Chapter 6. Best Packaging PracticesChapter 6. Best Packaging PracticesTable of Contents
Debian's quality is largely due to the , which
defines explicit baseline requirements which all Debian packages must fulfill.
Yet there is also a shared history of experience which goes beyond the Debian
Policy, an accumulation of years of experience in packaging.
talented people have created great tools, tools which help you, the Debian
maintainer, create and maintain excellent packages.
This chapter provides some best practices for Debian developers.
recommendations are merely that, and are not requirements or policy.
just some subjective hints, advice and pointers collected from Debian
developers.
Feel free to pick and choose whatever works best for you.
6.1. Best practices for debian/rules
The following recommendations apply to the debian/rules
Since debian/rules controls the build process and
selects the files which go into the package (directly or indirectly), it's
usually the file maintainers spend the most time on.
6.1.1. Helper scripts
The rationale for using helper scripts in debian/rules is
that they let maintainers use and share common logic among many packages.
for instance the question of installing menu entries: you need to put the file
into /usr/share/menu (or /usr/lib/menu
for executable binary menufiles, if this is needed), and add commands to the
maintainer scripts to register and unregister the menu entries.
Since this is
a very common thing for packages to do, why should each maintainer rewrite all
this on their own, sometimes with bugs?
Also, supposing the menu directory
changed, every package would have to be changed.
Helper scripts take care of these issues.
Assuming you comply with the
conventions expected by the helper script, the helper takes care of all the
Changes in policy can be made
then packages
just need to be rebuilt with the new version of the helper and no other
contains a couple of different helpers.
common and best (in our opinion) helper system is debhelper.
Previous helper systems, such as
debmake, were monolithic: you couldn't
pick and choose which part of the helper you found useful, but had to use the
helper to do everything.
debhelper,
however, is a number of separate little dh_* programs.
instance, dh_installman installs and compresses man pages,
dh_installmenu installs menu files, and so on.
offers enough flexibility to be able to use the little helper scripts, where
useful, in conjunction with hand-crafted commands in
debian/rules.
You can get started with debhelper by
reading debhelper(1), and looking at the examples that come
with the package.
dh_make, from the dh-make package (see ),
can be used to convert a vanilla source package to a debhelperized package.
This shortcut, though,
should not convince you that you do not need to bother understanding the
individual dh_* helpers.
If you are going to use a helper,
you do need to take the time to learn to use that helper, to learn its
expectations and behavior.
6.1.2. Separating your patches into multiple files
Big, complex packages may have many bugs that you need to deal with.
correct a number of bugs directly in the source, and you're not careful, it can
get hard to differentiate the various patches that you applied.
It can get
quite messy when you have to update the package to a new upstream version which
integrates some of the fixes (but not all).
You can't take the total set of
diffs (e.g., from .diff.gz) and work out which patch sets
to back out as a unit as bugs are fixed upstream.
Fortunately, with the source format “3.0 (quilt)” it is now possible to
keep patches separate without having to modify debian/rules
to setup a patch system. Patches are stored in debian/patches/
and when the source package is unpacked patches listed in
debian/patches/series are automatically applied.
As the name implies, patches can be managed with quilt.
When using the older source “1.0”, it's also possible to separate patches
but a dedicated patch system must be used: the patch files are shipped
within the Debian patch file (.diff.gz), usually
within the debian/ directory. The only difference is
that they aren't applied immediately by dpkg-source,
but by the build rule of
debian/rules, through a dependency on the
patch rule.
Conversely, they are reverted in the
clean rule, through a dependency on the
unpatch rule.
quilt is the recommended tool for this.
It does all of the above, and also allows to manage patch series.
quilt package for more information.
There are other tools to manage patches, like dpatch,
and the patch system integrated with
6.1.3. Multiple binary packages
A single source package will often build several binary packages, either to
provide several flavors of the same software (e.g., the vim source package) or to make several small
packages instead of a big one (e.g., so the user can install only the subset
needed, and thus save some disk space).
The second case can be easily managed in debian/rules.
You just need to move the appropriate files from the build directory into the
package's temporary trees.
You can do this using install or
dh_install from debhelper.
Be sure to check the different
permutations of the various packages, ensuring that you have the inter-package
dependencies set right in debian/control.
The first case is a bit more difficult since it involves multiple recompiles of
the same software but with different configuration options.
The vim source package is an example of how to manage
this using an hand-crafted debian/rules file.
6.2. Best practices for debian/control
The following practices are relevant to the debian/control
They supplement the .
The description of the package, as defined by the corresponding field in the
control file, contains both the package synopsis and the
long description for the package.
common guidelines for both parts of the package description.
Following that,
provides guidelines specific to the
synopsis, and
contains guidelines specific to
the description.
6.2.1. General guidelines for package descriptions
The package description should be written for the average likely user, the
average person who will use and benefit from the package.
For instance,
development packages are for developers, and can be technical in their
More general-purpose applications, such as editors, should be
written for a less technical user.
Our review of package descriptions lead us to conclude that most package
descriptions are technical, that is, are not written to make sense for
non-technical users.
Unless your package really is only for technical users,
this is a problem.
How do you write for non-technical users?
Avoid jargon.
Avoid referring to
other applications or frameworks that the user might not be familiar with —
GNOME or KDE is fine, since users are probably familiar with these terms, but
GTK+ is probably not.
Try not to assume any knowledge at all.
If you must use
technical terms, introduce them.
Be objective.
Package descriptions are not the place for advocating your
package, no matter how much you love it.
Remember that the reader may not care
about the same things you care about.
References to the names of any other software packages, protocol names,
standards, or specifications should use their canonical forms, if one exists.
For example, use X Window System, X11, or X; not X Windows, X-Windows, or X
Use GTK+, not GTK or gtk.
Use GNOME, not Gnome.
Use PostScript, not
Postscript or postscript.
If you are having problems writing your description, you may wish to send it
along to && and request feedback.
6.2.2. The package synopsis, or short description
Policy says the synopsis line (the short description) must be concise, not
repeating the package name, but also informative.
The synopsis functions as a phrase describing the package, not a complete
sentence, so sentential punctuation is inappropriate: it does not need extra
capital letters or a final period (full stop). It should also omit any initial
indefinite or definite article — "a", "an", or "the". Thus for instance:
Package: libeg0
Description: exemplification support library
Technically this is a noun phrase minus articles, as opposed to a verb phrase.
A good heuristic is that it should be possible to substitute the package
name and synopsis into this formula:
The package name provides {a,an,the,some}
Sets of related packages may use an alternative scheme that divides the
synopsis into two parts, the first a description of the whole suite and the
second a summary of the package's role within it:
Package: eg-tools
Description: simple exemplification system (utilities)
Package: eg-doc
Description: simple exemplification system - documentation
These synopses follow a modified formula. Where a package
"name" has a synopsis
"suite (role)" or
"suite - role", the
elements should be phrased so that they fit into the formula:
The package name provides {a,an,the}
role for the suite.
6.2.3. The long description
The long description is the primary information available to the user about a
package before they install it.
It should provide all the information needed
to let the user decide whether to install the package.
Assume that the user
has already read the package synopsis.
The long description should consist of full and complete sentences.
The first paragraph of the long description should answer the following
questions: what does the package do?
what task does it help the user
accomplish?
It is important to describe this in a non-technical way, unless of
course the audience for the package is necessarily technical.
The following paragraphs should answer the following questions: Why do I as a
user need this package?
What other features does the package have?
outstanding features and deficiencies are there compared to other packages
(e.g., if you need X, use Y instead)?
Is this package related to other
packages in some way that is not handled by the package manager (e.g., this is
the client for the foo server)?
Be careful to avoid spelling and grammar mistakes.
Ensure that you spell-check
Both ispell and aspell have special
modes for checking debian/control files:
ispell -d american -g debian/control
aspell -d en -D -c debian/control
Users usually expect these questions to be answered in the package description:
What does the package do?
If it is an add-on to another package, then the
short description of the package we are an add-on to should be put in here.
Why should I want this package?
This is related to the above, but not the same
this is cool, fast, interfaces with PGP and LDAP
and IMAP, has features X, Y, and Z).
If this package should not be installed directly, but is pulled in by another
package, this should be mentioned.
If the package is experimental, or there are other reasons
it should not be used, if there are other packages that should be used instead,
it should be here as well.
How is this package different from the competition?
Is it a better
implementation?
more features?
different features?
Why should I choose this
6.2.4. Upstream home page
We recommend that you add the URL for the package's home page in the
Homepage field of the Source section
in debian/control.
Adding this information in the
package description itself is considered deprecated.
6.2.5. Version Control System location
There are additional fields for the location of the Version Control System in
debian/control.
6.2.5.1. Vcs-Browser
Value of this field should be a http:// URL pointing to a
web-browsable copy of the Version Control System repository used to maintain
the given package, if available.
The information is meant to be useful for the final user, willing to browse the
latest work done on the package (e.g.
when looking for the patch fixing a bug
tagged as pending in the bug tracking system).
6.2.5.2. Vcs-*
Value of this field should be a string identifying unequivocally the location
of the Version Control System repository used to maintain the given package, if
available.
* identify the Version Control S currently
the following systems are supported by the package tracking system:
arch, bzr (Bazaar),
cvs, darcs, git,
hg (Mercurial), mtn (Monotone),
svn (Subversion).
It is allowed to specify different VCS
fields for the same package: they will all be shown in the PTS web interface.
The information is meant to be useful for a user knowledgeable in the given
Version Control System and willing to build the current version of a package
from the VCS sources.
Other uses of this information might include automatic
building of the latest VCS version of the given package.
To this end the
location pointed to by the field should better be version agnostic and point to
the main branch (for VCSs supporting such a concept).
Also, the location
pointed to should be accessib fulfilling this requirement
might imply pointing to an anonymous access of the repository instead of
pointing to an SSH-accessible version of the same.
In the following example, an instance of the field for a Subversion repository
of the vim package is shown.
the URL is in the svn:// scheme (instead of
svn+ssh://) and how it points to the
trunk/ branch.
The use of the
Vcs-Browser and Homepage fields
described above is also shown.
Source: vim
Section: editors
Priority: optional
Vcs-Svn: svn://svn.debian.org/svn/pkg-vim/trunk/packages/vim
Vcs-Browser: https://svn.debian.org/wsvn/pkg-vim/trunk/packages/vim
Homepage: http://www.vim.org
6.3. Best practices for debian/changelog
The following practices supplement the .
6.3.1. Writing useful changelog entries
The changelog entry for a package revision documents changes in that revision,
and only them.
Concentrate on describing significant and user-visible changes
that were made since the last version.
Focus on what was changed — who, how and when are
usually less important.
Having said that, remember to politely attribute
people who have provided notable help in making the package (e.g., those who
have sent in patches).
There's no need to elaborate the trivial and obvious changes.
You can also
aggregate several changes in one entry.
On the other hand, don't be overly
terse if you have undertaken a major change.
Be especially clear if there are
changes that affect the behaviour of the program.
For further explanations,
use the README.Debian file.
Use common English so that the majority of readers can comprehend it.
abbreviations, tech-speak and jargon when explaining changes that close bugs,
especially for bugs filed by users that did not strike you as particularly
technically savvy.
Be polite, don't swear.
It is sometimes desirable to prefix changelog entries with the names of the
files that were changed.
However, there's no need to explicitly list each and
every last one of the changed files, especially if the change was small or
repetitive.
You may use wildcards.
When referring to bugs, don't assume anything.
Say what the problem was, how
it was fixed, and append the closes: #nnnnn string.
for more information.
6.3.2. Common misconceptions about changelog entries
The changelog entries should not document
generic packaging issues (Hey, if you're looking for foo.conf, it's in
/etc/blah/.), since administrators and users are supposed to be at least
remotely acquainted with how such things are generally arranged on Debian
Do, however, mention if you change the location of a configuration
The only bugs closed with a changelog entry should be those that are actually
fixed in the same package revision.
Closing unrelated bugs in the changelog is
bad practice.
The changelog entries should not be used for
random discussion with bug reporters (I don't see segfaults when starting foo
send in more info), general statements on life, the universe
and everything (sorry this upload took me so long, but I caught the flu), or
pleas for help (the bug list on this package is huge, please lend me a hand).
Such things usually won't be noticed by their target audience, but may annoy
people who wish to read information about actual changes in the package.
for more information on how to use the bug
tracking system.
It is an old tradition to acknowledge bugs fixed in non-maintainer uploads in
the first changelog entry of the proper maintainer upload.
As we have version
tracking now, it is enough to keep the NMUed changelog entries and just mention
this fact in your own changelog entry.
6.3.3. Common errors in changelog entries
The following examples demonstrate some common errors or examples of bad style
in changelog entries.
* Fixed all outstanding bugs.
This doesn't tell readers anything too useful, obviously.
* Applied patch from Jane Random.
What was the patch about?
* Late night install target overhaul.
Overhaul which accomplished what?
Is the mention of late night supposed to
remind us that we shouldn't trust that code?
* Fix vsync FU w/ ancient CRTs.
Too many acronyms, and it's not overly clear what the, uh, fsckup (oops, a
curse word!) was actually about, or how it was fixed.
* This is not a bug, closes: #nnnnnn.
First of all, there's absolutely no need to upload the package to convey this
instead, use the bug tracking system.
Secondly, there's no
explanation as to why the report is not a bug.
* Has been fixed for ages, but I closes: #54321.
If for some reason you didn't mention the bug number in a previous changelog
entry, there's no problem, just close the bug normally in the BTS.
There's no
need to touch the changelog file, presuming the description of the fix is
already in (this applies to the fixes by the upstream authors/maintainers as
well, you don't have to track bugs that they fixed ages ago in your changelog).
* Closes: #12345, #12346, #15432
Where's the description?
If you can't think of a descriptive message, start by
inserting the title of each different bug.
6.3.4. Supplementing changelogs with NEWS.Debian files
Important news about changes in a package can also be put in
NEWS.Debian files.
The news will be displayed by tools like apt-listchanges, before all the rest
of the changelogs.
This is the preferred means to let the user know about
significant changes in a package.
It is better than using debconf notes since
it is less annoying and the user can go back and refer to the
NEWS.Debian file after the install.
And it's better than listing
major changes in README.Debian, since the user can easily
miss such notes.
The file format is the same as a debian changelog file, but leave off the
asterisks and describe each news item with a full paragraph when necessary
rather than the more concise summaries that would go in a changelog.
good idea to run your file through dpkg-parsechangelog to
check its formatting as it will not be automatically checked during build as
the changelog is.
Here is an example of a real
NEWS.Debian file:
cron (3.0pl1-74) urgency=low
The checksecurity script is no longer included with the cron package:
it now has its own package, checksecurity. If you liked the
functionality provided with that script, please install the new
-- Steve Greenland &stevegr@debian.org&
6 Sep :03 -0500
The NEWS.Debian file is installed as
/usr/share/doc/package/NEWS.Debian.gz.
It is compressed, and always has that name even in Debian native packages.
If you use debhelper, dh_installchangelogs
will install debian/NEWS files for you.
Unlike changelog files, you need not update NEWS.Debian
files with every release.
Only update them if you have something particularly
newsworthy that user should know about.
If you have no news at all, there's no
need to ship a NEWS.Debian file in your package.
is good news!
6.4. Best practices for maintainer scripts
Maintainer scripts include the files debian/postinst,
debian/preinst, debian/prerm and
debian/postrm.
These scripts take care of any package
installation or deinstallation setup which isn't handled merely by the creation
or removal of files and directories.
The following instructions supplement the
Maintainer scripts must be idempotent.
That means that you need to make sure
nothing bad will happen if the script is called twice where it would usually be
called once.
Standard input and output may be redirected (e.g.
into pipes) for logging
purposes, so don't rely on them being a tty.
All prompting or interactive configuration should be kept to a minimum.
it is necessary, you should use the debconf package for the interface.
Remember that
prompting in any case can only be in the configure stage of
the postinst script.
Keep the maintainer scripts as simple as possible.
We suggest you use pure
POSIX shell scripts.
Remember, if you do need any bash features, the
maintainer script must have a bash shebang line.
POSIX shell or Bash are
preferred to Perl, since they enable debhelper to easily add bits to the scripts.
If you change your maintainer scripts, be sure to test package removal, double
installation, and purging.
Be sure that a purged package is completely gone,
that is, it must remove any files created, directly or indirectly, in any
maintainer script.
If you need to check for the existence of a command, you should use something
if [ -x /usr/sbin/install-docs ]; then ...
If you don't wish to hard-code the path of a command in your maintainer script,
the following POSIX-compliant shell function may help:
pathfind() {
OLDIFS="$IFS"
for p in $PATH; do
if [ -x "$p/$*" ]; then
IFS="$OLDIFS"
IFS="$OLDIFS"
You can use this function to search $PATH for a command
name, passed as an argument.
It returns true (zero) if the command was found,
and false if not.
This is really the most portable way, since command
-v, type, and which are not
While which is an acceptable alternative, since it is from
the required debianutils package, it's
not on the root partition.
That is, it's in /usr/bin
rather than /bin, so one can't use it in scripts which are
run before the /usr partition is mounted.
Most scripts
won't have this problem, though.
6.5. Configuration management with debconf
Debconf is a configuration management
system which can be used by all the various packaging scripts
(postinst mainly) to request feedback from the user
concerning how to configure the package.
Direct user interactions must now be
avoided in favor of debconf
interaction.
This will enable non-interactive installations in the future.
Debconf is a great tool but it is often poorly used.
Many common mistakes are
listed in the debconf-devel(7) man page.
It is something that you
must read if you decide to use debconf.
Also, we document some best practices
These guidelines include some writing style and typography recommendations,
general considerations about debconf usage as well as more specific
recommendations for some parts of the distribution (the installation system for
instance).
6.5.1. Do not abuse debconf
Since debconf appeared in Debian, it has been widely abused and several
criticisms received by the Debian distribution come from debconf abuse with the
need of answering a wide bunch of questions before getting any little thing
installed.
Keep usage notes to what they belong: the NEWS.Debian, or README.Debian file.
Only use notes for important notes which may directly affect the package
usability.
Remember that notes will always block the install until confirmed
or bother the user by email.
Carefully choose the questions priorities in maintainer scripts.
debconf-devel(7) for details about priorities.
questions should use medium and low priorities.
6.5.2. General recommendations for authors and translators6.5.2.1. Write correct English
Most Debian package maintainers are not native English speakers.
So, writing
properly phrased templates may not be easy for them.
Please use (and abuse) && mailing
Have your templates proofread.
Badly written templates give a poor image of your package, of your work... or
even of Debian itself.
Avoid technical jargon as much as possible.
If some terms sound common to you,
they may be impossible to understand for others.
If you cannot avoid them, try
to explain them (use the extended description).
When doing so, try to balance
between verbosity and simplicity.
6.5.2.2. Be kind to translators
Debconf templates may be translated.
Debconf, along with its sister package
po-debconf offers a simple framework for getting templates
translated by translation teams or even individuals.
Please use gettext-based templates.
Install po-debconf on your development system and read its
documentation (man po-debconf is a good start).
Avoid changing templates too often.
Changing templates text induces more work
to translators which will get their translation fuzzied.
A fuzzy translation is
a string for which the original changed since it was translated, therefore
requiring some update by a translator to be usable.
When changes are small
enough, the original translation is kept in PO files but marked as
If you plan to do changes
to your original templates, please use the notification system provided with
the po-debconf package, namely the
podebconf-report-po, to contact translators.
Most active
translators are very responsive and getting their work included along with your
modified templates will save you additional uploads.
If you use gettext-based
templates, the translator's name and e-mail addresses are mentioned in the PO
files headers and will be used by
podebconf-report-po.
A recommended use of that utility is:
cd debian/po && podebconf-report-po --call --languageteam --withtranslators --deadline="+10 days"
This command will first synchronize the PO and POT files in debian/po with
the templates files listed in debian/po/POTFILES.in.
Then, it will send a call for new translations, in the && mailing
list. Finally, it will also send a call for translation updates to the language team
(mentioned in the Language-Team field of each PO file)
as well as the last translator (mentioned in
Last-translator).
Giving a deadline to translators is always appreciated, so that they can
organize their work. Please remember that some translation teams have a
formalized translate/review process and a delay lower than 10 days is
considered as unreasonable. A shorter delay puts too much pressure on translation
teams and should be kept for very minor changes.
If in doubt, you may also contact the translation team for a given language
(debian-l10n-xxxxx@lists.debian.org), or the
&& mailing list.
6.5.2.3. Unfuzzy complete translations when correcting typos and spelling
When the text of a debconf template is corrected and you are sure that the change does not affect translations, please be kind to translators
and unfuzzy their translations.
If you don't do so, the whole template will not be translated as long as a
translator will send you an update.
To unfuzzy translations, you can use
msguntypot (part of the po4a package).
Regenerate the POT and PO files.
debconf-updatepo
Make a copy of the POT file.
cp templates.pot templates.pot.orig
Make a copy of all the PO files.
mkdir po_ cp *.po po_fridge
Change the debconf template files to fix the typos.
Regenerate the POT and PO files (again).
debconf-updatepo
At this point, the typo fix fuzzied all the translations, and this
unfortunate change is the only one between the PO files of your main
directory and the one from the fridge. Here is how to solve this.
Discard fuzzy translation, restore the ones from the fridge.
cp po_fridge/*.po .
Manually merge the PO files with the new POT file, but taking the useless fuzzy into account.
msguntypot -o templates.pot.orig -n templates.pot *.po
rm -rf templates.pot.orig po_fridge6.5.2.4. Do not make assumptions about interfaces
Templates text should not make reference to widgets belonging to some debconf
interfaces.
Sentences like If you answer Yes... have no meaning for users of
graphical interfaces which use checkboxes for boolean questions.
String templates should also avoid mentioning the default values in their
description.
First, because this is redundant with the values seen by the
Also, because these default values may be different from the maintainer
choices (for instance, when the debconf database was preseeded).
More generally speaking, try to avoid referring to user actions.
6.5.2.5. Do not use first person
You should avoid the use of first person (I will do this... or We
recommend...).
The computer is not a person and the Debconf templates do not
speak for the Debian developers.
You should use neutral construction.
of you who already wrote scientific publications, just write your templates
like you would write a scientific paper.
However, try using active voice if
still possible, like Enable this if ... instead of This can be enabled if....
6.5.2.6. Be gender neutral
The world is made of men and women.
Please use gender-neutral constructions in
your writing.
6.5.3. Templates fields definition
This part gives some information which is mostly taken from the debconf-devel(7) manual page.
6.5.3.1. Type6.5.3.1.1. string
Results in a free-form input field that the user can type any string into.
6.5.3.1.2. password
Prompts the user for a password.
U be aware that the
password the user enters will be written to debconf's database.
You should
probably clean that value out of the database as soon as is possible.
6.5.3.1.3. boolean
A true/false choice.
Remember: true/false, not
6.5.3.1.4. select
A choice between one of a number of values.
The choices must be specified in a
field named 'Choices'.
Separate the possible values with commas and spaces,
like this: Choices: yes, no, maybe.
If choices are translatable strings, the 'Choices' field may be marked as
translatable by using __Choices. The double underscore will split out
each choice in a separate string.
The po-debconf system also offers interesting possibilities
to only mark some choices as translatable.
Template: foo/bar
Type: Select
#flag:translate:3
__Choices: PAL, SECAM, Other
_Description: TV standard:
Please choose the TV standard used in your country.
In that example, only the 'Other' string is translatable while others
are acronyms that should not be translated. The above allows only
'Other' to be included in PO and POT files.
The debconf templates flag system offers many such possibilities. The
po-debconf(7) manual page lists all these possibilities.
6.5.3.1.5. multiselect
Like the select data type, except the user can choose any number of items from
the choices list (or chose none of them).
6.5.3.1.6. note
Rather than being a question per se, this datatype indicates a note that can be
displayed to the user.
It should be used only for important notes that the
user really should see, since debconf will go to great pains to make sure the
halting the install for them to press a key, and even mailing the
note to them in some cases.
6.5.3.1.7. text
This type is now considered obsolete: don't use it.
6.5.3.1.8. error
This type is designed to handle error messages.
It is mostly similar to the
note type.
Frontends may present it differently (for instance, the dialog
frontend of cdebconf draws a red screen instead of the usual blue one).
It is recommended to use this type for any message that needs user attention
for a correction of any kind.
6.5.3.2. Description: short and extended description
Template descriptions have two parts: short and extended.
description is in the Description: line of the template.
The short description should be kept short (50 characters or so) so that it may
be accommodated by most debconf interfaces.
Keeping it short also helps
translators, as usually translations tend to end up being longer than the
The short description should be able to stand on its own.
Some interfaces do
not show the long description by default, or only if the user explicitely asks
for it or even do not show it at all.
Avoid things like What do you want to
The short description does not necessarily have to be a full sentence.
part of the keep it short and efficient recommendation.
The extended description should not repeat the short description word for word.
If you can't think up a long description, then first, think some more.
debian-devel.
Ask for help.
Take a writing class!
That extended description
is important.
If after all that you still can't come up with anything, leave
The extended description should use complete sentences.
Paragraphs should be
kept short for improved readability.
Do not mix two ideas in the same
paragraph but rather use another paragraph.
Don't be too verbose.
User tend to ignore too long screens.
20 lines are by
experience a border you shouldn't cross, because that means that in the
classical dialog interface, people will need to scroll, and lot of people just
don't do that.
The extended description should never
include a question.
For specific rules depending on templates type (string, boolean, etc.), please
read below.
6.5.3.3. Choices
This field should be used for select and multiselect types.
It contains the
possible choices which will be presented to users.
These choices should be
separated by commas.
6.5.3.4. Default
This field is optional.
It contains the default answer for string, select and
multiselect templates.
For multiselect templates, it may contain a
comma-separated list of choices.
6.5.4. Templates fields specific style guide6.5.4.1. Type field
No specific indication except: use the appropriate type by referring to the
previous section.
6.5.4.2. Description field
Below are specific instructions for properly writing the Description (short and
extended) depending on the template type.
6.5.4.2.1. String/password templates
The short description is a prompt and not a
Avoid question style prompts (IP Address?) in favour of opened prompts
(IP address:).
The use of colons is recommended.
The extended description is a complement to the short description.
extended part, explain what is being asked, rather than ask the same question
again using longer words.
Use complete sentences.
Terse writing style is
strongly discouraged.
6.5.4.2.2. Boolean templates
The short description should be phrased in the form of a question which should
be kept short and should generally end with a question mark.
Terse writing
style is permitted and even encouraged if the question is rather long (remember
that translations are often longer than original versions).
Again, please avoid referring to specific interface widgets.
A common mistake
for such templates is if you answer Yes-type constructions.
6.5.4.2.3. Select/Multiselect
The short description is a prompt and not a
Do not use useless Please choose...
constructions.
Users are clever enough to figure out they have to choose
something...:)
The extended description will complete the short description.
It may refer to
the available choices.
It may also mention that the user may choose more than
one of the available choices, if the template is a multiselect one (although
the interface often makes this clear).
6.5.4.2.4. Notes
The short description should be considered to be a title.
The extended description is what will be displayed as a more detailed
explanation of the note.
Phrases, no terse writing style.
Do not abuse debconf. Notes are the most
common way to abuse debconf.
As written in debconf-devel manual page: it's
best to use them only for warning about very serious problems.
The NEWS.Debian
or README.Debian files are the appropriate location for a lot of notes.
reading this, you consider converting your Note type templates to entries in
NEWS.Debian or README.Debian, plus consider keeping existing translations for
the future.
6.5.4.3. Choices field
If the Choices are likely to change often, please consider using the __Choices
This will split each individual choice into a single string, which will
considerably help translators for doing their work.
6.5.4.4. Default field
If the default value, for a select template, is likely to vary depending on the
user language (for instance, if the choice is a language choice), please use
the _Default trick.
This special field allow translators to put the most appropriate choice
according to their own language.
It will become the default choice when their
language is used while your own mentioned Default Choice will be used when
using English.
Example, taken from the geneweb package templates:
Template: geneweb/lang
Type: select
__Choices: Afrikaans (af), Bulgarian (bg), Catalan (ca), Chinese (zh), Czech (cs), Danish (da), Dutch (nl), English (en), Esperanto (eo), Estonian (et), Finnish (fi), French (fr), German (de), Hebrew (he), Icelandic (is), Italian (it), Latvian (lv), Norwegian (no), Polish (pl), Portuguese (pt), Romanian (ro), Russian (ru), Spanish (es), Swedish (sv)
# This is the default choice. Translators may put their own language here
# instead of the default.
# WARNING : you MUST use the ENGLISH NAME of your language
# For instance, the french translator will need to put French (fr) here.
_Default: English[ translators, please see comment in PO files]
_Description: Geneweb default language:
Note the use of brackets which allow internal comments in debconf fields.
note the use of comments which will show up in files the translators will work
The comments are needed as the _Default trick is a bit confusing: the
translators may put their own choice
6.5.4.5. Default field
Do NOT use empty default field.
If you don't want to use default values, do
not use Default at all.
If you use po-debconf (and you should, see
), consider making this field translatable, if you think it may be
translated.
If the default value may vary depending on language/country (for instance the
default value for a language choice), consider using the special _Default
type documented in po-debconf(7).
6.6. Internationalization
This section contains global information for developers to make translators'
life easier.
More information for translators and developers interested
in internationalization are available in the
documentation.
6.6.1. Handling debconf translations
Like porters, translators have a difficult task.
They work on many packages
and must collaborate with many different maintainers.
Moreover, most of the
time, they are not native English speakers, so you may need to be particularly
patient with them.
The goal of debconf was to make
packages configuration easier for maintainers and for users.
Originally,
translation of debconf templates was handled with
debconf-mergetemplate.
However, that technique is now
the best way to accomplish debconf internationalization is by using the
po-debconf package.
This method is
easier both for mainta transition scripts are provided.
Using po-debconf, the translation is
stored in .po files (drawing from
gettext translation techniques).
Special template files
contain the original messages and mark which fields are translatable.
change the value of a translatable field, by calling
debconf-updatepo, the translation is marked as needing
attention from the translators.
Then, at build time, the
dh_installdebconf program takes care of all the needed magic
to add the template along with the up-to-date translations into the binary
Refer to the po-debconf(7) manual page for details.
6.6.2. Internationalized documentation
Internationalizing documentation is crucial for users, but a lot of labor.
There's no way to eliminate all that work, but you can make things easier for
translators.
If you maintain documentation of any size, it is easier for translators if they
have access to a source control system.
That lets translators see the
differences between two versions of the documentation, so, for instance, they
can see what needs to be retranslated.
It is recommended that the translated
documentation maintain a note about what source control revision the
translation is based on.
An interesting system is provided by
debian-installer package, which shows an
overview of the translation status for any given language, using structured
comments for the current revision of the file to be translated and, for a
translated file, the revision of the original file the translation is based on.
You might wish to adapt and provide that in your VCS area.
If you maintain XML or SGML documentation, we suggest that you isolate any
language-independent information and define those as entities in a separate
file which is included by all the different translations.
This makes it much
easier, for instance, to keep URLs up to date across multiple files.
Some tools (e.g. po4a, poxml, or the translate-toolkit) are specialized in extracting
the translatable material from different formats.
They produce PO files, a
format quite common to translators, which permits to see what needs to be
retranslated when the translated document is updated.
6.7. Common packaging situations6.7.1. Packages using autoconf/automake
Keeping autoconf's config.sub and
config.guess files up to date is critical for porters,
especially on more volatile architectures.
Some very good packaging practices
for any package using autoconf and/or
automake have been synthesized in
/usr/share/doc/autotools-dev/README.Debian.gz from the
autotools-dev package.
You're strongly
encouraged to read this file and to follow the given recommendations.
6.7.2. Libraries
Libraries are always difficult to package for various reasons.
The policy
imposes many constraints to ease their maintenance and to make sure upgrades
are as simple as possible when a new upstream version comes out.
Breakage in a
library can result in dozens of dependent packages breaking.
Good practices for library packaging have been grouped in .
6.7.3. Documentation
Be sure to follow the .
If your package contains documentation built from XML or SGML, we recommend you
not ship the XML or SGML source in the binary package(s).
If users want the
source of the documentation, they should retrieve the source package.
Policy specifies that documentation should be shipped in HTML format.
recommend shipping documentation in PDF and plain text format if convenient and
if output of reasonable quality is possible.
However, it is generally not
appropriate to ship plain text versions of documentation whose source format is
Major shipped manuals should register themselves with doc-base on installation.
See the doc-base package documentation for more
information.
Debian policy (section 12.1) directs that manual pages should accompany every
program, utility, and function, and suggests them for other objects like
configuration files. If the work you are packaging does not have such manual
pages, consider writing them for inclusion in your package, and submitting them
The manpages do not need to be written directly in the troff format.
source formats are Docbook, POD and reST, which can be converted using
xsltproc, pod2man and
rst2man respectively. To a lesser extent, the
help2man program can also be used to write a stub.
6.7.4. Specific types of packages
Several specific types of packages have special sub-policies and corresponding
packaging rules and practices:
Perl related packages have a , some examples of packages following that policy are libdbd-pg-perl (binary perl module) or libmldbm-perl (arch independent perl module).
Python related packages have see
/usr/share/doc/python/python-policy.txt.gz in the python package.
Emacs related packages have the .
Java related packages have their .
Ocaml related packages have their own policy, found in
/usr/share/doc/ocaml/ocaml_packaging_policy.gz from the ocaml package.
A good example is the camlzip source package.
Packages providing XML or SGML DTDs should conform to the recommendations found
in the sgml-base-doc package.
Lisp packages should register themselves with common-lisp-controller, about which see
/usr/share/doc/common-lisp-controller/README.packaging.
6.7.5. Architecture-independent data
It is not uncommon to have a large amount of architecture-independent data
packaged with a program.
For example, audio files, a collection of icons,
wallpaper patterns, or other graphic files.
If the size of this data is
negligible compared to the size of the rest of the package, it's probably best
to keep it all in a single package.
However, if the size of the data is considerable, consider splitting it out
into a separate, architecture-independent package (_all.deb).
By doing this,
you avoid needless duplication of the same data into eleven or more .debs, one
per each architecture.
While this adds some extra overhead into the
Packages files, it saves a lot of disk space on Debian
Separating out architecture-independent data also reduces processing
time of lintian (see ) when run over the entire Debian archive.
6.7.6. Needing a certain locale during build
If you need a certain locale during build, you can create a temporary file via
this trick:
If you set LOCPATH to the equivalent of /usr/lib/locale, and LC_ALL to the name
of the locale you generate, you should get what you want without being root.
Something like this:
LOCALE_PATH=debian/tmpdir/usr/lib/locale
LOCALE_NAME=en_IN
LOCALE_CHARSET=UTF-8
mkdir -p $LOCALE_PATH
localedef -i $LOCALE_NAME.$LOCALE_CHARSET -f $LOCALE_CHARSET $LOCALE_PATH/$LOCALE_NAME.$LOCALE_CHARSET
# Using the locale
LOCPATH=$LOCALE_PATH LC_ALL=$LOCALE_NAME.$LOCALE_CHARSET date
6.7.7. Make transition packages deborphan compliant
Deborphan is a program for helping users to detect which packages can safely be
removed from the system, i.e.
the ones that have no packages depending on
The default operation is to search only within the libs and oldlibs
sections, to hunt down unused libraries.
But when passed the right argument,
it tries to catch other useless packages.
For example, with --guess-dummy, deborphan
tries to search all transitional packages which were needed for upgrade but
which can now safely be removed.
For that, it looks for the string dummy or transitional in their short
description.
So, when you are creating such a package, please make sure to add this text to
your short description.
If you are looking for examples, just run:
apt-cache search .|grep dummy or
apt-cache search .|grep transitional.
Also, it is recommended to adjust its section to
and its priority to
in order to ease deborphan's job.
6.7.8. Best practices for .orig.tar.{gz,bz2,xz} files
There are two kinds of original source tarballs: Pristine source and repackaged
upstream source.
6.7.8.1. Pristine source
The defining characteristic of a pristine source tarball is that the
.orig.tar.{gz,bz2,xz} file is byte-for-byte identical to a tarball officially
distributed by the upstream author. This makes it
possible to use checksums to easily verify that all changes between Debian's
version and upstream's are contained in the Debian diff.
Also, if the original
source is huge, upstream authors and others who already have the upstream
tarball can save download time if they want to inspect your packaging in
There is no universally accepted guidelines that upstream authors follow
regarding to the directory structure inside their tarball, but
dpkg-source is nevertheless able to deal with most upstream
tarballs as pristine source.
Its strategy is equivalent to the following:
It unpacks the tarball in an empty temporary directory by doing
zcat path/to/packagename_upstream-version.orig.tar.gz | tar xf -
If, after this, the temporary directory contains nothing but one directory and
no other files, dpkg-source renames that directory to
packagename-upstream-version(.orig).
name of the top-level directory in the tarball does not matter, and is
forgotten.
Otherwise, the upstream tarball must have been packaged without a common
top-level directory (shame on the upstream author!).
In this case,
dpkg-source renames the temporary directory
packagename-upstream-version(.orig).
6.7.8.2. Repackaged upstream source
You should upload packages with a pristine
source tarball if possible, but there are various reasons why it might not be
This is the case if upstream does not distribute the source as
gzipped tar at all, or if upstream's tarball contains non-DFSG-free material
that you must remove before uploading.
In these cases the developer must construct a suitable .orig.tar.{gz,bz2,xz}
file themselves.
We refer to such a tarball as a repackaged upstream
Note that a repackaged upstream source is different from a
Debian-native package.
A repackaged source still comes with Debian-specific
changes in a separate .diff.gz or .debian.tar.{gz,bz2,xz}
and still has a version number composed of upstream-version and
debian-version.
There may be cases where it is desirable to repackage the source even though
upstream distributes a .tar.{gz,bz2,xz} that could in principle be
used in its pristine form.
The most obvious is if
significant space savings can be achieved by recompressing
the tar archive or by removing genuinely useless cruft from the upstream
Use your own discretion here, but be prepared to defend your decision
if you repackage source that could have been pristine.
A repackaged .orig.tar.{gz,bz2,xz}
should be documented in the resulting source package.
Detailed information on how the repackaged source was obtained,
and on how this can be reproduced should be provided in
debian/copyright.
It is also a good idea to provide a
get-orig-source target in your
debian/rules file that repeats the process, as described
in the Policy Manual, .
should not contain any file that does not
come from the upstream author(s), or whose contents has been changed by
should, except where impossible for legal
reasons, preserve the entire building and portablility infrastructure provided
by the upstream author.
For example, it is not a sufficient reason for
omitting a file that it is used only when building on MS-DOS.
Similarly, a
Makefile provided by upstream should not be omitted even if the first thing
your debian/rules does is to overwrite it by running a
configure script.
(Rationale: It is common for Debian users who need to
build software for non-Debian platforms to fetch the source from a Debian
mirror rather than trying to locate a canonical upstream distribution point).
should use
packagename-upstream-version.orig as the
name of the top-level directory in its tarball.
This makes it possible to
distinguish pristine tarballs from repackaged ones.
should be gzipped or bzipped with maximal compression.
6.7.8.3. Changing binary files
Sometimes it is necessary to change binary files contained in the original
tarball, or to add binary files that are not in it. This is fully supported
when using source packages in “3.0 (quilt)” format, see the
dpkg-source(1)
manual page for details. When using the older format “1.0”, binary files
can't be stored in the .diff.gz so you must store
an uuencoded (or similar) version of the file(s)
and decode it at build time in debian/rules (and move
it in its official location).
6.7.9. Best practices for debug packages
A debug package is a package with a name ending in -dbg, that contains
additional information that gdb can use.
Since Debian binaries are stripped by
default, debugging information, including function names and line numbers, is
otherwise not available when running gdb on Debian binaries.
Debug packages
allow users who need this additional debugging information to install it,
without bloating a regular system with the information.
It is up to a package's maintainer whether to create a debug package or not.
Maintainers are encouraged to create debug packages for library packages, since
this can aid in debugging many programs linked to a library.
In general, debug
packages do not need to be ad doing so would bloat the
But if a maintainer finds that users often need a debugging version
of a program, it can be worthwhile to make a debug package for it.
that are core infrastructure, such as apache and the X server are also good
candidates for debug packages.
Some debug packages may contain an entire special debugging build of a library
or other binary, but most of them can save space and build time by instead
containing separated debugging symbols that gdb can find and load on the fly
when debugging a program or library.
The convention in Debian is to keep these
symbols in /usr/lib/debug/path, where
path is the path to the executable or library.
example, debugging symbols for /usr/bin/foo go in
/usr/lib/debug/usr/bin/foo, and debugging symbols for
/usr/lib/libfoo.so.1 go in
/usr/lib/debug/usr/lib/libfoo.so.1.
The debugging symbols can be extracted from an object file using
objcopy --only-keep-debug.
Then the object file can be stripped,
and objcopy --add-gnu-debuglink used to specify the path
to the debugging symbol file.
objcopy(1) explains in detail how this works.
The dh_strip command in debhelper supports creating debug
packages, and can take care of using objcopy to separate
out the debugging symbols for you.
If your package uses debhelper, all you
need to do is call dh_strip --dbg-package=libfoo-dbg, and
add an entry to debian/control for the debug package.
Note that the debug package should depend on the package that it provides
debugging symbols for, and this dependency should be versioned.
For example:
Depends: libfoo (= ${binary:Version})
6.7.10. Best practices for meta-packages
A meta-package is a mostly empty package that makes it easy to install a
coherent set of packages that can evolve over time. It achieves this by
depending on all the packages of the set. Thanks to the power of APT, the
meta-package maintainer can adjust the dependencies and the user's system
will automatically get the supplementary packages. The dropped packages
that were automatically installed will be also be marked as removal
candidates (and are even automatically removed by aptitude).
linux-image-amd64 are two examples
of meta-packages (built by the source packages
meta-gnome2 and
linux-latest).
The long description of the meta-package must clearly document its purpose
so that the user knows what they will lose if they remove the package. Being
explicit about the consequences is recommended. This is particularly
important for meta-packages which are installed during initial
installation and that have not been explicitly installed by the user.
Those tend to be important to ensure smooth system upgrades and
the user should be discouraged from uninstalling them to avoid
potential breakages.