater than `96Dec24'.</p>
1814 To prevent having to use epochs for every new upstream
1815 version, the version number should be changed to the
1816 following format in such cases: `19960501', `19961224'. It
1817 is up to the maintainer whether he/she wants to bother the
1818 upstream maintainer to change the version numbers upstream,
1822 Note, that other version formats based on dates which are
1823 parsed correctly by the package management system should
1824 <em>not</em> be changed.</p>
1827 Native Debian packages (i.e., packages which have been
1828 written especially for Debian) whose version numbers include
1829 dates should always use the `YYYYMMDD' format.</p>
1833 <chapt id="miscellaneous"><heading>Packaging Considerations</heading>
1835 <sect id="timestamps"><heading>Time Stamps</heading>
1837 Maintainers are encouraged to preserve the modification
1838 times of the upstream source files in a package, as far as
1839 is reasonably possible. Even though this is optional, this
1840 is still a good idea.
1843 The rationale is that there is some information conveyed
1844 by knowing the age of the file, for example, you could
1845 recognize that some documentation is very old by looking
1846 at the modification time, so it would be nice if the
1847 modification time of the upstream source would be
1854 <sect id="debianrules"><heading><tt>debian/rules</tt> - the
1855 main building script </heading>
1858 This file must be an executable makefile, and contains the
1859 package-specific recipes for compiling the package and
1860 building binary package(s) out of the source.
1864 It must start with the line <tt>#!/usr/bin/make -f</tt>,
1865 so that it can be invoked by saying its name rather than
1866 invoking <prgn>make</prgn> explicitly.
1870 Since an interactive <tt>debian/rules</tt> script makes it
1871 impossible to auto-compile that package and also makes it
1872 hard for other people to reproduce the same binary
1873 package, all <strong>required targets</strong> MUST be
1874 non-interactive. At a minimum, required targets are the
1875 ones called by <prgn>dpkg-buildpackage</prgn>, namely,
1876 <em>clean</em>, <em>binary</em>, <em>binary-arch</em>,
1877 <em>binary-indep</em>, and <em>build</em>. It also follows
1878 that any target that these targets depend on must also be
1883 The targets which must be present are:
1885 <tag><tt>build</tt></tag>
1888 This should perform all non-interactive
1889 configuration and compilation of the package. If a
1890 package has an interactive pre-build configuration
1891 routine, the Debianised source package should be
1892 built after this has taken place, so that it can be
1893 built without rerunning the configuration.
1897 For some packages, notably ones where the same
1898 source tree is compiled in different ways to produce
1899 two binary packages, the <prgn>build</prgn> target
1900 does not make much sense. For these packages it is
1901 good enough to provide two (or more) targets
1902 (<tt>build-a</tt> and <tt>build-b</tt> or whatever)
1903 for each of the ways of building the package, and a
1904 <prgn>build</prgn> target that does nothing. The
1905 <prgn>binary</prgn> target will have to build the
1906 package in each of the possible ways and make the
1907 binary package out of each.
1911 The <prgn>build</prgn> target must not do anything
1912 that might require root privilege.
1916 The <prgn>build</prgn> target may need to run
1917 <prgn>clean</prgn> first - see below.
1921 When a package has a configuration routine that
1922 takes a long time, or when the makefiles are poorly
1923 designed, or when <prgn>build</prgn> needs to run
1924 <prgn>clean</prgn> first, it is a good idea to
1925 <tt>touch build</tt> when the build process is
1926 complete. This will ensure that if <tt>debian/rules
1927 build</tt> is run again it will not rebuild the
1932 <tag><tt>binary</tt>, <tt>binary-arch</tt>,
1933 <tt>binary-indep</tt>
1937 The <prgn>binary</prgn> target must be all that is
1938 necessary for the user to build the binary
1939 package. All these targets are required to be
1940 non-interactive. It is split into two parts:
1941 <prgn>binary-arch</prgn> builds the packages' output
1942 files which are specific to a particular
1943 architecture, and <prgn>binary-indep</prgn> builds
1944 those which are not.
1948 <prgn>binary</prgn> may be (and commonly is) a target
1949 with no commands which simply depends on
1950 <prgn>binary-arch</prgn> and
1951 <prgn>binary-indep</prgn>.
1955 Both <prgn>binary-*</prgn> targets should depend on
1956 the <prgn>build</prgn> target, above, so that the
1957 package is built if it has not been already. It
1958 should then create the relevant binary package(s),
1959 using <prgn>dpkg-gencontrol</prgn> to make their
1960 control files and <prgn>dpkg-deb</prgn> to build
1961 them and place them in the parent of the top level
1966 If one of the <prgn>binary-*</prgn> targets has
1967 nothing to do (this will be always be the case if
1968 the source generates only a single binary package,
1969 whether architecture-dependent or not) it
1970 <em>must</em> still exist, and must always
1975 The <prgn>binary</prgn> targets must be invoked as
1980 <tag><tt>clean</tt></tag>
1984 This must undo any effects that the
1985 <prgn>build</prgn> and <prgn>binary</prgn> targets
1986 may have had, except that it should leave alone any
1987 output files created in the parent directory by a
1988 run of <prgn>binary</prgn>. This target must be
1993 If a <prgn>build</prgn> file is touched at the end
1994 of the <prgn>build</prgn> target, as suggested
1995 above, it should be removed as the first thing that
1996 <prgn>clean</prgn> does, so that running
1997 <prgn>build</prgn> again after an interrupted
1998 <prgn>clean</prgn> doesn't think that everything is
2003 The <prgn>clean</prgn> target may need to be
2004 invoked as root if <prgn>binary</prgn> has been
2005 invoked since the last <prgn>clean</prgn>, or if
2006 <prgn>build</prgn> has been invoked as root (since
2007 <prgn>build</prgn> may create directories, for
2012 <tag><tt>get-orig-source</tt> (optional)</tag>
2016 This target fetches the most recent version of the
2017 original source package from a canonical archive site
2018 (via FTP or WWW, for example), does any necessary
2019 rearrangement to turn it into the original source
2020 tar file format described below, and leaves it in the
2025 This target may be invoked in any directory, and
2026 should take care to clean up any temporary files it
2031 This target is optional, but providing it if
2032 possible is a good idea.
2038 The <prgn>build</prgn>, <prgn>binary</prgn> and
2039 <prgn>clean</prgn> targets must be invoked with a current
2040 directory of the package's top-level directory.
2045 Additional targets may exist in <tt>debian/rules</tt>,
2046 either as published or undocumented interfaces or for the
2047 package's internal use.
2051 The architecture we build on and build for is determined by
2052 make variables via dpkg-architecture. You can get the Debian
2053 architecture and the GNU style architecture specification
2054 string for the build machine as well as the host
2055 machine. Here is a list of supported make variables:
2056 <list compact="compact">
2058 <p><tt>DEB_*_ARCH</tt> (the Debian architecture)</p>
2061 <p><tt>DEB_*_GNU_TYPE</tt> (the GNU style architecture
2062 specification string)</p>
2065 <p><tt>DEB_*_GNU_CPU</tt> (the CPU part of DEB_*_GNU_TYPE)</p>
2068 <p><tt>DEB_*_GNU_SYSTEM</tt> (the System part of
2074 where <tt>*</tt> is either <tt>BUILD</tt> for specification of
2075 the build machine or <tt>HOST</tt> for specification of the machine
2080 Backward compatibility can be provided in the rules file
2081 by setting the needed variables to suitable default
2082 values, please refer to the documentation of
2083 dpkg-architecture for details.
2087 It is important to understand that the <tt>DEB_*_ARCH</tt>
2088 string only determines which Debian architecture we are
2089 building on or for. It should not be used to get the CPU
2090 or system information; the GNU style variables should be
2095 <sect id="dpkgchangelog"><heading><tt>debian/changelog</tt>
2099 This file records the changes to the Debian-specific parts of the
2103 Though there is nothing stopping an author who is also
2104 the Debian maintainer from using it for all their
2105 changes, it will have to be renamed if the Debian and
2106 upstream maintainers become different
2113 It has a special format which allows the package building
2114 tools to discover which version of the package is being
2115 built and find out other release-specific information.
2119 That format is a series of entries like this:
2121 <var>package</var> (<var>version</var>) <var>distribution(s)</var>; urgency=<var>urgency</var>
2123 * <var>change details</var>
2124 <var>more change details</var>
2125 * <var>even more change details</var>
2127 -- <var>maintainer name and email address</var> <var>date</var>
2132 <var>package</var> and <var>version</var> are the source
2133 package name and version number.
2137 <var>distribution(s)</var> lists the distributions where
2138 this version should be installed when it is uploaded - it
2139 is copied to the <tt>Distribution</tt> field in the
2140 <tt>.changes</tt> file. See <ref id="f-Distribution">.
2144 <var>urgency</var> is the value for the <tt>Urgency</tt>
2145 field in the <tt>.changes</tt> file for the upload. It is
2146 not possible to specify an urgency containing commas; commas
2147 are used to separate
2148 <tt><var>keyword</var>=<var>value</var></tt> settings in the
2149 <prgn>dpkg</prgn> changelog format (though there is
2150 currently only one useful <var>keyword</var>,
2155 The change details may in fact be any series of lines
2156 starting with at least two spaces, but conventionally each
2157 change starts with an asterisk and a separating space and
2158 continuation lines are indented so as to bring them in
2159 line with the start of the text above. Blank lines may be
2160 used here to separate groups of changes, if desired.
2164 The maintainer name and email address need <em>not</em>
2165 necessarily be those of the usual package maintainer.
2166 They should be the details of the person doing
2167 <em>this</em> version. The information here will be
2168 copied to the <tt>.changes</tt> file, and then later used
2169 to send an acknowledgement when the upload has been
2174 The <var>date</var> should be in RFC822 format
2177 This is generated by the <prgn>822-date</prgn>
2180 </footnote>; it should include the time zone specified
2181 numerically, with the time zone name or abbreviation
2182 optionally present as a comment.
2186 The first `title' line with the package name should start
2187 at the left hand margin; the `trailer' line with the
2188 maintainer and date details should be preceded by exactly
2189 one space. The maintainer details and the date must be
2190 separated by exactly two spaces.
2193 <sect1><heading>Defining alternative changelog formats</heading>
2196 It is possible to use a different format to the standard
2197 one, by providing a parser for the format you wish to
2201 A changelog parser must not interact with the user at
2207 <sect id="srcsubstvars"><heading><tt>debian/substvars</tt>
2208 and variable substitutions </heading>
2211 When <prgn>dpkg-gencontrol</prgn>,
2212 <prgn>dpkg-genchanges</prgn> and <prgn>dpkg-source</prgn>
2213 generate control files they do variable substitutions on
2214 their output just before writing it. Variable
2215 substitutions have the form
2216 <tt>${<var>variable-name</var>}</tt>. The optional file
2217 <tt>debian/substvars</tt> contains variable substitutions
2218 to be used; variables can also be set directly from
2219 <tt>debian/rules</tt> using the <tt>-V</tt> option to the
2220 source packaging commands, and certain predefined
2221 variables are available.
2225 The is usually generated and modified dynamically by
2226 <tt>debian/rules</tt> targets; in this case it must be
2227 removed by the <prgn>clean</prgn> target.
2231 See <manref name="dpkg-source" section="1"> for full
2232 details about source variable substitutions, including the
2233 format of <tt>debian/substvars</tt>.</p>
2236 <sect id="debianfiles"><heading><tt>debian/files</tt>
2240 This file is not a permanent part of the source tree; it
2241 is used while building packages to record which files are
2242 being generated. <prgn>dpkg-genchanges</prgn> uses it
2243 when it generates a <tt>.changes</tt> file.
2247 It should not exist in a shipped source package, and so it
2248 (and any backup files or temporary files such as
2252 <tt>files.new</tt> is used as a temporary file by
2253 <prgn>dpkg-gencontrol</prgn> and
2254 <prgn>dpkg-distaddfile</prgn> - they write a new
2255 version of <tt>files</tt> here before renaming it,
2256 to avoid leaving a corrupted copy if an error
2259 </footnote>) should be removed by the
2260 <prgn>clean</prgn> target. It may also be wise to
2261 ensure a fresh start by emptying or removing it at the
2262 start of the <prgn>binary</prgn> target.
2266 <prgn>dpkg-gencontrol</prgn> adds an entry to this file
2267 for the <tt>.deb</tt> file that will be created by
2268 <prgn>dpkg-deb</prgn> from the control file that it
2269 generates, so for most packages all that needs to be done
2270 with this file is to delete it in <prgn>clean</prgn>.
2274 If a package upload includes files besides the source
2275 package and any binary packages whose control files were
2276 made with <prgn>dpkg-gencontrol</prgn> then they should be
2277 placed in the parent of the package's top-level directory
2278 and <prgn>dpkg-distaddfile</prgn> should be called to add
2279 the file to the list in <tt>debian/files</tt>.</p>
2282 <sect id="restrictions"><heading>Restrictions on objects in source packages
2286 The source package may not contain any hard links
2289 This is not currently detected when building source
2290 packages, but only when extracting
2296 Hard links may be permitted at some point in the
2297 future, but would require a fair amount of
2300 </footnote>, device special files, sockets or setuid or
2304 Setgid directories are allowed.
2309 <sect id="descriptions"><heading>Descriptions of packages - the
2310 <tt>Description</tt> field </heading>
2313 The description is intended to describe the program to a user
2314 who has never met it before so that they know whether they
2315 want to install it. It should also give information about the
2316 significant dependencies and conflicts between this package
2317 and others, so that the user knows why these dependencies and
2318 conflicts have been declared.
2321 <sect1><heading>Notes about writing descriptions
2325 The single line synopsis should be kept brief - certainly
2326 under 80 characters.
2330 Do not include the package name in the synopsis line. The
2331 display software knows how to display this already, and you
2332 do not need to state it. Remember that in many situations
2333 the user may only see the synopsis line - make it as
2334 informative as you can.
2338 Do not try to continue the single line synopsis into the
2339 extended description. This will not work correctly when
2340 the full description is displayed, and makes no sense
2341 where only the summary (the single line synopsis) is
2346 The extended description should describe what the package
2347 does and how it relates to the rest of the system (in terms
2348 of, for example, which subsystem it is which part of).
2352 The description field needs to make sense to anyone, even
2353 people who have no idea about any of the things the
2357 The blurb that comes with a program in its
2358 announcements and/or <prgn>README</prgn> files is
2359 rarely suitable for use in a description. It is
2360 usually aimed at people who are already in the
2361 community where the package is used.
2367 Put important information first, both in the synopsis and
2368 extended description. Sometimes only the first part of the
2369 synopsis or of the description will be displayed. You can
2370 assume that there will usually be a way to see the whole
2371 extended description.
2375 You may include information about dependencies and so forth
2376 in the extended description, if you wish.
2380 Do not use tab characters. Their effect is not predictable.
2388 <chapt id="maintainerscripts"><heading>Package maintainer scripts
2389 and installation procedure
2392 <sect><heading>Introduction to package maintainer scripts
2396 It is possible to supply scripts as part of a package which
2397 the package management system will run for you when your
2398 package is installed, upgraded or removed.
2402 These scripts should be the files <tt>preinst</tt>,
2403 <tt>postinst</tt>, <tt>prerm</tt> and <tt>postrm</tt> in the
2404 control area of the package. They must be proper executable
2405 files; if they are scripts (which is recommended) they must
2406 start with the usual <tt>#!</tt> convention. They should be
2407 readable and executable by anyone, and not world-writable.
2411 The package management system looks at the exit status from
2412 these scripts. It is important that they exit with a
2413 non-zero status if there is an error, so that the package
2414 management system can stop its processing. For shell
2415 scripts this means that you <em>almost always</em> need to
2416 use <tt>set -e</tt> (this is usually true when writing shell
2417 scripts, in fact). It is also important, of course, that
2418 they don't exit with a non-zero status if everything went
2423 It is necessary for the error recovery procedures that the
2424 scripts be idempotent: i.e., invoking the same script several
2425 times in the same situation should do no harm. If the first
2426 call failed, or aborted half way through for some reason,
2427 the second call should merely do the things that were left
2428 undone the first time, if any, and exit with a success
2433 When a package is upgraded a combination of the scripts from
2434 the old and new packages is called in amongst the other
2435 steps of the upgrade procedure. If your scripts are going
2436 to be at all complicated you need to be aware of this, and
2437 may need to check the arguments to your scripts.
2441 Broadly speaking the <prgn>preinst</prgn> is called before
2442 (a particular version of) a package is installed, and the
2443 <prgn>postinst</prgn> afterwards; the <prgn>prerm</prgn>
2444 before (a version of) a package is removed and the
2445 <prgn>postrm</prgn> afterwards.
2448 <p> Programs called from maintainer scripts should not
2449 normally have a path prepended to them. Before installation
2450 is started the package management system checks to see if
2451 the programs <prgn>ldconfig</prgn>,
2452 <prgn>start-stop-daemon</prgn>, <prgn>install-info</prgn>,
2453 and <prgn>update-rc.d</prgn> can be found via the
2454 <tt>PATH</tt> environment variable. Those programs, and any
2455 other program that one would expect to on the <tt>PATH</tt>,
2456 should thus be invoked without an absolute
2457 pathname. Maintainer scripts should also not reset the
2458 <tt>PATH</tt>, though they might choose to modify it by pre-
2459 or appending package-specific directories. These
2460 considerations really apply to all shell scripts.</p>
2463 <heading>Maintainer scripts Idempotency</heading>
2466 It is very important to make maintainer scripts
2470 That means that if it runs successfully or fails
2471 and then you call it again it doesn't bomb out,
2472 but just ensures that everything is the way it
2475 </footnote> This is so that if an error occurs, the
2476 user interrupts <prgn>dpkg</prgn> or some other
2477 unforeseen circumstance happens you don't leave the
2478 user with a badly-broken package.
2482 <heading>Controlling terminal for maintainer scripts</heading>
2485 The maintainer scripts are guaranteed to run with a
2486 controlling terminal and can interact with the user.
2487 If they need to prompt for passwords, do full-screen
2488 interaction or something similar you should do these
2489 things to and from <tt>/dev/tty</tt>, since
2490 <prgn>dpkg</prgn> will at some point redirect scripts'
2491 standard input and output so that it can log the
2492 installation process. Likewise, because these scripts
2493 may be executed with standard output redirected into a
2494 pipe for logging purposes, Perl scripts should set
2495 unbuffered output by setting <tt>$|=1</tt> so that the
2496 output is printed immediately rather than being
2501 Each script should return a zero exit status for
2502 success, or a nonzero one for failure.
2506 <sect id="mscriptsinstact"><heading>Summary of ways maintainer
2511 <list compact="compact">
2513 <p><var>new-preinst</var> <tt>install</tt></p>
2516 <p><var>new-preinst</var> <tt>install</tt>
2517 <var>old-version</var></p>
2520 <p><var>new-preinst</var> <tt>upgrade</tt>
2521 <var>old-version</var></p>
2524 <p><var>old-preinst</var> <tt>abort-upgrade</tt>
2525 <var>new-version</var>
2531 <list compact="compact">
2533 <p><var>postinst</var> <tt>configure</tt>
2534 <var>most-recently-configured-version</var></p>
2537 <p><var>old-postinst</var> <tt>abort-upgrade</tt>
2538 <var>new version</var></p>
2541 <p><var>conflictor's-postinst</var> <tt>abort-remove</tt>
2542 <tt>in-favour</tt> <var>package</var>
2543 <var>new-version</var></p>
2547 <var>deconfigured's-postinst</var>
2548 <tt>abort-deconfigure</tt> <tt>in-favour</tt>
2549 <var>failed-install-package</var> <var>version</var>
2550 <tt>removing</tt> <var>conflicting-package</var>
2557 <list compact="compact">
2559 <p><var>prerm</var> <tt>remove</tt></p>
2562 <p><var>old-prerm</var> <tt>upgrade</tt>
2563 <var>new-version</var></p>
2566 <p><var>new-prerm</var> <tt>failed-upgrade</tt>
2567 <var>old-version</var></p>
2570 <p><var>conflictor's-prerm</var> <tt>remove</tt>
2571 <tt>in-favour</tt> <var>package</var>
2572 <var>new-version</var></p>
2576 <var>deconfigured's-prerm</var> <tt>deconfigure</tt>
2577 <tt>in-favour</tt> <var>package-being-installed</var>
2578 <var>version</var> <tt>removing</tt>
2579 <var>conflicting-package</var>
2586 <list compact="compact">
2588 <p><var>postrm</var> <tt>remove</tt></p>
2591 <p><var>postrm</var> <tt>purge</tt></p>
2595 <var>old-postrm</var> <tt>upgrade</tt>
2596 <var>new-version</var></p>
2599 <p><var>new-postrm</var> <tt>failed-upgrade</tt>
2600 <var>old-version</var></p>
2603 <p><var>new-postrm</var> <tt>abort-install</tt></p>
2606 <p><var>new-postrm</var> <tt>abort-install</tt>
2607 <var>old-version</var></p>
2610 <p><var>new-postrm</var> <tt>abort-upgrade</tt>
2611 <var>old-version</var></p>
2615 <var>disappearer's-postrm</var> <tt>disappear</tt>
2616 <var>overwriter</var>
2617 <var>overwriter-version</var></p></item>
2622 <sect id="unpackphase"><heading>Details of unpack phase of
2623 installation or upgrade
2627 The procedure on installation/upgrade/overwrite/disappear
2628 (i.e., when running <tt>dpkg --unpack</tt>, or the unpack
2629 stage of <tt>dpkg --install</tt>) is as follows. In each
2630 case if an error occurs the actions are, in general, run
2631 backwards - this means that the maintainer scripts are run
2632 with different arguments in reverse order. These are the
2633 `error unwind' calls listed below.
2640 <p>If a version of the package is already
2643 <var>old-prerm</var> upgrade <var>new-version</var>
2648 If the script runs but exits with a non-zero
2649 exit status, <prgn>dpkg</prgn> will attempt:
2651 <var>new-prerm</var> failed-upgrade <var>old-version</var>
2653 Error unwind, for both the above cases:
2655 <var>old-postinst</var> abort-upgrade <var>new-version</var>
2663 <p>If a `conflicting' package is being removed at the same time:
2667 If any packages depended on that conflicting
2668 package and <tt>--auto-deconfigure</tt> is
2669 specified, call, for each such package:
2671 <var>deconfigured's-prerm</var> deconfigure \
2672 in-favour <var>package-being-installed</var> <var>version</var> \
2673 removing <var>conflicting-package</var> <var>version</var>
2677 <var>deconfigured's-postinst</var> abort-deconfigure \
2678 in-favour <var>package-being-installed-but-failed</var> <var>version</var> \
2679 removing <var>conflicting-package</var> <var>version</var>
2681 The deconfigured packages are marked as
2682 requiring configuration, so that if
2683 <tt>--install</tt> is used they will be
2684 configured again if possible.</p>
2687 <p>To prepare for removal of the conflicting package, call:
2689 <var>conflictor's-prerm</var> remove in-favour <var>package</var> <var>new-version</var>
2693 <var>conflictor's-postinst</var> abort-remove \
2694 in-favour <var>package</var> <var>new-version</var>
2705 <p>If the package is being upgraded, call:
2707 <var>new-preinst</var> upgrade <var>old-version</var>
2712 Otherwise, if the package had some configuration
2713 files from a previous version installed (i.e., it
2714 is in the `configuration files only' state):
2716 <var>new-preinst</var> install <var>old-version</var>
2720 <p>Otherwise (i.e., the package was completely purged):
2722 <var>new-preinst</var> install
2724 Error unwind versions, respectively:
2726 <var>new-postrm</var> abort-upgrade <var>old-version</var>
2727 <var>new-postrm</var> abort-install <var>old-version</var>
2728 <var>new-postrm</var> abort-install
2738 The new package's files are unpacked, overwriting any
2739 that may be on the system already, for example any
2740 from the old version of the same package or from
2741 another package (backups of the old files are left
2742 around, and if anything goes wrong the package
2743 management system will attempt to put them back as
2744 part of the error unwind).
2748 It is an error for a package to contains files which
2749 are on the system in another package, unless
2750 <tt>Replaces</tt> is used (see <ref id="replaces">).
2751 Currently the <tt>--force-overwrite</tt> flag is
2752 enabled, downgrading it to a warning, but this may not
2757 It is a more serious error for a package to contain a
2758 plain file or other kind of non-directory where another
2759 package has a directory (again, unless
2760 <tt>Replaces</tt> is used). This error can be
2761 overridden if desired using
2762 <tt>--force-overwrite-dir</tt>, but this is not
2767 Packages which overwrite each other's files produce
2768 behavior which though deterministic is hard for the
2769 system administrator to understand. It can easily
2770 lead to `missing' programs if, for example, a package
2771 is installed which overwrites a file from another
2772 package, and is then removed again.
2775 Part of the problem is due to what is arguably a
2776 bug in <prgn>dpkg</prgn>.
2782 A directory will never be replaced by a symbolic links
2783 to a directory or vice versa; instead, the existing
2784 state (symlink or not) will be left alone and
2785 <prgn>dpkg</prgn> will follow the symlink if there is
2793 <p>If the package is being upgraded, call
2795 <var>old-postrm</var> upgrade <var>new-version</var>
2799 <p>If this fails, <prgn>dpkg</prgn> will attempt:
2801 <var>new-postrm</var> failed-upgrade <var>old-version</var>
2803 Error unwind, for both cases:
2805 <var>old-preinst</var> abort-upgrade <var>new-version</var>
2811 This is the point of no return - if
2812 <prgn>dpkg</prgn> gets this far, it won't back off
2813 past this point if an error occurs. This will
2814 leave the package in a fairly bad state, which
2815 will require a successful re-installation to clear
2816 up, but it's when <prgn>dpkg</prgn> starts doing
2817 things that are irreversible.
2822 Any files which were in the old version of the package
2823 but not in the new are removed.</p>
2826 <p>The new file list replaces the old.</p>
2829 <p>The new maintainer scripts replace the old.</p>
2833 <p>Any packages all of whose files have been overwritten during the
2834 installation, and which aren't required for
2835 dependencies, are considered to have been removed.
2836 For each such package,
2839 <p><prgn>dpkg</prgn> calls:
2841 <var>disappearer's-postrm</var> disappear \
2842 <var>overwriter</var> <var>overwriter-version</var>
2847 <p>The package's maintainer scripts are removed.
2852 It is noted in the status database as being in a
2853 sane state, namely not installed (any conffiles
2854 it may have are ignored, rather than being
2855 removed by <prgn>dpkg</prgn>). Note that
2856 disappearing packages do not have their prerm
2857 called, because <prgn>dpkg</prgn> doesn't know
2858 in advance that the package is going to
2867 Any files in the package we're unpacking that are also
2868 listed in the file lists of other packages are removed
2869 from those lists. (This will lobotomize the file list
2870 of the `conflicting' package if there is one.)
2875 The backup files made during installation, above, are
2882 The new package's status is now sane, and recorded as
2883 `unpacked'. Here is another point of no return - if
2884 the conflicting package's removal fails we do not
2885 unwind the rest of the installation; the conflicting
2886 package is left in a half-removed limbo.
2891 If there was a conflicting package we go and do the
2892 removal actions (described below), starting with the
2893 removal of the conflicting package's files (any that
2894 are also in the package being installed have already
2895 been removed from the conflicting package's file list,
2896 and so do not get removed now).
2903 <sect><heading>Details of configuration</heading>
2906 When we configure a package (this happens with <tt>dpkg
2907 --install</tt>, or with <tt>--configure</tt>), we first
2908 update the conffiles and then call:
2910 <var>postinst</var> configure <var>most-recently-configured-version</var>
2915 No attempt is made to unwind after errors during
2920 If there is no most recently configured version
2921 <prgn>dpkg</prgn> will pass a null argument; older versions
2922 of dpkg may pass <tt><unknown></tt> (including the
2923 angle brackets) in this case. Even older ones do not pass a
2924 second argument at all, under any circumstances.
2928 <sect><heading>Details of removal and/or configuration purging
2936 <var>prerm</var> remove
2942 The package's files are removed (except conffiles).
2947 <var>postrm</var> remove
2951 <p>All the maintainer scripts except the postrm are removed.
2955 If we aren't purging the package we stop here. Note
2956 that packages which have no postrm and no conffiles
2957 are automatically purged when removed, as there is no
2958 difference except for the <prgn>dpkg</prgn>
2963 The conffiles and any backup files (<tt>~</tt>-files,
2964 <tt>#*#</tt> files, <tt>%</tt>-files,
2965 <tt>.dpkg-{old,new,tmp}</tt>, etc.) are removed.</p>
2969 <var>postrm</var> purge
2973 <p>The package's file list is removed.</p>
2976 No attempt is made to unwind after errors during
2982 <chapt id="relationships"><heading>Declaring relationships between
2986 Packages can declare in their control file that they have
2987 certain relationships to other packages - for example, that
2988 they may not be installed at the same time as certain other
2989 packages, and/or that they depend on the presence of others,
2990 or that they should overwrite files in certain other packages
2995 This is done using the <tt>Depends</tt>, <tt>Recommends</tt>,
2996 <tt>Suggests</tt>, <tt>Enhances</tt>, <tt>Conflicts</tt>,
2997 <tt>Provides</tt> and <tt>Replaces</tt> control file fields.
3001 Source packages may declare relationships to binary packages,
3002 saying that they require certain binary packages to be
3003 installed or absent at the time of building the package.
3007 This is done using the <tt>Build-Depends</tt>,
3008 <tt>Build-Depends-Indep</tt>, <tt>Build-Conflicts</tt>, and
3009 <tt>Build-Conflicts-Indep</tt> control file fields.
3012 <sect id="depsyntax"><heading>Syntax of relationship fields
3016 These fields all have a uniform syntax. They are a list of
3017 package names separated by commas.
3021 In the <tt>Depends</tt>, <tt>Recommends</tt>,
3022 <tt>Suggests</tt>, <tt>Pre-Depends</tt>,
3023 <tt>Build-Depends</tt> and <tt>Build-Depends-Indep</tt>
3024 control file fields of the package, which declare
3025 dependencies on other packages, the package names listed may
3026 also include lists of alternative package names, separated
3027 by vertical bar symbols <tt>|</tt> (pipe symbols). In such
3028 a case, the presence of any one of the alternative packages
3029 is installed, that part of the dependency is considered to
3034 All the fields except <tt>Provides</tt> may restrict their
3035 applicability to particular versions of each named package.
3036 This is done in parentheses after each individual package
3037 name; the parentheses should contain a relation from the
3038 list below followed by a version number, in the format
3039 described in <ref id="versions">.
3043 The relations allowed are <tt><<</tt>, <tt><=</tt>,
3044 <tt>=</tt>, <tt>>=</tt> and <tt>>></tt> for
3045 strictly earlier, earlier or equal, exactly equal, later or
3046 equal and strictly later, respectively. The forms
3047 <tt><</tt> and <tt>></tt> were used to mean
3048 earlier/later or equal, rather than strictly earlier/later,
3049 so they should not appear in new packages (though
3050 <prgn>dpkg</prgn> still supports them).
3054 Whitespace may appear at any point in the version
3055 specification, and must appear where it's necessary to
3056 disambiguate; it is not otherwise significant. For
3057 consistency and in case of future changes to
3058 <prgn>dpkg</prgn> it is recommended that a single space be
3059 used after a version relationship and before a version
3060 number; it is usual also to put a single space after each
3061 comma, on either side of each vertical bar, and before each
3070 Depends: libc5 (>= 5.2.18-4), mime-support, csh | tcsh
3075 All fields that specify build-time relationships
3076 (<tt>Build-Depends</tt>, <tt>Build-Depends-Indep</tt>,
3077 <tt>Build-Conflicts</tt> and <tt>Build-Conflicts-Indep</tt>)
3078 may be restricted to a certain set of architectures. This
3079 is done in brackets after each individual package name and
3080 the optional version specification. The brackets enclose a
3081 list of Debian architecture names separated by whitespace.
3082 An exclamation mark may be prepended to each name. If the
3083 current Debian host architecture is not in this list and
3084 there are no exclamation marks in the list, or it is in the
3085 list with a prepended exclamation mark, the package name and
3086 the associated version specification are ignored completely
3087 for the purposes of defining the relationships.
3094 Build-Depends-Indep: texinfo
3095 Build-Depends: kernel-headers-2.2.10 [!hurd-i386],
3096 hurd-dev [hurd-i386], gnumach-dev [hurd-i386]
3102 <heading>Binary Dependencies - <tt>Depends</tt>,
3103 <tt>Recommends</tt>, <tt>Suggests</tt>, <tt>Enhances</tt>,
3104 <tt>Pre-Depends</tt>
3108 These five fields are used to declare a dependency
3109 relationship by one package on another. They appear in the
3110 depending package's control file.
3114 All but <tt>Pre-Depends</tt> and <tt>Conflicts</tt>
3115 (discussed below) take effect <em>only</em> when a package
3116 is to be configured. They do not prevent a package being on
3117 the system in an unconfigured state while its dependencies
3118 are unsatisfied, and it is possible to replace a package
3119 whose dependencies are satisfied and which is properly
3120 installed with a different version whose dependencies are
3121 not and cannot be satisfied; when this is done the depending
3122 package will be left unconfigured (since attempts to
3123 configure it will give errors) and will not function
3128 For this reason packages in an installation run are usually
3129 all unpacked first and all configured later; this gives
3130 later versions of packages with dependencies on later
3131 versions of other packages the opportunity to have their
3132 dependencies satisfied.
3136 Thus <tt>Depends</tt> allows package maintainers to impose
3137 an order in which packages should be configured.
3139 <tag><tt>Depends</tt></tag>
3142 <p>This declares an absolute dependency.
3146 The <tt>Depends</tt> field should be used if the
3147 depended-on package is required for the depending
3148 package to provide a significant amount of
3152 <tag><tt>Recommends</tt></tag>
3154 <p>This declares a strong, but not absolute, dependency.
3158 The <tt>Recommends</tt> field should list packages
3159 that would be found together with this one in all but
3160 unusual installations.</p>
3163 <tag><tt>Suggests</tt></tag>
3167 This is used to declare that one package may be more
3168 useful with one or more others. Using this field
3169 tells the packaging system and the user that the
3170 listed packages are related to this one and can
3171 perhaps enhance its usefulness, but that installing
3172 this one without them is perfectly reasonable.
3176 <tag><tt>Enhances</tt></tag>
3179 This field is similar to Suggests but works in the
3180 opposite direction. It is used to declare that a
3181 package can enhance the functionality of another
3186 <tag><tt>Pre-Depends</tt></tag>
3190 This field is like <tt>Depends</tt>, except that it
3191 also forces <prgn>dpkg</prgn> to complete installation
3192 of the packages named before even starting the
3193 installation of the package which declares the
3198 <tt>Pre-Depends</tt> should be used sparingly,
3199 preferably only by packages whose premature upgrade or
3200 installation would hamper the ability of the system to
3201 continue with any upgrade that might be in progress.
3205 When the package declaring it is being configured, a
3206 <tt>Pre-Dependency</tt> will be considered satisfied
3207 only if the depending package has been correctly
3208 configured, just as if an ordinary <tt>Depends</tt>
3213 However, when a package declaring a Pre-dependency is
3214 being unpacked the predependency can be satisfied even
3215 if the depended-on package(s) are only unpacked or
3216 half-configured, provided that they have been
3217 configured correctly at some point in the past (and
3218 not removed or partially removed since). In this case
3219 both the previously-configured and currently unpacked
3220 or half-configured versions must satisfy any version
3221 clause in the <tt>Pre-Depends</tt> field.
3227 When selecting which level of dependency to use you should
3228 consider how important the depended-on package is to the
3229 functionality of the one declaring the dependency. Some
3230 packages are composed of components of varying degrees of
3231 importance. Such a package should list using
3232 <tt>Depends</tt> the package(s) which are required by the
3233 more important components. The other components'
3234 requirements may be mentioned as Suggestions or
3235 Recommendations, as appropriate to the components' relative
3240 <sect id="conflicts"><heading>Alternative binary packages -
3241 <tt>Conflicts</tt> and <tt>Replaces</tt>
3245 When one binary package declares a conflict with another
3246 <prgn>dpkg</prgn> will refuse to allow them to be installed
3247 on the system at the same time.
3251 If one package is to be installed, the other must be removed
3252 first - if the package being installed is marked as
3253 replacing (<ref id="replaces">) the one on the system, or
3254 the one on the system is marked as deselected, or both
3255 packages are marked <tt>Essential</tt>, then
3256 <prgn>dpkg</prgn> will automatically remove the package
3257 which is causing the conflict, otherwise it will halt the
3258 installation of the new package with an error. This
3259 mechanism specifically doesn't work when the installed
3260 package is <tt>Essential</tt>, but the new package is not.
3265 A package will not cause a conflict merely because its
3266 configuration files are still installed; it must be at least
3271 A special exception is made for packages which declare a
3272 conflict with their own package name, or with a virtual
3273 package which they provide (see below): this does not
3274 prevent their installation, and allows a package to conflict
3275 with others providing a replacement for it. You use this
3276 feature when you want the package in question to be the only
3277 package providing something.
3281 A <tt>Conflicts</tt> entry should almost never have an
3282 `earlier than' version clause. This would prevent
3283 <prgn>dpkg</prgn> from upgrading or installing the package
3284 which declared such a conflict until the upgrade or removal
3285 of the conflicted-with package had been completed.
3289 <sect id="virtual"><heading>Virtual packages - <tt>Provides</tt>
3293 As well as the names of actual (`concrete') packages, the
3294 package relationship fields <tt>Depends</tt>,
3295 <tt>Build-Depends</tt>, <tt>Build-Depends-Indep</tt>,
3296 <tt>Recommends</tt>, <tt>Suggests</tt>, <tt>Conflicts</tt>,
3297 <tt>Build-Conflicts</tt> and <tt>Build-Conflicts-Indep</tt> may
3298 mention virtual packages.
3302 A virtual package is one which appears in the
3303 <tt>Provides</tt> control file field of another package.
3304 The effect is as if the package(s) which provide a
3305 particular virtual package name had been listed by name
3306 everywhere the virtual package name appears.
3310 If there are both a real and a virtual package of the same
3311 name then the dependency may be satisfied (or the conflict
3312 caused) by either the real package or any of the virtual
3313 packages which provide it. This is so that, for example,
3319 and someone else releases an xemacs package they can say
3323 </example> and all will work in the interim (until a purely
3324 virtual package name is decided on and the <tt>emacs</tt>
3325 and <tt>vm</tt> packages are changed to use it).
3329 If a dependency or a conflict has a version number attached
3330 then only real packages will be considered to see whether
3331 the relationship is satisfied (or the prohibition violated,
3332 for a conflict) - it is assumed that a real package which
3333 provides the virtual package is not of the `right' version.
3334 So, a <tt>Provides</tt> field may not contain version
3335 numbers, and the version number of the concrete package
3336 which provides a particular virtual package will not be
3337 looked at when considering a dependency on or conflict with
3338 the virtual package name.
3342 It is likely that the ability will be added in a future
3343 release of <prgn>dpkg</prgn> to specify a version number for
3344 each virtual package it provides. This feature is not yet
3345 present, however, and is expected to be used only
3350 If you want to specify which of a set of real packages should be the
3351 default to satisfy a particular dependency on a virtual package, you
3352 should list the real package as an alternative before the virtual.
3357 <sect id="replaces"><heading><tt>Replaces</tt> - overwriting
3358 files and replacing packages
3362 The <tt>Replaces</tt> control file field has two purposes,
3363 which come into play in different situations.
3367 Virtual packages (<ref id="virtual">) are not considered
3368 when looking at a <tt>Replaces</tt> field - the packages
3369 declared as being replaced must be mentioned by their real
3373 <sect1><heading>Overwriting files in other packages
3377 Firstly, as mentioned before, it is usually an error for a
3378 package to contain files which are on the system in
3379 another package, though currently the
3380 <tt>--force-overwrite</tt> flag is enabled by default,
3381 downgrading the error to a warning,
3385 If the overwriting package declares that it replaces the
3386 one containing the file being overwritten then
3387 <prgn>dpkg</prgn> will proceed, and replace the file from
3388 the old package with that from the new. The file will no
3389 longer be listed as `owned' by the old package.
3393 If a package is completely replaced in this way, so that
3394 <prgn>dpkg</prgn> does not know of any files it still
3395 contains, it is considered to have disappeared. It will
3396 be marked as not wanted on the system (selected for
3397 removal) and not installed. Any conffiles details noted
3398 in the package will be ignored, as they will have been
3399 taken over by the replacing package(s). The package's
3400 <prgn>postrm</prgn> script will be run to allow the
3401 package to do any final cleanup required. See <ref
3402 id="mscriptsinstact">.
3406 In the future <prgn>dpkg</prgn> will discard files which
3407 would overwrite those from an already installed package
3408 which declares that it replaces the package being
3409 installed. This is so that you can install an older
3410 version of a package without problems.
3414 This usage of <tt>Replaces</tt> only takes effect when
3415 both packages are at least partially on the system at
3416 once, so that it can only happen if they do not conflict
3417 or if the conflict has been overridden.</p>
3420 <sect1><heading>Replacing whole packages, forcing their
3425 Secondly, <tt>Replaces</tt> allows the packaging system to
3426 resolve which package should be removed when there is a
3427 conflict - see <ref id="conflicts">. This usage only
3428 takes effect when the two packages <em>do</em> conflict,
3429 so that the two effects do not interfere with each other.
3434 <sect><heading>Relationships between source and binary packages -
3435 <tt>Build-Depends</tt>, <tt>Build-Depends-Indep</tt>,
3436 <tt>Build-Conflicts</tt>, <tt>Build-Conflicts-Indep</tt>
3440 A source package may declare a dependency or a conflict on a
3441 binary package. This is done with the control file fields
3442 <tt>Build-Depends</tt>, <tt>Build-Depends-Indep</tt>,
3443 <tt>Build-Conflicts</tt>, and
3444 <tt>Build-Conflicts-Indep</tt>. Their semantics are that
3445 the dependencies and conflicts they define must be satisfied
3446 (as defined earlier for binary packages), when one of the
3447 targets in <tt>debian/rules</tt> that the particular field
3448 applies to is invoked.
3451 <tag><tt>Build-Depends</tt>, <tt>Build-Conflicts</tt></tag>
3454 The <tt>Build-Depends</tt> and
3455 <tt>Build-Conflicts</tt> fields apply to the targets
3456 <tt>build</tt>, <tt>binary</tt>, <tt>binary-arch</tt>
3457 and <tt>binary-indep</tt>.
3460 <tag><tt>Build-Depends-Indep</tt>, <tt>Build-Conflicts-Indep</tt></tag>
3463 The <tt>Build-Depends-Indep</tt> and
3464 <tt>Build-Conflicts-Indep</tt> fields apply to the
3465 targets <tt>binary</tt> and <tt>binary-indep</tt>.
3476 <chapt id="conffiles"><heading>Configuration file handling
3480 <prgn>dpkg</prgn> can do a certain amount of automatic
3481 handling of package configuration files.
3485 Whether this mechanism is appropriate depends on a number of
3486 factors, but basically there are two approaches to any
3487 particular configuration file.
3491 The easy method is to ship a best-effort configuration in the
3492 package, and use <prgn>dpkg</prgn>'s conffile mechanism to
3493 handle updates. If the user is unlikely to want to edit the
3494 file, but you need them to be able to without losing their
3495 changes, and a new package with a changed version of the file
3496 is only released infrequently, this is a good approach.
3500 The hard method is to build the configuration file from
3501 scratch in the <prgn>postinst</prgn> script, and to take the
3502 responsibility for fixing any mistakes made in earlier
3503 versions of the package automatically. This will be
3504 appropriate if the file is likely to need to be different on
3509 <chapt id="sharedlibs"><heading>Shared libraries
3513 Packages containing shared libraries must be constructed with
3514 a little care to make sure that the shared library is always
3515 available. This is especially important for packages whose
3516 shared libraries are vitally important, such as the libc.
3520 Firstly, your package should install the shared libraries
3521 under their normal names. For example, the
3522 <prgn>libgdbm1</prgn> package should install
3523 <tt>libgdbm.so.1.7.3</tt> as
3524 <tt>/usr/lib/libgdbm.so.1.7.3</tt>. The files should not be
3525 renamed or re-linked by any prerm or postrm scripts;
3526 <prgn>dpkg</prgn> will take care of renaming things safely
3527 without affecting running programs, and attempts to interfere
3528 with this are likely to lead to problems.
3532 Secondly, your package should include the symlink that
3533 <prgn>ldconfig</prgn> would create for the shared libraries.
3534 For example, the <prgn>libgdbm1</prgn> package should include
3535 a symlink from <tt>/usr/lib/libgdbm.so.1</tt> to
3536 <tt>libgdbm.so.1.7.3</tt>. This is needed so that
3537 <prgn>ld.so</prgn> can find the library in between the time
3538 <prgn>dpkg</prgn> installs it and <prgn>ldconfig</prgn> is run
3539 in the <prgn>postinst</prgn> script. Furthermore, older
3540 versions of the package management system required the library
3541 must be placed before the symlink pointing to it in the
3542 <tt>.deb</tt> file. This is so that by the time
3543 <prgn>dpkg</prgn> comes to install the symlink (overwriting
3544 the previous symlink pointing at an older version of the
3545 library) the new shared library is already in place.
3546 Unfortunately, this was not not always possible, since it
3547 highly depends on the behavior of the file system. Some
3548 file systems (such as reiserfs) will reorder the files so it
3549 doesn't matter in what order you create them. Starting with
3550 release <tt>1.7.0</tt> <prgn>dpkg</prgn> will reorder the
3551 files itself when building a package.
3555 Thirdly, the development package should contain a symlink for
3556 the shared library without a version number. For example, the
3557 <tt>libgdbm1-dev</tt> package should include a symlink from
3558 <tt>/usr/lib/libgdm.so</tt> to <tt>libgdm.so.1.7.3</tt>. This
3559 symlink is needed by <prgn>ld</prgn> when compiling packages
3560 as it will only look for <tt>libgdm.so</tt> and
3561 <tt>libgdm.a</tt> when compiling dynamically or statically,
3566 Any package installing shared libraries in a directory that's listed
3567 in <tt>/etc/ld.so.conf</tt> or in one of the default library
3568 directories of <prgn>ld.so</prgn> (currently, these are <tt>/usr/lib</tt>
3569 and <tt>/lib</tt>) must call <prgn>ldconfig</prgn> in its <prgn>postinst</prgn>
3570 script if and only if the first argument is `configure'. However, it
3571 is important not to call <prgn>ldconfig</prgn> in the postrm or preinst
3572 scripts in the case where the package is being upgraded (see <ref
3573 id="unpackphase">), as <prgn>ldconfig</prgn> will see the temporary names
3574 that <prgn>dpkg</prgn> uses for the files while it is
3575 installing them and will make the shared library links point
3576 to them, just before <prgn>dpkg</prgn> continues the
3577 installation and removes the links!
3580 <sect id="shlibs"><heading>The <tt>shlibs</tt> File Format
3584 This file is for use by <prgn>dpkg-shlibdeps</prgn> and is
3585 required when your package provides shared libraries.
3589 Each line is of the form:
3591 <var>library-name</var> <var>version-or-soname</var> <var>dependencies ...</var>
3596 <var>library-name</var> is the name of the shared library,
3597 for example <tt>libc5</tt>.
3601 <var>version-or-soname</var> is the soname of the library -
3602 i.e., the thing that must exactly match for the library to be
3603 recognized by <prgn>ld.so</prgn>. Usually this is the major
3604 version number of the library.
3608 <var>dependencies</var> has the same syntax as a dependency
3609 field in a binary package control file. It should give
3610 details of which package(s) are required to satisfy a binary
3611 built against the version of the library contained in the
3612 package. See <ref id="depsyntax">.
3616 For example, if the package <tt>foo</tt> contains
3617 <tt>libfoo.so.1.2.3</tt>, where the soname of the library is
3618 <tt>libfoo.so.1</tt>, and the first version of the package
3619 which contained a minor number of at least <tt>2.3</tt> was
3620 <var>1.2.3-1</var>, then the package's <var>shlibs</var>
3623 libfoo 1 foo (>= 1.2.3-1)
3628 The version-specific dependency is to avoid warnings from
3629 <prgn>ld.so</prgn> about using older shared libraries with
3633 <sect><heading>Further Technical information on
3634 <tt>shlibs</tt></heading>
3636 <sect1><heading><em>What</em> are the <tt>shlibs</tt> files?
3640 The <tt>debian/shlibs</tt> file provides a way of checking
3641 for shared library dependencies on packaged binaries.
3642 They are intended to be used by package maintainers to
3643 make their lives easier.
3647 Other <tt>shlibs</tt> files that exist on a Debian system are
3649 <item> <p><tt>/etc/dpkg/shlibs.default</tt></p></item>
3650 <item> <p><tt>/etc/dpkg/shlibs.override</tt></p></item>
3651 <item> <p><tt>/var/lib/dpkg/info/*.shlibs</tt></p></item>
3652 <item> <p><tt>debian/shlibs.local</tt></p></item>
3654 These files are used by <prgn>dpkg-shlibdeps</prgn> when
3655 creating a binary package.</p>
3658 <sect1><heading><em>How</em> does <prgn>dpkg-shlibdeps</prgn>
3662 <prgn>dpkg-shlibdeps</prgn>
3663 determines the shared libraries directly
3666 It used to do this by calling <prgn>ldd</prgn>, but it
3667 now calls <prgn>objdump</prgn> to to this. This
3668 requires a couple of changes in the way that packages
3672 A binary <tt>foo</tt> directly uses a library
3673 <tt>libbar</tt> if it is linked with that
3674 library. Other libraries that are needed by
3675 <tt>libbar</tt> are linked indirectly to <tt>foo</tt>,
3676 and the dynamic linker will load them automatically
3677 when it loads <tt>libbar</tt>. Running<prgn>ldd</prgn>
3678 lists all of the libraries used, both directly and
3679 indirectly; but <prgn>objdump</prgn> only lists the
3680 directly linked libraries. A package only needs to
3681 depend on the libraries it is directly linked to,
3682 since the dependencies for those libraries should
3683 automatically pull in the other libraries.
3686 This change does mean a change in the way packages are
3687 build though: currently <prgn>dpkg-shlibdeps</prgn> is
3688 only run on binaries. But since we will now rely on the
3689 libraries depending on the libraries they themselves
3690 need, the packages containing those libraries will
3691 need to run <prgn>dpkg-shlibdeps</prgn> on the
3695 A good example where this would help us is the current
3696 mess with multiple version of the <tt>mesa</tt>
3697 library. With the <prgn>ldd</prgn>-based system, every
3698 package that uses <tt>mesa</tt> needs to add a
3699 dependency on <tt>svgalib|svgalib-dummy</tt> in order
3700 to handle the glide <tt>mesa</tt> variant. With an
3701 <prgn>objdump</prgn>-based system this isn't necessary
3702 anymore and would have saved everyone a lot of work.
3705 Another example: we could update <tt>libimlib</tt>
3706 with a new version that supports a new graphics format
3707 called dgf. If we use the old <prgn>ldd</prgn> method,
3708 every package that uses <tt>libimlib</tt> would need
3709 to be recompiled so it would also depend on
3710 <tt>libdgf</tt> or it wouldn't run due to missing
3711 symbols. However with the new system, packages using
3712 <tt>libimlib</tt> can rely on <tt>libimlib</tt> itself
3713 having the dependency on <tt>libdgf</tt> and wouldn't
3717 used by the compiled binaries and libraries passed through
3718 on its command line.
3722 For each shared library linked to,
3723 <prgn>dpkg-shlibdeps</prgn> needs to know
3724 <list compact="compact">
3725 <item><p>the package containing the library, and</p></item>
3726 <item><p>the library version number,</p></item>
3728 and it scans the following files in this order:
3729 <enumlist compact="compact">
3730 <item><p><tt>debian/shlibs.local</tt></p></item>
3731 <item><p><tt>/etc/dpkg/shlibs.override</tt></p></item>
3732 <item><p><tt>/var/lib/dpkg/info/*.shlibs</tt></p></item>
3733 <item><p><tt>/etc/dpkg/shlibs.default</tt></p></item>
3738 <sect1><heading><em>Who</em> maintains the various
3739 <tt>shlibs</tt> files?
3743 <list compact="compact">
3745 <p><tt>/etc/dpkg/shlibs.default</tt> - the maintainer
3750 <tt>/var/lib/dpkg/info/<var>package</var>.shlibs</tt>
3751 - the maintainer of each package</p>
3755 <tt>/etc/dpkg/shlibs.override</tt> - the local
3756 system administrator</p>
3759 <p><tt>debian/shlibs.local</tt> - the maintainer of
3764 The <tt>shlibs.default</tt> file is managed by
3765 <prgn>dpkg</prgn>. The entries in <tt>shlibs.default</tt>
3766 that are provided by <prgn>dpkg</prgn> are just there to
3767 fix things until the shared library packages all have
3768 <tt>shlibs</tt> files.
3772 <sect1><heading><em>How</em> to use <prgn>dpkg-shlibdeps</prgn> and
3773 the <tt>shlibs</tt> files
3776 <sect2><heading>If your package doesn't provide a shared
3781 Put a call to <prgn>dpkg-shlibdeps</prgn> into your
3782 <tt>debian/rules</tt> file. If your package contains
3783 only binaries (e.g. no scripts) use:
3785 dpkg-shlibdeps debian/tmp/usr/bin/* debian/tmp/usr/sbin/*
3787 If <prgn>dpkg-shlibdeps</prgn> doesn't complain, you're
3788 done. If it does complain you might need to create your
3789 own <tt>debian/shlibs.local</tt> file.</p>
3792 <sect2><heading>If your package provides a shared library
3796 Create a <tt>debian/shlibs</tt> file and let
3797 <tt>debian/rules</tt> install it in the control area:
3799 install -m644 debian/shlibs debian/tmp/DEBIAN
3801 If your package contains additional binaries see above.
3806 <sect1><heading><em>How</em> to write
3807 <tt>debian/shlibs.local</tt>
3811 This file is intended only as a <em>temporary</em> fix if
3812 your binaries depend on a library which doesn't provide
3813 its own <tt>/var/lib/dpkg/info/*.shlibs</tt> file yet.
3817 Let's assume you are packaging a binary <tt>foo</tt>. Your
3818 output in building the package might look like this.
3821 libbar.so.1 => /usr/X11R6/lib/libbar.so.1.0 (0x4001e000)
3822 libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x4002c000)
3823 libc.so.6 => /lib/libc.so.6 (0x40114000)
3824 /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)
3826 And when you ran <prgn>dpkg-shlibdeps</prgn>
3828 $ dpkg-shlibdeps -O foo
3829 dpkg-shlibdeps: warning: unable to find dependency information for shared library libbar
3830 (soname 1, path /usr/X11R6/lib/libbar.so.1.0, dependency field Depends)
3831 shlibs:Depends=libc6 (>= 2.2.1), xlibs (>= 4.0.1-11)
3833 The <prgn>foo</prgn> binary depends on the
3834 <prgn>libbar</prgn> shared library, but no package seems
3835 to provide a <tt>*.shlibs</tt> file in
3836 <tt>/var/lib/dpkg/info/</tt>. Let's determine the package
3842 $ dpkg -S /usr/X11R6/lib/libbar.so.1.0
3843 bar1: /usr/X11R6/lib/libbar.so.1.0
3844 $ dpkg -s bar1 | grep Version
3847 This tells us that the <prgn>bar1</prgn> package, version
3848 1.0-1 is the one we are using. Now we can create our own
3849 <tt>debian/shlibs.local</tt> to temporarily fix the above
3850 problem. Include the following line into your
3851 <tt>debian/shlibs.local</tt> file.
3853 libbar 1 bar1 (>= 1.0-1)
3855 Now your package build should work. As soon as the
3856 maintainer of <prgn>libbar1</prgn> provides a
3857 <tt>shlibs</tt> file, you can remove your
3858 <tt>debian/shlibs.local</tt> file.
3864 <chapt><heading>The Operating System</heading>
3868 <heading>File system hierarchy</heading>
3872 <heading>Linux File system Structure</heading>
3875 The location of all installed files and directories must
3876 comply with the Linux File system Hierarchy Standard
3877 (FHS). The latest version of this document can be found
3878 alongside this manual or on
3879 <url id="http://www.pathname.com/fhs/">.
3880 Specific questions about following the standard may be
3881 asked on <prgn>debian-devel</prgn>, or referred to Daniel
3882 Quinlan, the FHS coordinator, at
3883 <email>quinlan@pathname.com</email>.</p></sect1>
3887 <heading>Site-specific programs</heading>
3890 As mandated by the FHS, packages must not place any
3891 files in <tt>/usr/local</tt>, either by putting them in
3892 the file system archive to be unpacked by <prgn>dpkg</prgn>
3893 or by manipulating them in their maintainer scripts.</p>
3896 However, the package may create empty directories below
3897 <tt>/usr/local</tt> so that the system administrator knows
3898 where to place site-specific files. These directories
3899 should be removed on package removal if they are
3903 Note, that this applies only to directories <em>below</em>
3904 <tt>/usr/local</tt>, not <em>in</em>
3905 <tt>/usr/local</tt>. Packages must not create sub-directories
3906 in the directory <tt>/usr/local</tt> itself, except those listed in
3907 FHS, section 4.5. However, you may create directories
3908 below them as you wish. You must not remove any of the
3909 directories listed in 4.5, even if you created them.</p>
3912 Since <tt>/usr/local</tt> can be mounted read-only from a
3913 remote server, these directories must be created and
3914 removed by the <tt>postinst</tt> and <tt>prerm</tt>
3915 maintainer scripts. These scripts must not fail if either
3916 of these operations fail. (In the future, it will be
3917 possible to tell <prgn>dpkg</prgn> not to unpack files
3918 matching certain patterns, so that the directories can be
3919 included in the <tt>.deb</tt> packages and system
3920 administrators who do not wish these directories in
3921 /usr/local do not need to have them.)</p>
3924 For example, the <prgn>emacs</prgn> package will contain
3926 mkdir -p /usr/local/lib/emacs/site-lisp || true
3928 in the <tt>postinst</tt> script, and
3930 rmdir /usr/local/lib/emacs/site-lisp || true
3931 rmdir /usr/local/lib/emacs || true
3933 in the <tt>prerm</tt> script.</p>
3936 If you do create a directory in <tt>/usr/local</tt> for
3937 local additions to a package, you should ensure that
3938 settings in <tt>/usr/local</tt> take precedence over the
3939 equivalents in <tt>/usr</tt>.</p>
3942 However, because '/usr/local' and its contents are for
3943 exclusive use of the local administrator, a package must
3944 not rely on the presence or absence of files or
3945 directories in '/usr/local' for normal operation.</p>
3948 The <tt>/usr/local</tt> directory itself and all the
3949 subdirectories created by the package should (by default) have
3950 permissions 2775 (group-writable and set-group-id) and be
3951 owned by <tt>root.staff</tt>.</p>
3956 <heading>Users and groups</heading>
3959 The Debian system can be configured to use either plain or
3960 shadow passwords.</p>
3963 Some user ids (UIDs) and group ids (GIDs) are reserved
3964 globally for use by certain packages. Because some packages
3965 need to include files which are owned by these users or
3966 groups, or need the ids compiled into binaries, these ids
3967 must be used on any Debian system only for the purpose for
3968 which they are allocated. This is a serious restriction, and
3969 we should avoid getting in the way of local administration
3970 policies. In particular, many sites allocate users and/or
3971 local system groups starting at 100.</p>
3974 Apart from this we should have dynamically allocated ids,
3975 which should by default be arranged in some sensible
3976 order--but the behavior should be configurable.</p>
3979 Packages other than <tt>base-passwd</tt> must not modify
3980 <tt>/etc/passwd</tt>, <tt>/etc/shadow</tt>,
3981 <tt>/etc/group</tt> or <tt>/etc/gshadow</tt>.</p>
3984 The UID and GID ranges are as follows:
3989 Globally allocated by the Debian project, the
3990 same on every Debian system. These ids will appear in
3991 the <tt>passwd</tt> and <tt>group</tt> files of all
3992 Debian systems, new ids in this range being added
3993 automatically as the <tt>base-passwd</tt> package is
3997 Packages which need a single statically allocated uid
3998 or gid should use one of these; their maintainers
3999 should ask the <tt>base-passwd</tt> maintainer for
4006 Dynamically allocated system users and groups.
4007 Packages which need a user or group, but can have this
4008 user or group allocated dynamically and differently on
4009 each system, should use `<tt>adduser --system</tt>' to
4010 create the group and/or user. <prgn>adduser</prgn>
4011 will check for the existence of the user or group, and
4012 if necessary choose an unused id based on the ranges
4013 specified in <tt>adduser.conf</tt>.</p></item>
4016 <tag>1000-29999:</tag>
4019 Dynamically allocated user accounts. By default
4020 <prgn>adduser</prgn> will choose UIDs and GIDs for
4021 user accounts in this range, though
4022 <tt>adduser.conf</tt> may be used to modify this
4026 <tag>30000-59999:</tag>
4028 <p>Reserved.</p></item>
4031 <tag>60000-64999:</tag>
4034 Globally allocated by the Debian project, but only
4035 created on demand. The ids are allocated centrally and
4036 statically, but the actual accounts are only created
4037 on users' systems on demand.</p>
4040 These ids are for packages which are obscure or which
4041 require many statically-allocated ids. These packages
4042 should check for and create the accounts in
4043 <tt>/etc/passwd</tt> or <tt>/etc/group</tt> (using
4044 <prgn>adduser</prgn> if it has this facility) if
4045 necessary. Packages which are likely to require
4046 further allocations should have a `hole' left after
4047 them in the allocation, to give them room to
4051 <tag>65000-65533:</tag>
4053 <p>Reserved.</p></item>
4058 <p>User `<tt>nobody</tt>.' The corresponding gid refers
4059 to the group `<tt>nogroup</tt>.'</p></item>
4065 <tt>(uid_t)(-1) == (gid_t)(-1)</tt>. NOT TO BE USED,
4066 because it is the error return sentinel value.</p>
4071 <sect id="sysvinit">
4072 <heading>System run levels</heading>
4075 <sect1 id="/etc/init.d">
4076 <heading>Introduction</heading>
4079 The <tt>/etc/init.d</tt> directory contains the scripts
4080 executed by <prgn>init</prgn> at boot time and when init
4081 state (or `runlevel') is changed (see <manref name="init"
4085 There are at least two different, yet functionally
4086 equivalent, ways of handling these scripts. For the sake
4087 of simplicity, this document describes only the symbolic
4088 link method. However, it must not be assumed by maintainer
4089 scripts that this method is being used, and any automated
4090 manipulation of the various runlevel behaviours by
4091 maintainer scripts must be performed using `update-rc.d'
4092 as described below and not by manually installing or
4093 removing symlinks. For information on the
4094 implementation details of the other method, implemented in
4095 the <tt>file-rc</tt> package, please refer to the
4096 documentation of that package.</p>
4099 These scripts are referenced by symbolic links in
4100 the <tt>/etc/rc<var>n</var>.d</tt> directories. When
4101 changing runlevels, <prgn>init</prgn> looks in the
4102 directory <tt>/etc/rc<var>n</var>.d</tt> for the scripts
4103 it should execute, where <var>n</var> is the runlevel that
4104 is being changed to, or `S' for the boot-up scripts.</p>
4107 The names of the links all have the form
4108 <tt>S<var>mm</var><var>script</var></tt> or
4109 <tt>K<var>mm</var><var>script</var></tt> where
4110 <var>mm</var> is a two-digit number and <var>script</var>
4111 is the name of the script (this should be the same as the
4112 name of the actual script in <tt>/etc/init.d</tt>.</p>
4115 When <prgn>init</prgn> changes runlevel first the targets
4116 of the links whose names starting with a <tt>K</tt> are
4117 executed, each with the single argument <tt>stop</tt>,
4118 followed by the scripts prefixed with an <tt>S</tt>, each
4119 with the single argument <tt>start</tt>. The <tt>K</tt>
4120 links are responsible for killing services and the
4121 <tt>S</tt> link for starting services upon entering the
4125 For example, if we are changing from runlevel 2 to
4126 runlevel 3, init will first execute all of the <tt>K</tt>
4127 prefixed scripts it finds in <tt>/etc/rc3.d</tt>, and then
4128 all of the <tt>S</tt> prefixed scripts. The links
4129 starting with <tt>K</tt> will cause the referred-to file
4130 to be executed with an argument of <tt>stop</tt>, and the
4131 <tt>S</tt> links with an argument of <tt>start</tt>.</p>
4134 The two-digit number <var>mm</var> is used to decide which
4135 order to start and stop things in--low-numbered links have
4136 their scripts run first. For example, the <tt>K20</tt>
4137 scripts will be executed before the <tt>K30</tt> scripts.
4138 This is used when a certain service must be started before
4139 another. For example, the name server <prgn>bind</prgn>
4140 might need to be started before the news server
4141 <prgn>inn</prgn> so that <prgn>inn</prgn> can set up its
4142 access lists. In this case, the script that starts
4143 <prgn>bind</prgn> would have a lower number than the
4144 script that starts <prgn>inn</prgn> so that it runs first:
4153 <heading>Writing the scripts</heading>
4156 Packages that include daemons for system services should
4157 place scripts in <tt>/etc/init.d</tt> to start or stop
4158 services at boot time or during a change of runlevel.
4159 These scripts should be named
4160 <tt>/etc/init.d/<var>package</var></tt>, and they should
4161 accept one argument, saying what to do:
4164 <tag><tt>start</tt></tag>
4165 <item><p>start the service,</p></item>
4167 <tag><tt>stop</tt></tag>
4168 <item><p>stop the service,</p></item>
4170 <tag><tt>restart</tt></tag>
4171 <item><p>stop and restart the service,</p></item>
4173 <tag><tt>reload</tt></tag>
4174 <item><p>cause the configuration of the service to be
4175 reloaded without actually stopping and restarting
4176 the service,</p></item>
4178 <tag><tt>force-reload</tt></tag> <item><p>cause the
4179 configuration to be reloaded if the service supports
4180 this, otherwise restart the service.</p></item>
4183 The <tt>start</tt>, <tt>stop</tt>, <tt>restart</tt>, and
4184 <tt>force-reload</tt> options should be supported by all
4185 scripts in <tt>/etc/init.d</tt>, the <tt>reload</tt>
4186 option is optional.</p>
4189 The <tt>init.d</tt> scripts should ensure that they will
4190 behave sensibly if invoked with <tt>start</tt> when the
4191 service is already running, or with <tt>stop</tt> when it
4192 isn't, and that they don't kill unfortunately-named user
4193 processes. The best way to achieve this is usually to use
4194 <prgn>start-stop-daemon</prgn>.</p>
4197 If a service reloads its configuration automatically (as
4198 in the case of <prgn>cron</prgn>, for example), the
4199 <tt>reload</tt> option of the <tt>init.d</tt> script
4200 should behave as if the configuration has been reloaded
4204 These scripts should not fail obscurely when the
4205 configuration files remain but the package has been
4206 removed, as configuration files remain on the system after
4207 the package has been removed. Only when <prgn>dpkg</prgn>
4208 is executed with the <tt>--purge</tt> option will
4209 configuration files be removed. In particular, the init
4210 script itself is usually a configuration file (see
4211 <ref id="init.d notes">), and will remain on the system if
4212 the package is removed but not purged. Therefore, you
4213 should include a <tt>test</tt> statement at the top of the
4216 test -f <var>program-executed-later-in-script</var> || exit 0
4220 Often there are some values in the `<tt>init.d</tt>'
4221 scripts that a system administrator will frequently want
4222 to change. While the scripts are frequently conffiles,
4223 modifying them requires that the administrator merge in
4224 their changes each time the package is upgraded and the
4225 conffile changes. To ease the burden on the system
4226 administrator, such configurable values should not be
4227 placed directly in the script. Instead, they should be
4228 placed in a file in `<tt>/etc/default</tt>', which
4229 typically will have the same base name as the
4230 `<tt>init.d</tt>' script. This extra file can be sourced
4231 by the script when the script runs. It must contain only
4232 variable settings and comments.
4236 To ensure that vital configurable values are always
4237 available, the `<tt>init.d</tt>' script should set default
4238 values for each of the shell variables it uses before
4239 sourcing the <tt>/etc/default/</tt> file. Also, since the
4240 `<tt>/etc/default/</tt>' file is often a conffile, the
4241 `<tt>init.d</tt>' script must behave sensibly without
4242 failing if it is deleted.
4248 <heading>Managing the links</heading>
4251 The program <prgn>update-rc.d</prgn> is provided to make
4252 it easier for package maintainers to arrange for the
4253 proper creation and removal of
4254 <tt>/etc/rc<var>n</var>.d</tt> symbolic links, or their
4255 functional equivalent if another method is being used.
4256 This may be used by maintainers in their packages'
4257 <tt>postinst</tt> and <tt>postrm</tt> scripts.</p>
4260 You must use this script to make changes to
4261 <tt>/etc/rc<var>n</var>.d</tt> and <em>never</em> either
4262 include any <tt>/etc/rc<var>n</var>.d</tt> symbolic links
4263 in the actual archive or manually create or remove the
4264 symbolic links in maintainer scripts. (The latter will
4265 fail if an alternative method of maintaining runlevel
4266 information is being used.)</p>
4269 By default <prgn>update-rc.d</prgn> will start services in
4270 each of the multi-user state runlevels (2, 3, 4, and 5)
4271 and stop them in the halt runlevel (0), the single-user
4272 runlevel (1) and the reboot runlevel (6). The system
4273 administrator will have the opportunity to customize
4274 runlevels by either running <prgn>update-rc.d</prgn>, by
4275 simply adding, moving, or removing the symbolic links in
4276 <tt>/etc/rc<var>n</var>.d</tt> if symbolic links are being
4277 used, or by modifying <tt>/etc/runlevel.conf</tt> if the
4278 <tt>file-rc</tt> method is being used.</p>
4281 To get the default behavior for your package, put in your
4282 <tt>postinst</tt> script
4284 update-rc.d <var>package</var> defaults >/dev/null
4286 and in your <tt>postrm</tt>
4288 if [ purge = "$1" ]; then
4289 update-rc.d <var>package</var> remove >/dev/null
4294 This will use a default sequence number of 20. If it does
4295 not matter when or in which order the script is run, use
4296 this default. If it does, then you should talk to the
4297 maintainer of the <prgn>sysvinit</prgn> package or post to
4298 <tt>debian-devel</tt>, and they will help you choose a
4302 For more information about using <tt>update-rc.d</tt>,
4303 please consult its manpage <manref name="update-rc.d"
4304 section="8">.</p></sect1>
4308 <heading>Boot-time initialization</heading>
4311 There used to be another directory, <tt>/etc/rc.boot</tt>,
4312 which contained scripts which were run once per machine
4313 boot. This has been deprecated in favour of links from
4314 <tt>/etc/rcS.d</tt> to files in <tt>/etc/init.d</tt> as
4315 described in <ref id="/etc/init.d">. Packages must not
4316 place files in <tt>/etc/rc.boot</tt>.</p>
4318 <sect1 id="init.d notes">
4319 <heading>Notes</heading>
4322 <em>Do not</em> include the
4323 <tt>/etc/rc<var>n</var>.d/*</tt> symbolic links in the
4324 <tt>.deb</tt> file system archive! <em>This will cause
4325 problems!</em> You must create them with
4326 <prgn>update-rc.d</prgn>, as above.</p>
4329 <em>Do not</em> include the
4330 <tt>/etc/rc<var>n</var>.d/*</tt> symbolic links in
4331 <prgn>dpkg</prgn>'s conffiles list! <em>This will cause
4332 problems!</em> You should, however, treat the
4333 <tt>/etc/init.d</tt> scripts as configuration files,
4334 either by marking them as conffiles or managing them
4335 correctly in the maintainer scripts (see
4336 <ref id="config files">). (This is important since we want
4337 to give the local system administrator the chance to adapt
4338 the scripts to the local system--e.g., to disable a
4339 service without de-installing the package, or to specify
4340 some special command line options when starting a
4341 service--while making sure her changes aren't lost during
4342 the next package upgrade.)</p>
4346 <heading>Example</heading>
4349 The <prgn>bind</prgn> DNS (nameserver) package wants to
4350 make sure that the nameserver is running in multiuser
4351 runlevels, and is properly shut down with the system. It
4352 puts a script in <tt>/etc/init.d</tt>, naming the script
4353 appropriately <tt>bind</tt>. As you can see, the script
4354 interprets the argument <tt>reload</tt> to send the
4355 nameserver a <tt>HUP</tt> signal (causing it to reload its
4356 configuration); this way the user can say
4357 <tt>/etc/init.d/bind reload</tt> to reload the name
4358 server. The script has one configurable value, which can
4359 be used to pass parameters to the named program at
4367 # Original version by Robert Leslie
4368 # <rob@mars.org>, edited by iwj and cs
4370 test -x /usr/sbin/named || exit 0
4372 # Source defaults file.
4374 if [ -f /etc/default/bind ]; then
4381 echo -n "Starting domain name service: named"
4382 start-stop-daemon --start --quiet --exec /usr/sbin/named \
4387 echo -n "Stopping domain name service: named"
4388 start-stop-daemon --stop --quiet \
4389 --pidfile /var/run/named.pid --exec /usr/sbin/named
4393 echo -n "Restarting domain name service: named"
4394 start-stop-daemon --stop --quiet \
4395 --pidfile /var/run/named.pid --exec /usr/sbin/named
4396 start-stop-daemon --start --verbose --exec /usr/sbin/named \
4400 force-reload|reload)
4401 echo -n "Reloading configuration of domain name service: named"
4402 start-stop-daemon --stop --signal 1 --quiet \
4403 --pidfile /var/run/named.pid --exec /usr/sbin/named
4407 echo "Usage: /etc/init.d/bind {start|stop|restart|reload|force-reload}" >&2
4417 Complementing the above init script is a file
4418 '<tt>/etc/default/bind</tt>', which contains configurable
4419 parameters used by the script.
4423 # Specified parameters to pass to named. See named(8).
4424 # You may uncomment the following line, and edit to taste.
4430 Another example on which to base your <tt>/etc/init.d</tt>
4431 scripts is in <tt>/etc/init.d/skeleton</tt>.</p>
4434 If this package is happy with the default setup from
4435 <prgn>update-rc.d</prgn>, namely an ordering number of 20
4436 and having named running in all runlevels, it can say in
4437 its <tt>postinst</tt>:
4439 update-rc.d bind defaults >/dev/null
4441 And in its <tt>postrm</tt>, to remove the links when the
4444 if [ purge = "$1" ]; then
4445 update-rc.d bind remove >/dev/null
4451 <heading>Cron jobs</heading>
4454 Packages must not modify the configuration file
4455 <tt>/etc/crontab</tt>, and they must not modify the files in
4456 <tt>/var/spool/cron/crontabs</tt>.</p>
4459 If a package wants to install a job that has to be executed
4460 via cron, it should place a file with the name of the
4461 package in one of the following directories:
4467 As these directory names imply, the files within them are
4468 executed on a daily, weekly, or monthly basis,
4469 respectively. The exact times are listed in
4470 <tt>/etc/crontab</tt>.</p>
4473 All files installed in any of these directories must be
4474 scripts (shell scripts, Perl scripts, etc.) so that they can
4475 easily be modified by the local system administrator. In
4476 addition, they should be treated as configuration files.</p>
4479 If a certain job has to be executed more frequently than
4480 daily, the package should install a file
4481 <tt>/etc/cron.d/<var>package-name</var></tt>. This file uses
4482 the same syntax as <tt>/etc/crontab</tt> and is processed by
4483 <prgn>cron</prgn> automatically. The file must also be
4484 treated as a configuration file. (Note, that entries in the
4485 <tt>/etc/cron.d</tt> directory are not handled by
4486 <prgn>anacron</prgn>. Thus, you should only use this
4487 directory for jobs which may be skipped if the system is not
4491 The scripts or crontab entries in these directories should
4492 check if all necessary programs are installed before they
4493 try to execute them. Otherwise, problems will arise when a
4494 package was removed but not purged since configuration files
4495 are kept on the system in this situation.</p>
4499 <heading>Console messages</heading>
4502 This section describes different formats for messages
4503 written to standard output by the <tt>/etc/init.d</tt>
4504 scripts. The intent is to improve the consistency of
4505 Debian's startup and shutdown look and feel.</p>
4508 Please look very careful at the details. We want to get the
4509 messages to look exactly the same way concerning spaces,
4510 punctuation, and case of letters.</p>
4513 Here is a list of overall rules that you should use when you
4514 create output messages. They can be useful if you have a
4515 non-standard message that isn't covered in the sections
4522 Every message should cover one line, start with a
4523 capital letter and end with a period `.'.</p></item>
4528 If you want to express that the computer is working on
4529 something (performing a specific task, not starting or
4530 stopping a program), we use an ``ellipsis'', namely
4531 three dots `...'. Note that we don't insert spaces in
4532 front of or behind the dots. If the task has been
4533 completed we write `done.' and a line feed.</p></item>
4538 Design your messages as if the computer is telling you
4539 what he is doing (let him be polite :-) but don't
4540 mention ``him'' directly. For example, if you think
4543 I'm starting network daemons: nfsd mountd.
4547 Starting network daemons: nfsd mountd.
4548 </example></p></item>
4552 The following formats should be used</p>
4557 <p>when daemons get started.</p>
4560 Use this format if your script starts one or more
4561 daemons. The output should look like this (a single
4562 line, no leading spaces):
4564 Starting <description>: <daemon-1> <daemon-2> <...> <daemon-n>.
4566 The <description> should describe the subsystem
4567 the daemon or set of daemons are part of, while
4568 <daemon-1> up to <daemon-n> denote each
4569 daemon's name (typically the file name of the
4573 For example, the output of /etc/init.d/lpd would look like:
4575 Starting printer spooler: lpd.
4579 This can be achieved by saying
4581 echo -n "Starting printer spooler: lpd"
4582 start-stop-daemon --start --quiet lpd
4585 in the script. If you have more than one daemon to
4586 start, you should do the following:
4588 echo -n "Starting remote file system services:"
4589 echo -n " nfsd"; start-stop-daemon --start --quiet nfsd
4590 echo -n " mountd"; start-stop-daemon --start --quiet mountd
4591 echo -n " ugidd"; start-stop-daemon --start --quiet ugidd
4594 This makes it possible for the user to see what takes
4595 so long and when the final daemon has been
4596 started. You should be careful where to put spaces: In the
4597 example above the system administrator can easily
4598 comment out a line if he don't wants to start a
4599 specific daemon, while the displayed message still
4600 looks good.</p></item>
4604 <p>when something needs to be configured.</p>
4607 If you have to set up different parameters of the
4608 system upon boot up, you should use this format:
4610 Setting <parameter> to `<value>'.
4614 You can use the following echo statement to get the quotes right:
4616 echo "Setting DNS domainname to \`"value"'."
4620 Note that the left quotation mark (`) is different
4621 from the right (').</p></item>
4624 <p>when a daemon is stopped.</p>
4627 When you stop a daemon you should issue a message
4628 similar to the startup message, except that `Starting'
4629 is replaced with `Stopping'.</p>
4632 So stopping the printer daemon will like like this:
4634 Stopping printer spooler: lpd.
4635 </example></p></item>
4638 <p>when something is executed.</p>
4641 There are several examples where you have to run a
4642 program at system startup or shutdown to perform a
4643 specific task. For example, setting the system's clock
4644 via `netdate' or killing all processes when the system
4645 comes down. Your message should like this:
4647 Doing something very useful...done.
4649 You should print the `done.' right after the job has been completed,
4650 so that the user gets informed why he has to wait. You can get this
4653 echo -n "Doing something very useful..."
4657 in your script.</p></item>
4660 <p>when the configuration is reloaded.</p>
4663 When a daemon is forced to reload its configuration
4664 files you should use the following format:
4666 Reloading <daemon's-name> configuration...done.
4667 </example></p></item>
4670 <p>when none of the above rules apply.</p>
4673 If you have to print a message that doesn't fit into
4674 the styles described above, you can use something
4675 appropriate, but please have a look at the overall
4676 rules listed above.</p></item>
4681 <heading>Menus</heading>
4684 Menu entries should follow the current menu policy as
4685 defined in the file <ftpsite>ftp.debian.org</ftpsite> in
4686 <ftppath>/debian/doc/package-developer/menu-policy.text.gz</ftppath>
4687 or your local mirror. In addition, it is included in the
4688 <tt>debian-policy</tt> package.
4692 The Debian <tt>menu</tt> packages provides a unique
4693 interface between packages providing applications and
4694 documents, and <em>menu programs</em> (either X window
4695 managers or text-based menu programs as
4696 <prgn>pdmenu</prgn>).</p>
4699 All packages that provide applications that need not be
4700 passed any special command line arguments for normal
4701 operation should register a menu entry for those
4702 applications, so that users of the <tt>menu</tt> package
4703 will automatically get menu entries in their window
4704 managers, as well in shells like <tt>pdmenu</tt>.</p>
4707 Please refer to the <em>Debian Menu System</em> document
4708 that comes with the <tt>menu</tt> package for information
4709 about how to register your applications and web
4715 <heading>Multimedia handlers</heading>
4718 Packages which provide the ability to view/show/play,
4719 compose, edit or print MIME types should register themselves
4720 as such following the current MIME support policy as defined
4721 in the file found on <ftpsite>ftp.debian.org</ftpsite> in
4722 <ftppath>/debian/doc/package-developer/mime-policy.text.gz</ftppath>
4723 or your local mirror. In addition, it is included in the
4724 <tt>debian-policy</tt> package.
4728 MIME (Multipurpose Internet Mail Extensions, RFC 1521) is a
4729 mechanism for encoding files and data streams and providing
4730 meta-information about them, in particular their type (e.g.
4731 audio or video) and format (e.g. PNG, HTML, MP3).
4735 Registration of MIME type handlers allows programs like mail
4736 user agents and web browsers to to invoke these handlers to
4737 view, edit or display MIME types they don't support
4743 <heading>Keyboard configuration</heading>
4746 To achieve a consistent keyboard configuration (i.e., all
4747 applications interpret a keyboard event the same way) all
4748 programs in the Debian distribution must be configured to
4749 comply with the following guidelines.</p>
4752 Here is a list that contains certain keys and their interpretation:
4755 <tag><tt><--</tt></tag>
4756 <item><p>delete the character to the left of the cursor</p></item>
4758 <tag><tt>Delete</tt></tag>
4759 <item><p>delete the character to the right of the cursor</p></item>
4761 <tag><tt>Control+H</tt></tag>
4762 <item><p>emacs: the help prefix</p></item>
4765 The interpretation of any keyboard events should be independent
4766 of the terminal that's used, be it a virtual console, an X
4767 terminal emulator, an rlogin/telnet session, etc.</p>
4770 The following list explains how the different programs
4771 should be set up to achieve this:</p>
4774 <list compact="compact">
4775 <item><p>`<tt><--</tt>' generates KB_Backspace in
4778 <item><p>`<tt>Delete</tt>' generates KB_Delete in X.</p></item>
4782 X translations are set up to make KB_Backspace
4783 generate ASCII DEL, and to make KB_Delete generate
4784 <tt>ESC [ 3 ~</tt> (this is the vt220 escape code for
4785 the `delete character' key). This must be done by
4786 loading the resources using xrdb on all local X
4787 displays, not using the application defaults, so that
4788 the translation resources used correspond to the
4789 xmodmap settings.</p></item>
4793 The Linux console is configured to make
4794 `<tt><--</tt>' generate DEL, and `Delete' generate
4795 <tt>ESC [ 3 ~</tt> (this is the case at the
4799 X applications are configured so that Backspace
4800 deletes left, and Delete deletes right. Motif
4801 applications already work like this.</p></item>
4803 <item><p>stty erase <tt>^?</tt> .</p></item>
4806 The `xterm' terminfo entry should have <tt>ESC [ 3
4807 ~</tt> for kdch1, just like TERM=linux and
4808 TERM=vt220.</p></item>
4811 Emacs is programmed to map KB_Backspace or the `stty
4812 erase' character to delete-backward-char, and
4813 KB_Delete or kdch1 to delete-forward-char, and
4814 <tt>^H</tt> to help as always.</p></item>
4817 Other applications use the `stty erase' character and
4818 kdch1 for the two delete keys, with ASCII DEL being
4819 `delete previous character' and kdch1 being `delete
4820 character under cursor'.</p></item>
4824 This will solve the problem except for:</p>
4827 <list compact="compact">
4829 Some terminals have a <tt><--</tt> key that cannot
4830 be made to produce anything except <tt>^H</tt>. On
4831 these terminals Emacs help will be unavailable on
4832 <tt>^H</tt> (assuming that the `stty erase' character
4833 takes precedence in Emacs, and has been set
4834 correctly). M-x help or F1 (if available) can be used
4838 Some operating systems use <tt>^H</tt> for stty erase.
4839 However, modern telnet versions and all rlogin
4840 versions propagate stty settings, and almost all UNIX
4841 versions honour stty erase. Where the stty settings
4842 are not propagated correctly things can be made to
4843 work by using stty manually.</p></item>
4846 Some systems (including previous Debian versions) use
4847 xmodmap to arrange for both <tt><--</tt> and Delete
4848 to generate KB_Delete. We can change the behavior
4849 of their X clients via the same X resources that we
4850 use to do it for our own, or have our clients be
4851 configured via their resources when things are the
4852 other way around. On displays configured like this
4853 Delete will not work, but <tt><--</tt>
4857 Some operating systems have different kdch1 settings
4858 in their terminfo for xterm and others. On these
4859 systems the Delete key will not work correctly when
4860 you log in from a system conforming to our policy, but
4861 <tt><--</tt> will.</p></item>
4868 <heading>Environment variables</heading>
4871 A program must not depend on environment variables to get
4872 reasonable defaults. (That's because these environment
4873 variables would have to be set in a system-wide
4874 configuration file like /etc/profile, which is not supported
4878 If a program usually depends on environment variables for its
4879 configuration, the program should be changed to fall back to
4880 a reasonable default configuration if these environment
4881 variables are not present. If this cannot be done easily
4882 (e.g., if the source code of a non-free program is not
4883 available), the program must be replaced by a small
4884 `wrapper' shell script which sets the environment variables
4885 if they are not already defined, and calls the original program.</p>
4888 Here is an example of a wrapper script for this purpose:
4892 BAR=${BAR:-/var/lib/fubar}
4894 exec /usr/lib/foo/foo "$@"
4898 Furthermore, as <tt>/etc/profile</tt> is a configuration
4899 file of the <prgn>base-files</prgn> package, other packages must not
4900 put any environment variables or other commands into that
4905 <heading>Files</heading>
4909 <heading>Binaries</heading>
4912 Two different packages must not install programs with
4913 different functionality but with the same filenames. (The
4914 case of two programs having the same functionality but
4915 different implementations is handled via `alternatives.')
4916 If this case happens, one of the programs must be
4917 renamed. The maintainers should report this to the
4918 developers' mailing and try to find a consensus about
4919 which package will have to be renamed. If a consensus can
4920 not be reached, <em>both</em> programs must be
4924 Generally the following compilation parameters should be used:
4927 CFLAGS = -O2 -Wall # sane warning options vary between programs
4929 install -s # (or use strip on the files in debian/tmp)
4933 Note that by default all installed binaries should be stripped,
4934 either by using the <tt>-s</tt> flag to
4935 <prgn>install</prgn>, or by calling <prgn>strip</prgn> on
4936 the binaries after they have been copied into
4937 <tt>debian/tmp</tt> but before the tree is made into a
4941 The <tt>-N</tt> flag should not be used. On a.out systems
4942 it may have been useful for some very small binaries, but
4943 for ELF it has no good effect.</p>
4946 Debugging symbols are useful for error diagnosis,
4947 investigation of core dumps (which may be submitted by users
4948 in bug reports), or testing and developing the
4949 software. Therefore it is recommended to support building
4950 the package with debugging information through the following
4951 interface: If the environment variable
4952 <tt>DEB_BUILD_OPTIONS</tt> contains the string
4953 <tt>debug</tt>, compile the software with debugging
4954 information (usually this involves adding the <tt>-g</tt>
4955 flag to <tt>CFLAGS</tt>). This allows the generation of a
4956 build tree with debugging information. If the environment
4957 variable <tt>DEB_BUILD_OPTIONS</tt> contains the string
4958 <tt>nostrip</tt>, do not strip the files at installation
4959 time. This allows one to generate a package with debugging
4960 information included. The following makefile snippet is only
4961 an example of how one may test for either condition:
4964 Rationale: Building by default with -g causes more
4965 wasted CPU cycles since the information is stripped away
4966 anyway. The package can by default build without -g if
4967 it also provides a mechanism to easily be rebuilt with
4968 debugging information. This can be done by providing a
4969 "build-debug" make target, or allowing the user to
4970 specify "DEB_BUILD_OPTIONS=debug" in the environment while
4971 compiling that package.
4973 <p>Now this has several added benefits:
4977 It is actually easier to build debugging bins and
4978 libraries this way (no more editing debian/rules
4979 or similar) since it provides a documented way of
4980 getting this type of build.</p>
4984 There will be much less wasted CPU time for the
4985 autobuilders since not having debugging
4986 information (and hence also not having to strip
4987 it) will increase the speed of compiles. This
4988 skips an entire pass of the compiler.
4999 INSTALL_FILE = $(INSTALL) -p -o root -g root -m 644
5000 INSTALL_PROGRAM = $(INSTALL) -p -o root -g root -m 755
5001 INSTALL_SCRIPT = $(INSTALL) -p -o root -g root -m 755
5002 INSTALL_DIR = $(INSTALL) -p -d -o root -g root -m 755
5004 ifneq (,$(findstring debug,$(DEB_BUILD_OPTIONS)))
5007 ifeq (,$(findstring nostrip,$(DEB_BUILD_OPTIONS)))
5008 INSTALL_PROGRAM += -s
5012 Please note that the above example is merely informative,
5013 and is not a policy mandate. You may have to massage this
5014 example in order to make it work for your package.
5019 It is up to the package maintainer to decide what
5020 compilation options are best for the package. Certain
5021 binaries (such as computationally-intensive programs) will
5022 function better with certain flags (<tt>-O3</tt>, for
5023 example); feel free to use them. Please use good judgment
5024 here. Don't use flags for the sake of it; only use them
5025 if there is good reason to do so. Feel free to override
5026 the upstream author's ideas about which compilation
5027 options are best--they are often inappropriate for our
5028 environment.</p></sect>
5032 <heading>Libraries</heading>
5035 All libraries must have a shared version in the lib
5036 package and a static version in the lib-dev package. The
5037 shared version must be compiled with <tt>-fPIC</tt>, and
5038 the static version must not be. In other words, each
5039 <tt>*.c</tt> file will need to be compiled twice.</p>
5042 You must specify the gcc option <tt>-D_REENTRANT</tt>
5043 when building a library (either static or shared) to make
5044 the library compatible with LinuxThreads.</p>
5047 Note that all installed shared libraries should be
5050 strip --strip-unneeded <your-lib>
5052 (The option `--strip-unneeded' makes <tt>strip</tt> remove
5053 only the symbols which aren't needed for relocation
5054 processing.) Shared libraries can function perfectly well
5055 when stripped, since the symbols for dynamic linking are
5056 in a separate part of the ELF object file.</p>
5059 Note that under some circumstances it may be useful to
5060 install a shared library unstripped, for example when
5061 building a separate package to support debugging.
5065 An ever increasing number of packages are using libtool to
5066 do their linking. The latest GNU libtools (>= 1.3a) can take
5067 advantage of the metadata in the installed libtool archive
5068 files (`*.la'). The main advantage of libtool's .la files is
5069 that it allows libtool to store and subsequently access
5070 metadata with respect to the libraries it builds. libtool
5071 will search for those files, which contain a lot of useful
5072 information about a library (e.g. dependency libraries for
5073 static linking). Also, they're <em>essential</em> for
5074 programs using libltdl.
5078 Certainly libtool is fully capable of linking against shared
5079 libraries which don't have .la files, but being a mere shell
5080 script it can add considerably to the build time of a
5081 libtool using package if that shell-script has to derive all
5082 this information from first principles for each library every
5083 time it is linked. With the advent of libtool-1.4 (and to a
5084 lesser extent libtool-1.3), the .la files will also store
5085 information about inter-library dependencies which cannot
5086 necessarily be derived after the .la file is deleted.
5090 Packages that use libtool to create shared libraries should
5091 include the <em>.la</em> files in the <em>-dev</em>
5092 packages, with the exception that if the package relies on
5093 libtool's <em>libltdl</em> library, in which case the .la
5094 files must go in the run-time library package. This is a
5095 good idea in general, and especially for static linking
5100 You must make sure that you use only released versions of
5101 shared libraries to build your packages; otherwise other
5102 users will not be able to run your binaries
5103 properly. Producing source packages that depend on
5104 unreleased compilers is also usually a bad
5111 <heading>Shared libraries</heading>
5114 Packages involving shared libraries should be split up
5115 into several binary packages.</p>
5118 For a straightforward library which has a development
5119 environment and a runtime kit including just shared
5120 libraries you need to create two packages:
5121 <tt><var>libraryname</var><var>soname</var></tt>
5122 (<var>soname</var> is the shared object name of the shared
5123 library--it's the thing that has to match exactly between
5124 building an executable and running it for the dynamic
5125 linker to be able run the program; usually the
5126 <var>soname</var> is the major number of the library) and
5127 <tt><var>libraryname</var><var>soname</var>-dev</tt>.</p>
5130 If you prefer only to support one development version at a
5131 time you may name the development package
5132 <tt><var>libraryname</var>-dev</tt>; otherwise you may
5133 wish to use <prgn>dpkg</prgn>'s conflicts mechanism to
5134 ensure that the user only installs one development version
5135 at a time (after all, different development versions are
5136 likely to have the same header files in them, causing a
5137 filename clash if both are installed). Typically the
5138 development version should also have an exact version
5139 dependency on the runtime library, to make sure that
5140 compilation and linking happens correctly.</p>
5143 Packages which use the shared library should have a
5144 dependency on the name of the shared library package,
5145 <tt><var>libraryname</var><var>soname</var></tt>. When
5146 the <var>soname</var> changes you can have both versions
5147 of the library installed while moving from the old library
5151 If your package has some run-time support programs which
5152 use the shared library you must not put them in
5153 the shared library package. If you do that then you won't
5154 be able to install several versions of the shared library
5155 without getting filename clashes. Instead, either create
5156 a third package for the runtime binaries (this package
5157 might typically be named
5158 <tt><var>libraryname</var>-runtime</tt>--note the absence
5159 of the <var>soname</var> in the package name) or if the
5160 development package is small include them in there.</p>
5163 If you have several shared libraries built from the same
5164 source tree you may lump them all together into a single
5165 shared library package, provided that you change all their
5166 <var>soname</var>s at once (so that you don't get filename
5167 clashes if you try to install different versions of the
5168 combined shared libraries package).</p>
5171 You should follow the directions in the <em>Debian Packaging
5172 Manual</em> for putting the shared library in its package,
5173 and you must include a <tt>shlibs</tt> control area
5174 file with details of the dependencies for packages which
5175 use the library.</p>
5178 Shared libraries should not be installed
5179 executable, since <prgn>ld.so</prgn> does not require this
5180 and trying to execute a shared library results in a core
5185 <heading>Scripts</heading>
5188 All command scripts, including the package maintainer
5189 scripts inside the package and used by <prgn>dpkg</prgn>,
5190 should have a <tt>#!</tt> line naming the shell to be used
5191 to interpret them.</p>
5194 In the case of Perl scripts this should be
5195 <tt>#!/usr/bin/perl</tt>.</p>
5198 Shell scripts (<prgn>sh</prgn> and <prgn>bash</prgn>)
5199 should almost certainly start with <tt>set -e</tt> so that
5200 errors are detected. Every script should use
5201 <tt>set -e</tt> or check the exit status of <em>every</em>
5205 The standard shell interpreter `<tt>/bin/sh</tt>' can be a
5206 symbolic link to any POSIX compatible shell, if <tt>echo
5207 -n</tt> does not generate a newline.
5210 Debian policy specifies POSIX behavior for /bin/sh, but
5211 echo -n has widespread use in the Linux community
5212 (including especially debian policy, the linux kernel
5213 source, many debian scripts, etc.). This echo -n
5214 mechanism is valid but not required under POSIX, hence
5215 this explicit addition. Also, rumour has it that this
5216 shall be mandated under the LSB anyway.
5220 specifying `<tt>/bin/sh</tt>' as interpreter should only
5221 use POSIX features. If a script requires non-POSIX
5222 features from the shell interpreter, the appropriate shell
5223 must be specified in the first line of the script (e.g.,
5224 `<tt>#!/bin/bash</tt>') and the package must depend on the
5225 package providing the shell (unless the shell package is
5226 marked `Essential', e.g., in the case of
5231 You may wish to restrict your script to POSIX features when possible so
5232 that it may use <tt>/bin/sh</tt> as its interpreter. If
5233 your script works with <prgn>ash</prgn>, it's probably
5234 POSIX compliant, but if you are in doubt, use
5235 <tt>/bin/bash</tt>.</p>
5238 Perl scripts should check for errors when making any
5239 system calls, including <tt>open</tt>, <tt>print</tt>,
5240 <tt>close</tt>, <tt>rename</tt> and <tt>system</tt>.</p>
5243 <prgn>csh</prgn> and <prgn>tcsh</prgn> should be avoided
5244 as scripting languages. See <em>Csh Programming
5245 Considered Harmful</em>, one of the <tt>comp.unix.*</tt>
5246 FAQs. It can be found on
5247 <url id="http://language.perl.com/versus/csh.whynot">, or
5248 <url id="http://www.cpan.org/doc/FMTEYEWTK/versus/csh.whynot">
5249 or even on <ftpsite>ftp.cpan.org</ftpsite>
5250 <ftppath>/pub/perl/CPAN/doc/FMTEYEWTK/versus/csh.whynot</ftppath>.
5251 If an upstream package comes with <prgn>csh</prgn> scripts
5252 then you must make sure that they start with
5253 <tt>#!/bin/csh</tt> and make your package depend on the
5254 <prgn>c-shell</prgn> virtual package.</p>
5257 Any scripts which create files in world-writeable
5258 directories (e.g., in <tt>/tmp</tt>) must use a
5259 mechanism which will fail if a file with the same name
5263 The Debian base distribution provides the
5264 <prgn>tempfile</prgn> and <prgn>mktemp</prgn> utilities
5265 for use by scripts for this purpose.</p></sect>
5269 <heading>Symbolic links</heading>
5272 In general, symbolic links within a top-level directory
5273 should be relative, and symbolic links pointing from one
5274 top-level directory into another should be absolute. (A
5275 top-level directory is a sub-directory of the root
5279 In addition, symbolic links should be specified as short
5280 as possible, i.e., link targets like `foo/../bar' are
5284 Note that when creating a relative link using
5285 <prgn>ln</prgn> it is not necessary for the target of the
5286 link to exist relative to the working directory you're
5287 running <prgn>ln</prgn> from; nor is it necessary to
5288 change directory to the directory where the link is to be
5289 made. Simply include the string that should appear as the
5290 target of the link (this will be a pathname relative to
5291 the directory in which the link resides) as the first
5292 argument to <prgn>ln</prgn>.</p>
5295 For example, in your <prgn>Makefile</prgn> or
5296 <tt>debian/rules</tt>, do things like:
5298 ln -fs gcc $(prefix)/bin/cc
5299 ln -fs gcc debian/tmp/usr/bin/cc
5300 ln -fs ../sbin/sendmail $(prefix)/bin/runq
5301 ln -fs ../sbin/sendmail debian/tmp/usr/bin/runq
5305 A symbolic link pointing to a compressed file should
5306 always have the same file extension as the referenced
5307 file. (For example, if a file `<tt>foo.gz</tt>' is
5308 referenced by a symbolic link, the filename of the link
5309 has to end with `<tt>.gz</tt>' too, as in
5310 `bar.gz.')</p></sect>
5314 <heading>Device files</heading>
5317 Packages must not include device files in the package file
5321 If a package needs any special device files that are not
5322 included in the base system, it must call
5323 <prgn>MAKEDEV</prgn> in the <tt>postinst</tt> script,
5324 after asking the user for permission to do so.</p>
5327 Packages must not remove any device files in the
5328 <tt>postrm</tt> or any other script. This is left to the
5329 system administrator.</p>
5332 Debian uses the serial devices
5333 <tt>/dev/ttyS*</tt>. Programs using the old
5334 <tt>/dev/cu*</tt> devices should be changed to use
5335 <tt>/dev/ttyS*</tt>.</p>
5338 <sect id="config files">
5339 <heading>Configuration files</heading>
5341 <heading>Definitions</heading>
5344 <tag>configuration file</tag>
5346 A file that affects the operation of program, or
5347 provides site- or host-specific information, or
5348 otherwise customizes the behavior of program.
5349 Typically, configuration files are intended to be
5350 modified by the system administrator (if needed or
5351 desired) to conform to local policy or provide more
5352 useful site-specific behavior.</p>
5355 <tag><tt>conffile</tt></tag>
5357 A file listed in a package's <tt>conffiles</tt>
5358 file, and is treated specially by <prgn>dpkg</prgn>
5359 (see the <em>Debian Packaging Manual</em>).</p>
5365 The distinction between these two is important; they are
5366 not interchangeable concepts. Almost all
5367 <tt>conffiles</tt> are configuration files, but many
5368 configuration files are not <tt>conffiles</tt>.</p>
5371 Note that a script that embeds configuration information
5372 (such as most of the files in <tt>/etc/init.d</tt> and
5373 <tt>/etc/cron.{daily,weekly,monthly}</tt>) is de-facto a
5374 configuration file and should be treated as such.</p>
5378 <heading>Location</heading>
5380 Any configuration files created or used by your package
5381 must reside in <tt>/etc</tt>. If there are several you
5382 should consider creating a subdirectory of <tt>/etc</tt>
5383 named after your package.</p>
5386 If your package creates or uses configuration files
5387 outside of <tt>/etc</tt>, and it is not feasible to modify
5388 the package to use the <tt>/etc</tt>, you should still put
5389 the files in <tt>/etc</tt> and create symbolic links to
5390 those files from the location that the package
5395 <heading>Behavior</heading>
5397 Configuration file handling must conform to the following
5401 <p>local changes must be preserved during a package
5405 <p>configuration files must be preserved when the
5406 package is removed, and only deleted when the
5407 package is purged.</p>
5412 The easy way to achieve this behavior is to make the
5413 configuration file a <tt>conffile</tt>. This is
5414 appropriate only if it is possible to distribute a default
5415 version that will work for most installations, although
5416 some system administrators may choose to modify it. This
5417 implies that the default version will be part of the
5418 package distribution, and must not be modified by the
5419 maintainer scripts during installation (or at any other
5424 In order to ensure that local changes are preserved
5425 correctly, no package may contain or make hard links to
5429 Rationale: There are two problems with hard links.
5430 The first is that some editors break the link while
5431 editing one of the files, so that the two files may
5432 unwittingly become different. The second is that
5433 <prgn>dpkg</prgn> might break the hard link while
5434 upgrading <tt>conffile</tt>s.
5439 The other way to do it is via the maintainer scripts.
5440 In this case, the configuration file must not be listed as
5441 a <tt>conffile</tt> and must not be part of the package
5442 distribution. If the existence of a file is required for
5443 the package to be sensibly configured it is the
5444 responsibility of the package maintainer to write scripts
5445 which correctly create, update, maintain and
5446 remove-on-purge the file. These scripts must be idempotent
5447 (i.e., must work correctly if <prgn>dpkg</prgn> needs to
5448 re-run them due to errors during installation or removal),
5449 must cope with all the variety of ways <prgn>dpkg</prgn>
5450 can call maintainer scripts, must not overwrite or
5451 otherwise mangle the user's configuration without asking,
5452 must not ask unnecessary questions (particularly during
5453 upgrades), and otherwise be good citizens.</p>
5456 The scripts are not required to configure every possible option for
5457 the package, but only those necessary to get the package
5458 running on a given system. Ideally the sysadmin should not
5459 have to do any configuration other than that done
5460 (semi-)automatically by the <tt>postinst</tt> script.</p>
5463 A common practice is to create a script called
5464 <tt><var>package</var>-configure</tt> and have the
5465 package's <tt>postinst</tt> call it if and only if the
5466 configuration file does not already exist. In certain
5467 cases it is useful for there to be an example or template
5468 file which the maintainer scripts use. Such files should
5469 be in <tt>/usr/share/doc</tt> if they are examples or
5470 <tt>/usr/lib</tt> if they are templates, and should be
5471 perfectly ordinary <prgn>dpkg</prgn>-handled files
5472 (<em>not</em> <tt>conffiles</tt>).</p>
5475 These two styles of configuration file handling must
5476 not be mixed, for that way lies madness:
5477 <prgn>dpkg</prgn> will ask about overwriting the file
5478 every time the package is upgraded.</p>
5483 <heading>Sharing configuration files</heading>
5485 Packages which specify the same file as
5486 `<tt>conffile</tt>' must be tagged as <em>conflicting</em>
5491 The maintainer scripts must not alter the conffile of
5492 <em>any</em> package, including the one the scripts belong
5496 If two or more packages use the same configuration file
5497 and it is reasonable for both to be installed at the same
5498 time, one of these packages must be defined as
5499 <em>owner</em> of the configuration file, i.e., it will be
5500 the package to list that distributes the file and lists it
5501 as a <tt>conffile</tt>. Other packages that use the
5502 configuration file must depend on the owning package if
5503 they require the configuration file to operate. If the
5504 other package will use the configuration file if present,
5505 but is capable of operating without it, no dependency need
5509 If it is desirable for two or more related packages to
5510 share a configuration file <em>and</em> for all of the
5511 related packages to be able to modify that configuration
5512 file, then the following should be done:
5516 have one of the related packages (the "core"
5517 package) manage the configuration file with
5518 maintainer scripts as described in the previous
5522 the core package should also provide a program that
5523 the other packages may use to modify the
5524 configuration file.</p>
5528 the related packages must use the provided program
5529 to make any modifications to the configuration file.
5530 They should either depend on the core package to
5531 guarantee that the configuration modifier program is
5532 available or accept gracefully that they cannot
5533 modify the configuration file if it is not.</p>
5538 Sometimes it's appropriate to create a new package which
5539 provides the basic infrastructure for the other packages
5540 and which manages the shared configuration files. (Check
5541 out the <tt>sgml-base</tt> package as an example.)</p>
5545 <heading>User configuration files ("dotfiles")</heading>
5548 Files in <tt>/etc/skel</tt> will automatically be copied
5549 into new user accounts by <prgn>adduser</prgn>. They
5550 should not be referenced there by any program.</p>
5553 Therefore, if a program needs a dotfile to exist in
5554 advance in <tt>$HOME</tt> to work sensibly, that dotfile
5555 should be installed in <tt>/etc/skel</tt> (and listed in
5556 conffiles, if it is not generated and modified dynamically
5557 by the package's installation scripts).</p>
5560 However, programs that require dotfiles in order to
5561 operate sensibly (dotfiles that they do not create
5562 themselves automatically, that is) are a bad thing, and
5563 programs should be configured by the Debian default
5564 installation as close to normal as possible.</p>
5567 Therefore, if a program in a Debian package needs to be
5568 configured in some way in order to operate sensibly that
5569 configuration should be done in a site-wide global
5570 configuration file elsewhere in <tt>/etc</tt>. Only if the
5571 program doesn't support a site-wide default configuration
5572 and the package maintainer doesn't have time to add it
5573 may a default per-user file be placed in
5574 <tt>/etc/skel</tt>.</p>
5577 <tt>/etc/skel</tt> should be as empty as we can make it.
5578 This is particularly true because there is no easy
5579 mechanism for ensuring that the appropriate dotfiles are
5580 copied into the accounts of existing users when a package
5586 <heading>Log files</heading>
5588 The traditional approach to log files has been to set up ad
5589 hoc log rotation schemes using simple shell scripts and
5590 cron. While this approach is highly customizable, it
5591 requires quite a lot of sysadmin work. Even though the
5592 original Debian system helped a little by automatically
5593 installing a system which can be used as a template, this
5594 was deemed not enough.
5598 A better scheme is to use logrotate, a GPL'd program
5599 developed by Red Hat, which centralizes log management. It
5600 has both a configuration file (<tt>/etc/logrotate.conf</tt>)
5601 and a directory where packages can drop logrotation info
5602 (<tt>/etc/logrotate.d</tt>).
5606 Log files should usually be named
5607 <tt>/var/log/<var>package</var>.log</tt>. If you have many
5608 log files, or need a separate directory for permissions
5609 reasons (<tt>/var/log</tt> is writable only by
5610 <tt>root</tt>), you should usually create a directory named
5611 <tt>/var/log/<var>package</var></tt>.</p>
5614 Log files must be rotated occasionally so
5615 that they don't grow indefinitely; the best way to do this
5616 is to drop a script into the directory
5617 <tt>/etc/logrotate.d</tt> and use the facilities provided by
5618 logrotate. Here is a good example for a logrotate config
5619 file (for more information see <manref name="logrotate"
5627 /etc/init.d/foo force-reload
5631 Which rotates all files under `/var/log/foo', saves 12
5632 compressed generations, and sends a HUP signal at the end of
5638 Log files should be removed when the package is
5639 purged (but not when it is only removed), by checking the
5640 argument to the <tt>postrm</tt> script (see the <em>Debian
5641 Packaging Manual</em> for details).</p>
5646 <heading>Permissions and owners</heading>
5649 The rules in this section are guidelines for general use.
5650 If necessary you may deviate from the details below.
5651 However, if you do so you must make sure that what is done
5652 is secure and you should try to be as consistent as possible
5653 with the rest of the system. You should probably also
5654 discuss it on <prgn>debian-devel</prgn> first.</p>
5657 Files should be owned by <tt>root.root</tt>, and made
5658 writable only by the owner and universally readable (and
5659 executable, if appropriate).</p>
5662 Directories should be mode 755 or (for group-writability)
5663 mode 2775. The ownership of the directory should be
5664 consistent with its mode--if a directory is mode 2775, it
5665 should be owned by the group that needs write access to
5669 Setuid and setgid executables should be mode 4755 or 2755
5670 respectively, and owned by the appropriate user or group.
5671 They should not be made unreadable (modes like 4711 or
5672 2711 or even 4111); doing so achieves no extra security,
5673 because anyone can find the binary in the freely available
5674 Debian package--it is merely inconvenient. For the same
5675 reason you should not restrict read or execute permissions
5676 on non-set-id executables.</p>
5679 Some setuid programs need to be restricted to particular
5680 sets of users, using file permissions. In this case they
5681 should be owned by the uid to which they are set-id, and
5682 by the group which should be allowed to execute them.
5683 They should have mode 4754; there is no point in making
5684 them unreadable to those users who must not be allowed to
5688 You must not arrange that the system administrator can only
5689 reconfigure the package to correspond to their local
5690 security policy by changing the permissions on a binary.
5691 Ordinary files installed by <prgn>dpkg</prgn> (as opposed
5692 to conffiles and other similar objects) have their
5693 permissions reset to the distributed permissions when the
5694 package is reinstalled. Instead you should consider (for
5695 example) creating a group for people allowed to use the
5696 program(s) and making any setuid executables executable
5697 only by that group.</p>
5700 If you need to create a new user or group for your package
5701 there are two possibilities. Firstly, you may need to
5702 make some files in the binary package be owned by this
5703 user or group, or you may need to compile the user or
5704 group id (rather than just the name) into the binary
5705 (though this latter should be avoided if possible, as in
5706 this case you need a statically allocated id).</p>
5709 If you need a statically allocated id, you must ask for a
5710 user or group id from the base system
5711 maintainer, and must not release the package until you
5712 have been allocated one. Once you have been allocated one
5713 you must make the package depend on a version of the base
5714 system with the id present in <tt>/etc/passwd</tt> or
5715 <tt>/etc/group</tt>, or alternatively arrange for your
5716 package to create the user or group itself with the
5717 correct id (using <tt>adduser</tt>) in its pre- or
5718 post-installation script (the latter is to be preferred if
5719 it is possible).</p>
5722 On the other hand, the program might be able to determine the
5723 uid or gid from the group name at runtime, so that a
5724 dynamic id can be used. In this case you should choose an
5725 appropriate user or group name, discussing this on
5726 <prgn>debian-devel</prgn> and checking with the base
5727 system maintainer that it is unique and that they do not
5728 wish you to use a statically allocated id instead. When
5729 this has been checked you must arrange for your package to
5730 create the user or group if necessary using
5731 <prgn>adduser</prgn> in the pre- or post-installation
5732 script (again, the latter is to be preferred if it is
5736 Note that changing the numeric value of an id associated with a name
5737 is very difficult, and involves searching the file system for all
5738 appropriate files. You need to think carefully whether a static or
5739 dynamic id is required, since changing your mind later will cause
5745 <heading>Customized programs</heading>
5747 <sect id="arch-spec">
5748 <heading>Architecture specification strings</heading>
5751 If a program needs to specify an <em>architecture specification
5752 string</em> in some place, the following format should be used:
5754 <arch>-<os>
5756 where `<arch>' is one of the following: i386, alpha, arm, m68k,
5757 powerpc, sparc and `<os>' is one of: linux, gnu. Use
5758 of <em>gnu</em> in this string is reserved for the GNU/Hurd
5759 operating system.</p>
5761 Note, that we don't want to use `<arch>-debian-linux'
5762 to apply to the rule `architecture-vendor-os' since this
5763 would make our programs incompatible to other Linux
5764 distributions. Also note, that we don't use
5765 `<arch>-unknown-linux', since the `unknown' does not
5766 look very good.</p></sect>
5770 <heading>Daemons</heading>
5773 The configuration files <tt>/etc/services</tt>,
5774 <tt>/etc/protocols</tt>, and <tt>/etc/rpc</tt> are managed
5775 by the <prgn>netbase</prgn> package and may not be modified
5776 by other packages.</p>
5779 If a package requires a new entry in one of these files, the
5780 maintainer should get in contact with the
5781 <prgn>netbase</prgn> maintainer, who will add the entries
5782 and release a new version of the <prgn>netbase</prgn>
5786 The configuration file <tt>/etc/inetd.conf</tt> must not be
5787 modified by the package's scripts except via the
5788 <prgn>update-inetd</prgn> script or the
5789 <prgn>DebianNet.pm</prgn> Perl module.</p>
5792 If a package wants to install an example entry into
5793 <tt>/etc/inetd.conf</tt>, the entry must be preceded with
5794 exactly one hash character (<tt>#</tt>). Such lines are
5795 treated as `commented out by user' by the
5796 <prgn>update-inetd</prgn> script and are not changed or
5797 activated during a package updates.</p></sect>
5801 <heading>Using pseudo-ttys and modifying wtmp, utmp and lastlog</heading>
5804 Some programs need to create pseudo-ttys. This should be done
5805 using Unix98 ptys if the C library supports it. The resulting
5806 program must not be installed setuid root, unless that
5807 is required for other functionality.
5811 The files <tt>/var/run/utmp</tt>, <tt>/var/log/wtmp</tt> and
5812 <tt>/var/log/lastlog</tt> must be installed writeable by
5813 group utmp. Programs who need to modify those files must
5814 be installed setgid utmp.
5819 <heading>Editors and pagers</heading>
5822 Some programs have the ability to launch an editor or pager
5823 program to edit or display a text document. Since there are
5824 lots of different editors and pagers available in the Debian
5825 distribution, the system administrator and each user should
5826 have the possibility to choose his/her preferred editor and
5830 In addition, every program should choose a good default
5831 editor/pager if none is selected by the user or system
5835 Thus, every program that launches an editor or pager must
5836 use the EDITOR or PAGER environment variables to determine
5837 the editor/pager the user wants to get started. If these
5838 variables are not set, the programs <tt>/usr/bin/editor</tt>
5839 and <tt>/usr/bin/pager</tt> should be used, respectively.</p>
5842 These two files are managed through `alternatives.' That is,
5843 every package providing an editor or pager must call the
5844 <prgn>update-alternatives</prgn> script to register these
5848 If it is very hard to adapt a program to make us of the
5849 EDITOR and PAGER variables, that program may be configured
5850 to use <tt>/usr/bin/sensible-editor</tt> and
5851 <tt>/usr/bin/sensible-pager</tt> as editor or pager program,
5852 respectively. These are two scripts provided in the Debian
5853 base system that check the EDITOR and PAGER variables and
5854 launch the appropriate program or fall back to
5855 <tt>/usr/bin/editor</tt> and <tt>/usr/bin/pager</tt>,
5859 A program may also use the VISUAL environment variable to
5860 determine the user's choice of editor. If it exists, it
5861 should take precedence over EDITOR. This is in fact what
5862 <tt>/usr/bin/sensible-editor</tt> does.</p>
5865 It is not required for a package to depend on
5866 `editor' and `pager', nor is it required for a package to
5867 provide such virtual packages.
5870 The Debian base system already provides an editor and
5879 <sect id="web-appl">
5880 <heading>Web servers and applications</heading>
5883 This section describes the locations and URLs that should
5884 be used by all web servers and web application in the Debian
5890 <p>Cgi-bin executable files are installed in the
5893 /usr/lib/cgi-bin/<cgi-bin-name>
5895 and should be referred to as
5897 http://localhost/cgi-bin/<cgi-bin-name>
5898 </example></p></item>
5901 <item><p>Access to html documents</p>
5904 Html documents for a package are stored in
5905 <tt>/usr/share/doc/<var>package</var></tt> but should
5906 be accessed via symlinks as
5907 <tt>/usr/doc/<var>package</var></tt><footnote> for
5908 backward compatibility, see <ref id="usrdoc"></footnote>
5909 and can be referred to as
5911 http://localhost/doc/<package>/<filename>
5912 </example></p></item>
5915 <item><p>Web Document Root</p>
5918 Web Applications should try to avoid storing files in
5919 the Web Document Root. Instead they should use the
5920 /usr/share/doc/<package> directory for documents and
5921 register the Web Application via the menu package. If
5922 access to the web-root is unavoidable then use
5926 as the Document Root. This might be just a
5927 symbolic link to the location where the sysadmin has
5928 put the real document root.</p>
5931 </enumlist></p></sect>
5935 <heading>Mail transport, delivery and user agents</heading>
5938 Debian packages which process electronic mail, whether
5939 mail-user-agents (MUAs) or mail-transport-agents (MTAs),
5940 must make sure that they are compatible with the
5941 configuration decisions below. Failure to do this may
5942 result in lost mail, broken <tt>From:</tt> lines, and other
5943 serious brain damage!</p>
5946 The mail spool is <tt>/var/spool/mail</tt> and the interface
5947 to send a mail message is <tt>/usr/sbin/sendmail</tt> (as
5948 per the FHS). The mail spool is part of the base system
5949 and not part of the MTA package.</p>
5952 All Debian MUAs, MTAs, MDAs and other mailbox accessing
5953 programs (like IMAP daemons) must lock the mailbox in an
5954 NFS-safe way. This means that <tt>fcntl()</tt> locking must
5955 be combined with dot locking. To avoid deadlocks, a
5956 program should use <tt>fcntl()</tt> first and dot locking
5957 after this or alternatively implement the two locking
5958 methods in a non blocking way<footnote>
5960 If it is not possible to establish both locks, the
5961 system shouldn't wait for the second lock to be
5962 established, but remove the first lock, wait a (random)
5963 time, and start over locking again.</p>
5964 </footnote>. Using the functions <tt>maillock</tt> and
5965 <tt>mailunlock</tt> provided by the
5966 <tt>liblockfile*</tt><footnote>
5968 <tt>liblockfile</tt> version >>1.01</p>
5969 </footnote> packages is the recommended way to realize this.
5973 Mailboxes are generally 660 <tt><var>user</var>.mail</tt>
5974 unless the user has chosen otherwise. A MUA may remove a
5975 mailbox (unless it has nonstandard permissions) in which
5976 case the MTA or another MUA must recreate it if needed.
5977 Mailboxes must be writable by group mail.</p>
5980 The mail spool is 2775 <tt>root.mail</tt>, and MUAs should
5981 be setgid mail to do the locking mentioned above (and
5982 must obviously avoid accessing other users' mailboxes
5983 using this privilege).</p>
5986 <tt>/etc/aliases</tt> is the source file for the system mail
5987 aliases (e.g., postmaster, usenet, etc.)--it is the one
5988 which the sysadmin and <tt>postinst</tt> scripts may edit.
5989 After <tt>/etc/aliases</tt> is edited the program or human
5990 editing it must call <prgn>newaliases</prgn>. All MTA
5991 packages must come with a <prgn>newaliases</prgn> program,
5992 even if it does nothing, but older MTA packages do not do
5993 this so programs should not fail if <prgn>newaliases</prgn>
5994 cannot be found.</p>
5997 The convention of writing <tt>forward to
5998 <var>address</var></tt> in the mailbox itself is not
5999 supported. Use a <tt>.forward</tt> file instead.</p>
6002 The <prgn>rmail</prgn> program used by UUCP
6003 for incoming mail should be <tt>/usr/sbin/rmail</tt>.
6004 Likewise, <prgn>rsmtp</prgn>, for receiving
6005 batch-SMTP-over-UUCP, should be <tt>/usr/sbin/rsmtp</tt> if it
6009 If you need to know what name to use (for example) on
6010 outgoing news and mail messages which are generated locally,
6011 you should use the file <tt>/etc/mailname</tt>. It will
6012 contain the portion after the username and <tt>@</tt> (at)
6013 sign for email addresses of users on the machine (followed
6017 A package should check for the existence of this file. If
6018 it exists it should use it without comment. (An MTA's
6019 prompting configuration script may wish to prompt the user
6020 even if it finds this file exists.) If it does not exist it
6021 should prompt the user for the value and store it in
6022 <tt>/etc/mailname</tt> as well as using it in the package's
6023 configuration. The prompt should make it clear that the
6024 name will not just be used by that package. For example, in
6025 this situation the INN package says:
6027 Please enter the `mail name' of your system. This is the
6028 hostname portion of the address to be shown on outgoing
6029 news and mail messages. The default is
6030 <var>syshostname</var>, your system's host name. Mail
6031 name [`<var>syshostname</var>']:
6033 where <var>syshostname</var> is the output of <tt>hostname
6034 --fqdn</tt>.</p></sect>
6038 <heading>News system configuration</heading>
6041 All the configuration files related to the NNTP (news)
6042 servers and clients should be located under
6043 <tt>/etc/news</tt>.</p>
6046 There are some configuration issues that apply to a number
6047 of news clients and server packages on the machine. These
6051 <tag>/etc/news/organization</tag>
6052 <item><p>A string which should appear as the
6053 organization header for all messages posted
6054 by NNTP clients on the machine</p></item>
6056 <tag>/etc/news/server</tag>
6057 <item><p>Contains the FQDN of the upstream NNTP
6058 server, or localhost if the local machine is
6059 an NNTP server.</p></item>
6062 Other global files may be added as required for cross-package news
6063 configuration.</p></sect>
6067 <heading>Programs for the X Window System</heading>
6070 <em>Programs that may be configured with support for the X Window
6071 System</em> must be configured to do so and must declare any
6072 package dependencies necessary to satisfy their runtime
6073 requirements when using the X Window System, unless the package
6074 in question is of standard or higher priority, in which case
6075 X-specific binaries may be split into a separate package, or
6076 alternative versions of the package with X support may be
6082 <em>Packages which provide an X server</em> that, directly or
6083 indirectly, communicates with real input and display hardware
6084 should declare in their control data that they provide the
6085 virtual package <tt>xserver</tt>.
6088 This implements current practice, and provides an actual
6089 policy for usage of the "xserver" virtual package which
6090 appears in the virtual packages list. In a nutshell, X
6091 servers that interface directly with the display and input
6092 hardware or via another subsystem (e.g., GGI) should provide
6093 xserver. Things like Xvfb, Xnest, and Xprt should not.
6099 <em>Packages that provide a terminal emulator</em> for the X
6100 Window System which support a terminal type with a terminfo
6101 description provided in the <tt>ncurses-base</tt> package
6102 should declare in their control data that they provide the
6103 virtual package <tt>x-terminal-emulator</tt>. They should
6104 also register themselves as an alternative for
6105 <tt>/usr/bin/x-terminal-emulator</tt>, with a priority of
6110 <em>Packages that provide window managers</em> should declare in
6111 their control data that they provide the virtual package
6112 <tt>x-window-manager</tt>. They should also register themselves as an
6113 alternative for <tt>/usr/bin/x-window-manager</tt>, with a priority
6114 calculated as follows:
6116 <item>Start with a priority of 20.</item>
6117 <item>If the window manager supports the Debian menu system,
6118 add 20 points if this support is available in the
6119 package's default configuration (i.e., no
6120 configuration files belonging to the system or user
6121 have to be edited to activate the feature); if
6122 configuration files must be modified, add only 10
6124 <item>If the window manager permits the X session to be
6125 restarted using a <em>different</em> window manager
6126 (without killing the X server) in its default
6127 configuration, add 10 points; otherwise add
6133 <em>Packages that provide fonts for the X Window System</em>
6134 must do a number of things to ensure that they are both
6135 available without modification of the X or font server
6136 configuration, and that they do not corrupt files used by
6137 other font packages to register information about themselves.
6140 Fonts of any type supported by the X Window System
6141 should be be in a separate binary package from any
6142 executables, libraries, or documentation (except that
6143 specific to the fonts shipped); if a program or
6144 library is <em>unusable</em> without one or more
6145 specific fonts, the package containing the program or
6146 library should declare a dependency on the package(s)
6147 containing the font(s) it requires.
6150 BDF fonts should be converted to PCF fonts with the
6151 <tt>bdftopcf</tt> utility (available in the
6152 <tt>xutils</tt> package, <tt>gzip</tt>ped, and
6153 placed in a directory that corresponds to their
6157 100 dpi fonts should be placed in
6158 <tt>/usr/X11R6/lib/X11/fonts/100dpi/</tt>.
6161 75 dpi fonts should be placed in
6162 <tt>/usr/X11R6/lib/X11/fonts/75dpi/</tt>.
6165 Character-cell fonts, cursor fonts, and other
6166 low-resolution fonts should be placed in
6167 <tt>/usr/X11R6/lib/X11/fonts/misc/</tt>.
6172 Speedo fonts should be placed in
6173 <tt>/usr/X11R6/lib/X11/fonts/Speedo/</tt>.
6176 Type 1 fonts should be placed in
6177 <tt>/usr/X11R6/lib/X11/fonts/Type1/</tt>. If font
6178 metric files are available, they may be placed here as
6182 Subdirectories of <tt>/usr/X11R6/lib/X11/fonts/</tt>
6183 other than those listed above should be neither created nor
6184 used. (The <tt>PEX</tt> and <tt>cyrillic</tt> directories are
6185 excepted for historical reasons, but installation of files into
6186 these directories remains discouraged.)
6189 Font packages may, instead of placing files directly in
6190 the X font directories listed above, provide symbolic links in
6191 the font directory which point to the files' actual location
6192 in the filesystem. Such a location should comply with the
6196 Font packages should not contain both 75dpi and 100dpi
6197 versions of a font. If both are available, they should be
6198 provided in separate binary packages with "-75dpi" or "-100dpi"
6199 appended to the names of the packages containing the
6200 corresponding fonts.
6203 Fonts destined for the <tt>misc</tt> subdirectory should
6204 not be included in the same package as 75dpi or 100dpi fonts;
6205 instead, they should be provided in a separate package with
6206 "-misc" appended to its name.
6209 Font packages <em>must not</em> provide the files
6210 <tt>fonts.dir</tt>, <tt>fonts.alias</tt>, or
6211 <tt>fonts.scale</tt> in a font directory.
6214 <tt>fonts.dir</tt> files must not be provided at
6218 <tt>fonts.alias</tt> and <tt>fonts.scale</tt>
6219 files, if needed, should be provided in the
6221 <tt>/etc/X11/fonts/<em>fontdir</em>/<em>package</em>.<em>extension</em></tt>,
6222 where <em>fontdir</em> is the name of the
6224 <tt>/usr/X11R6/lib/X11/fonts/</tt> where the
6225 package's corresponding fonts are stored (e.g.,
6226 <tt>75dpi</tt> or <tt>misc</tt>),
6227 <em>package</em> is the name of the package that
6228 provides these fonts, and <em>extension</em> is
6229 either <tt>scale</tt> or <tt>alias</tt>,
6230 whichever corresponds to the file
6236 Font packages must declare a dependency on
6237 <tt>xutils</tt> and, in the package
6238 post-installation and post-removal scripts, invoke the
6239 <tt>mkfontdir</tt> command on each directory into
6240 which they installed fonts.
6243 Font packages that provide one or more
6244 <tt>fonts.scale</tt> files as described above must declare a
6245 versioned dependency on <tt>xutils (>=
6246 4.0.2)</tt> and invoke <tt>update-fonts-scale</tt> on each
6247 directory into which they installed fonts
6248 <em>before</em> invoking <tt>mkfontdir</tt> on that
6249 directory. This invocation must occur in both the
6250 post-installation and post-removal scripts.
6253 Font packages that provide one or more
6254 <tt>fonts.alias</tt> files as described above must
6255 declare a versioned dependency on <tt>xutils
6256 (>= 4.0.2)</tt> and, in the package
6257 post-installation and post-removal scripts, invoke
6258 <tt>update-fonts-alias</tt> on each directory into
6259 which they installed fonts.
6262 Font packages must not provide alias names for the
6263 fonts they include which collide with alias names already in
6264 use by fonts already packaged.
6267 Font packages must not provide fonts with the same XLFD
6268 registry name as another font already packaged.
6274 <em>Application defaults</em> files must be installed in the
6275 directory <tt>/etc/X11/app-defaults/</tt> (use of a
6276 localized subdirectory of <tt>/etc/X11/</tt> as described in
6277 the <em>X Toolkit Intrinsics - C Language Interface</em>
6278 manual is also permitted). They must be registered as
6279 <em>conffile</em>s or handled as configuration files. For
6280 programs that are not linked against the X Toolkit (Xt)
6281 library, customization of programs' X resources may also be
6282 supported with the provision of a file with the same name as
6283 that of the package placed in the
6284 <tt>/etc/X11/Xresources/</tt> directory, which must
6285 registered as a <em>conffile</em> or handled as a
6286 configuration file. <em>Important:</em> packages that
6287 install files into the <tt>/etc/X11/Xresources/</tt>
6288 directory <em>must</em> declare a conflict with <tt>xbase
6289 (<< 3.3.2.3a-2)</tt>; if this is not done it is
6290 possible for the installing package to destroy a
6291 previously-existing <tt>/etc/X11/Xresources</tt> file which
6292 had been customized by the system administrator.
6296 <em>Packages using the X Window System should abide by the FHS
6297 standard whenever possible</em>; they should install binaries,
6298 libraries, manual pages, and other files in FHS-mandated
6299 locations wherever possible. This means that files must
6300 not be installed into <tt>/usr/X11R6/bin/</tt>,
6301 <tt>/usr/X11R6/lib/</tt>, or <tt>/usr/X11R6/man/</tt> unless
6302 this is necessary for the package to operate properly.
6303 Configuration files for window managers and display managers
6304 should be placed in a subdirectory of <tt>/etc/X11/</tt>
6305 corresponding to the package name due to these programs'
6306 tight integration with the mechanisms of the X Window
6307 System. Application-level programs should use the
6308 <tt>/etc/</tt> directory unless otherwise mandated by
6309 policy. The installation of files into subdirectories of
6310 <tt>/usr/X11R6/include/X11/</tt> and
6311 <tt>/usr/X11R6/lib/X11/</tt> is permitted but discouraged;
6312 package maintainers should determine if subdirectories of
6313 <tt>/usr/lib/</tt> and <tt>/usr/share/</tt> can be used
6314 instead (symlinks from the X11R6 directories to
6315 FHS-compliant locations is encouraged if the program is not
6316 easily configured to look elsewhere for its files).
6317 Packages must not provide -- or install files into -- the
6318 directories <tt>/usr/bin/X11/</tt>,
6319 <tt>/usr/include/X11/</tt>, or <tt>/usr/lib/X11/</tt>.
6320 Files within a package should, however, make reference to
6321 these directories, rather than their X11R6-named
6322 counterparts <tt>/usr/X11R6/bin/</tt>,
6323 <tt>/usr/X11R6/include/X11/</tt>, and
6324 <tt>/usr/X11R6/lib/X11/</tt>, if the resources being
6325 referred to have not been moved to FHS-compliant locations.
6329 <em>Programs that require the non-DFSG-compliant OSF/Motif
6330 library</em> should be compiled against and tested with
6331 LessTif (a free re-implementation of Motif) instead. If the
6332 maintainer judges that the program or programs do not work
6333 sufficiently well with LessTif to be distributed and
6334 supported, but do so when compiled against Motif, then two
6335 versions of the package should be created; one linked
6336 statically against Motif and with <tt>-smotif</tt> appended
6337 to the package name, and one linked dynamically against
6338 Motif and with <tt>-dmotif</tt> appended to the package
6339 name. Both Motif-linked versions are dependent upon
6340 non-DFSG-compliant software and thus cannot be uploaded to
6341 the main distribution; if the software is itself
6342 DFSG-compliant it may be uploaded to the contrib
6343 distribution. While known existing versions of OSF/Motif
6344 permit unlimited redistribution of binaries linked against
6345 the library (whether statically or dynamically), it is the
6346 package maintainer's responsibility to determine whether
6347 this is permitted by the license of the copy of OSF/Motif in
6348 his or her possession.
6354 <heading>Emacs lisp programs</heading>
6357 Please refer to the `Debian Emacs Policy' (documented in
6358 <tt>debian-emacs-policy.gz</tt> of the
6359 <prgn>emacsen-common</prgn> package) for details of how to
6360 package emacs lisp programs.</p></sect>
6364 <heading>Games</heading>
6367 The permissions on /var/games are 755
6368 <tt>root.root</tt>.</p>
6371 Each game decides on its own security policy.</p>
6374 Games which require protected, privileged access to
6375 high-score files, savegames, etc., may be made
6376 set-<em>group</em>-id (mode 2755) and owned by
6377 <tt>root.games</tt>, and use files and directories with
6378 appropriate permissions (770 <tt>root.games</tt>, for
6379 example). They must not be made
6380 set-<em>user</em>-id, as this causes security problems. (If
6381 an attacker can subvert any set-user-id game they can
6382 overwrite the executable of any other, causing other players
6383 of these games to run a Trojan horse program. With a
6384 set-group-id game the attacker only gets access to less
6385 important game data, and if they can get at the other
6386 players' accounts at all it will take considerably more
6390 Some packages, for example some fortune cookie programs, are
6391 configured by the upstream authors to install with their
6392 data files or other static information made unreadable so
6393 that they can only be accessed through set-id programs
6394 provided. You should not do this in a Debian package: anyone can
6395 download the <tt>.deb</tt> file and read the data from it,
6396 so there is no point making the files unreadable. Not
6397 making the files unreadable also means that you don't have
6398 to make so many programs set-id, which reduces the risk of a
6402 As described in the FHS, binaries of games should be
6403 installed in the directory <tt>/usr/games</tt>. This also
6404 applies to games that use the X Window System. Manual pages
6405 for games (X and non-X games) should be installed in
6406 <tt>/usr/share/man/man6</tt>.</p>
6410 <chapt><heading>Documentation</heading>
6414 <heading>Manual pages</heading>
6417 You should install manual pages in <prgn>nroff</prgn> source
6418 form, in appropriate places under <tt>/usr/share/man</tt>. You
6419 should only use sections 1 to 9 (see the FHS for more
6420 details). You must not install a preformatted `cat
6424 Each program, utility, and function should have an
6425 associated manpage included in the same package. It is
6426 suggested that all configuration files also have a manual
6427 page included as well.
6431 If no manual page is available for a particular program,
6432 utility, function or configuration file and this is reported as a bug on
6433 debian-bugs, a symbolic link from the requested manual page
6434 to the <manref name="undocumented" section="7"> manual page
6435 may be provided. This symbolic link can be created from
6436 <tt>debian/rules</tt> like this:
6438 ln -s ../man7/undocumented.7.gz \
6439 debian/tmp/usr/share/man/man[1-9]/the_requested_manpage.[1-9].gz
6441 This manpage claims that the lack of a manpage has been
6442 reported as a bug, so you may only do this if it really has
6443 (you can report it yourself, if you like). Do not close the
6444 bug report until a proper manpage is available.</p>
6447 You may forward a complaint about a missing manpage to the
6448 upstream authors, and mark the bug as forwarded in the
6449 Debian bug tracking system. Even though the GNU Project do
6450 not in general consider the lack of a manpage to be a bug,
6451 we do--if they tell you that they don't consider it a bug
6452 you should leave the bug in our bug tracking system open
6456 Manual pages should be installed compressed using <tt>gzip
6460 If one manpage needs to be accessible via several names it
6461 is better to use a symbolic link than the <tt>.so</tt>
6462 feature, but there is no need to fiddle with the relevant
6463 parts of the upstream source to change from <tt>.so</tt> to
6464 symlinks--don't do it unless it's easy. You should not create hard
6465 links in the manual page directories, nor put
6466 absolute filenames in <tt>.so</tt> directives. The filename
6467 in a <tt>.so</tt> in a manpage should be relative to the
6468 base of the manpage tree (usually
6469 <tt>/usr/share/man</tt>).</p></sect>
6473 <heading>Info documents</heading>
6476 Info documents should be installed in <tt>/usr/share/info</tt>.
6477 They should be compressed with <tt>gzip -9</tt>.</p>
6480 Your package should call <prgn>install-info</prgn> to update the Info
6482 file, in its post-installation script:
6484 install-info --quiet --section Development Development \
6485 /usr/share/info/foobar.info
6489 It is a good idea to specify a section for the location of
6490 your program; this is done with the <tt>--section</tt>
6491 switch. To determine which section to use, you should look
6492 at <tt>/usr/share/info/dir</tt> on your system and choose the most
6493 relevant (or create a new section if none of the current
6494 sections are relevant). Note that the <tt>--section</tt>
6495 flag takes two arguments; the first is a regular expression
6496 to match (case-insensitively) against an existing section,
6497 the second is used when creating a new one.</p>
6500 You should remove the entries in the pre-removal script:
6502 install-info --quiet --remove /usr/share/info/foobar.info
6506 If <prgn>install-info</prgn> cannot find a description entry
6507 in the Info file you must supply one. See <manref
6508 name="install-info" section="8"> for details.</p>
6512 <heading>Additional documentation</heading>
6515 Any additional documentation that comes with the package may
6516 be installed at the discretion of the package maintainer.
6517 Text documentation should be installed in a directory
6518 <tt>/usr/share/doc/<var>package</var></tt>, where
6519 <var>package</var> is the name of the package, and
6520 compressed with <tt>gzip -9</tt> unless it is small.</p>
6523 If a package comes with large amounts of documentation which
6524 many users of the package will not require you should create
6525 a separate binary package to contain it, so that it does not
6526 take up disk space on the machines of users who do not need
6527 or want it installed.</p>
6530 It is often a good idea to put text information files
6531 (<tt>README</tt>s, changelogs, and so forth) that come with
6532 the source package in <tt>/usr/share/doc/<var>package</var></tt>
6533 in the binary package. However, you don't need to install
6534 the instructions for building and installing the package, of
6538 Files in <tt>/usr/share/doc</tt> should not be referenced by
6539 any program, and the system administrator should be able to
6540 delete them without causing any programs to break. Any files
6541 that are referenced by programs but are also useful as
6542 standalone documentation should be installed under
6543 <tt>/usr/share/<package>/</tt> and symlinked in
6544 <tt>/usr/share/doc/<package>/</tt>.
6550 <heading>Accessing the documentation</heading>
6553 Former Debian releases placed all additional documentation
6554 in <tt>/usr/doc/<var>package</var></tt>. To realize a
6556 <tt>/usr/share/doc/<var>package</var></tt>, each package
6557 must maintain a symlink <tt>/usr/doc/<var>package</var></tt>
6558 that points to the new location of its documentation in
6559 <tt>/usr/share/doc/<var>package</var></tt><footnote>These
6560 symlinks will be removed in the future, but they have to be
6561 there for compatibility reasons until all packages have
6562 moved and the policy is changed accordingly.</footnote>.
6563 The symlink must be created when the package is installed;
6564 it cannot be contained in the package itself due to problems
6565 with <prgn>dpkg</prgn>. One reasonable way to accomplish
6566 this is to put the following in the package's
6567 <prgn>postinst</prgn>:
6569 if [ "$1" = "configure" ]; then
6570 if [ -d /usr/doc -a ! -e /usr/doc/#PACKAGE# \
6571 -a -d /usr/share/doc/#PACKAGE# ]; then
6572 ln -sf ../share/doc/#PACKAGE# /usr/doc/#PACKAGE#
6576 And the following in the package's <prgn>prerm</prgn>:
6578 if [ \( "$1" = "upgrade" -o "$1" = "remove" \) \
6579 -a -L /usr/doc/#PACKAGE# ]; then
6580 rm -f /usr/doc/#PACKAGE#
6587 <heading>Preferred documentation formats</heading>
6590 The unification of Debian documentation is being carried out
6594 If your package comes with extensive documentation in a
6595 mark up format that can be converted to various other formats
6596 you should if possible ship HTML versions in a binary
6597 package, in the directory
6598 <tt>/usr/share/doc/<var>appropriate package</var></tt> or its
6601 <p>The rationale: The important thing here is that HTML
6602 docs should be available in <em>some</em> package, not
6603 necessarily in the main binary package, though. </p>
6608 Other formats such as PostScript may be provided at your
6612 <sect id="copyrightfile">
6613 <heading>Copyright information</heading>
6616 Every package must be accompanied by a verbatim copy of its
6617 copyright and distribution license in the file
6618 /usr/share/doc/<package-name>/copyright. This file must
6619 neither be compressed nor be a symbolic link.</p>
6622 In addition, the copyright file must say where the upstream
6623 sources (if any) were obtained, and should explain briefly what
6624 modifications were made in the Debian version of the package
6625 compared to the upstream one. It should name the original
6626 authors of the package and the Debian maintainer(s) who were
6627 involved with its creation.</p>
6630 A copy of the file which will be installed in
6631 <tt>/usr/share/doc/<var>package</var>/copyright</tt> should be
6632 in <tt>debian/copyright</tt>.</p>
6636 /usr/share/doc/<package-name> may be a symbolic link to a
6637 directory in /usr/share/doc only if two packages both come from
6638 the same source and the first package has a "Depends"
6639 relationship on the second. These rules are important
6640 because copyrights must be extractable by mechanical
6644 Packages distributed under the UCB BSD license, the Artistic
6645 license, the GNU GPL, and the GNU LGPL should refer to the
6646 files /usr/share/common-licenses/BSD,
6647 /usr/share/common-licenses/Artistic,
6648 /usr/share/common-licenses/GPL, and
6649 /usr/share/common-licenses/LGPL.
6652 Why "licenses" and not "copyright"? Because
6653 <tt>/usr/doc/copyright</tt> used to contain all the
6654 copyright files, plus the four common licenses GPL,
6655 LGPL, Artistic and BSD. Now individual copyright files
6656 for packages are no longer in a common directory. Once
6657 <tt>/usr/doc/copyright</tt> is almost empty it makes
6658 sense to rename "copyright" to "licenses"
6661 Why "common-licenses" and not "licenses"? Because if I
6662 put just "licenses" I'm sure I will receive a bug report
6663 saying "license foo is not included in the licenses
6664 directory. They are not all the licenses, just a few
6665 common ones. I could use /usr/share/doc/common-licenses
6666 but I think this is too long, and, after all, the GPL
6667 does not "document" anything, it is merely a license.
6673 You should not use the copyright file as a general <tt>README</tt>
6674 file. If your package has such a file it should be
6675 installed in <tt>/usr/share/doc/<var>package</var>/README</tt> or
6676 <tt>README.Debian</tt> or some other appropriate place.</p>
6680 <heading>Examples</heading>
6683 Any examples (configurations, source files, whatever),
6684 should be installed in a directory
6685 <tt>/usr/share/doc/<var>package</var>/examples</tt>. These
6686 files should not be referenced by any program--they're there
6687 for the benefit of the system administrator and users, as
6688 documentation only. Architecture-specific example files
6689 should be installed in a directory
6690 <tt>/usr/lib/<var>package</var>/examples</tt>, and files in
6691 <tt>/usr/share/doc/<var>package</var>/examples</tt> symlink
6692 to files in it. Or the latter directory may be a symlink to
6696 <sect id="instchangelog">
6697 <heading>Changelog files</heading>
6700 Packages that are not Debian-native must contain a copy of
6701 <tt>debian/changelog</tt> file from the Debian source tree
6702 in <tt>/usr/share/doc/<var>package</var></tt> as
6703 <tt>changelog.Debian.gz</tt>. If an upstream changelog is
6704 available, it should be accessible as
6705 <tt>/usr/share/doc/<var>package</var>/changelog.gz</tt> in
6706 plain text. If the upstream changelog is distributed in
6707 HTML, it should be made available in that form as
6708 <tt>/usr/share/doc/<var>package</var>/changelog.html.gz</tt>
6709 and the <tt>changelog.gz</tt> should be generated using, eg,
6710 <tt>lynx -dump -nolist</tt>. If the upstream changelog files
6711 do not already conform to this naming convention, then this
6712 may be achieved either by renaming the files, or adding a
6713 symbolic link, at the maintainer's discretion.
6716 Rationale: People should not have to look into two
6717 places for upstream changelogs merely because they are
6725 All these files should be installed compressed using <tt>gzip -9</tt>,
6726 as they will become large with time even if they start out
6731 If the package has only one changelog which is used both as
6732 the Debian changelog and the upstream one because there is
6733 no separate upstream maintainer then that changelog should
6734 usually be installed as
6735 <tt>/usr/share/doc/<var>package</var>/changelog.gz</tt>; if
6736 there is a separate upstream maintainer, but no upstream
6737 changelog, then the Debian changelog should still be called
6738 <tt>changelog.Debian.gz</tt>.</p>