<tt>/usr/share/common-licenses/GPL</tt> in the Debian GNU/Linux
distribution or on the World Wide Web at
<url id="http://www.gnu.org/copyleft/gpl.html"
- name="The GNU General Public Licence">. You can also obtain it by writing to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
+ name="The GNU General Public Licence">. You can also
+ obtain it by writing to the Free Software Foundation, Inc.,
+ 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
</p>
</copyright>
</titlepag>
interfaces not changing, and the package
management software authors need to ensure
compatibility with these interface
- definitions. (Control file and and changelog file
+ definitions. (Control file and changelog file
formats are examples.)
</p>
</item>
<em>may</em>, and the adjectives <em>required</em>,
<em>recommended</em> and <em>optional</em>, are used to
distinguish the significance of the various guidelines in
- this policy document. Packages that do not conform the the
+ this policy document. Packages that do not conform to the
guidelines denoted by <em>must</em> (or <em>required</em>)
will generally not be considered acceptable for the Debian
distribution. Non-conformance with guidelines denoted by
<p>
Every package must be accompanied by a verbatim copy of
its copyright and distribution license in the file
- <tt>/usr/share/doc/<em><package-name></em>/copyright</tt>
+ <tt>/usr/share/doc/<em><package></em>/copyright</tt>
(see <ref id="copyrightfile"> for further details).
</p>
<p>
<item>
<p>
These packages provide a reasonably small but not too
- limited character-mode system. This is what will
- install by default if the user doesn't select anything
+ limited character-mode system. This is what will be
+ installed by default if the user doesn't select anything
else. It doesn't include many large applications, but
it does include Emacs (this is more of a piece of
infrastructure than an application) and a reasonable
<sect>
<heading>Source packages</heading>
- <sect1>
+ <sect1 id="standardsversion">
<heading>Standards conformance</heading>
- <sect id="standardsversion">
<p>
In the source package's <tt>Standards-Version</tt> control
format.
</p>
- <sect><heading>Syntax of control files</heading>
+ <sect id="controlsyntax"><heading>Syntax of control files</heading>
<p>
A control file consists of one or more paragraphs of fields.
<p>
The architectures we build on and build for are determined
- by <prgn>make</prgn> variables using
+ by <prgn>make</prgn> variables using the utility
<prgn>dpkg-architecture</prgn>. You can determine the
Debian architecture and the GNU style architecture
specification string for the build machine (the machine type
Though there is nothing stopping an author who is also
the Debian maintainer from using it for all their
changes, it will have to be renamed if the Debian and
- upstream maintainers become different
- people.
+ upstream maintainers become different people. In such a
+ case, however, it might be better to maintain the
+ package as a non-native package.
</p>
</footnote>.
</p>
<p>
That format is a series of entries like this:
<example>
- <var>package</var> (<var>version</var>) <var>distribution(s)</var>; urgency=<var>urgency</var>
+<var>package</var> (<var>version</var>) <var>distribution(s)</var>; urgency=<var>urgency</var>
- * <var>change details</var>
- <var>more change details</var>
- * <var>even more change details</var>
+ * <var>change details</var>
+ <var>more change details</var>
+ * <var>even more change details</var>
- -- <var>maintainer name and email address</var> <var>date</var>
+ -- <var>maintainer name and email address</var> <var>date</var>
</example>
</p>
<prgn>dpkg</prgn> changelog format (though there is
currently only one useful <var>keyword</var>,
<tt>urgency</tt>).
+ <footnote>
+ <p>
+ Usual urgency values are <tt>low</tt>, <tt>medium</tt>,
+ <tt>high</tt> and <tt>critical</tt>. They have an
+ effect on how quickly a package will be considered for
+ inclusion into the <tt>testing</tt> distribution, and
+ give an indication of the importance of any fixes
+ included in this upload.
+ </p>
+ </footnote>
</p>
<p>
</p>
<p>
- The maintainer name and email address need <em>not</em>
- necessarily be those of the usual package maintainer.
- They should be the details of the person doing
- <em>this</em> version. The information here will be
- copied to the <tt>.changes</tt> file, and then later used
- to send an acknowledgement when the upload has been
- installed.
+ If this upload resolves bugs recorded in the Bug Tracking
+ System (BTS), they may be automatically closed on the
+ inclusion of this package into the Debian archive by
+ including the string: <tt>closes: Bug#<var>nnnnn</var></tt>
+ in the change details.
+ <footnote>
+ <p>
+ To be precise, the string should match the following
+ Perl regular expression:
+ <tt>/closes:\s*(?:bug)?\#?\s?\d+(?:,\s*(?:bug)?\#?\s?\d+)*/i</tt>
+ Then all of the bug numbers listed will be closed by the
+ archive maintenance script (<prgn>katie</prgn>), or in
+ the case of an NMU, marked as fixed.
+ </p>
+ </footnote>
+ </p>
+
+ <p>
+ The maintainer name and email address used in the changelog
+ should be the details of the person uploading <em>this</em>
+ version. They are <em>not</em> necessarily those of the
+ usual package maintainer. The information here will be
+ copied to the <tt>Changed-By</tt> field in the
+ <tt>.changes</tt> file, and then later used to send an
+ acknowledgement when the upload has been installed.
</p>
<p>
</p>
</footnote>; it should include the time zone specified
numerically, with the time zone name or abbreviation
- optionally present as a comment.
+ optionally present as a comment in parentheses.
</p>
<p>
<p>
When <prgn>dpkg-gencontrol</prgn>,
<prgn>dpkg-genchanges</prgn> and <prgn>dpkg-source</prgn>
- generate control files they do variable substitutions on
- their output just before writing it. Variable
+ generate control files they perform variable substitutions
+ on their output just before writing it. Variable
substitutions have the form
<tt>${<var>variable-name</var>}</tt>. The optional file
- <tt>debian/substvars</tt> contains variable substitutions
- to be used; variables can also be set directly from
+ <tt>debian/substvars</tt> contains variable substitutions to
+ be used; variables can also be set directly from
<tt>debian/rules</tt> using the <tt>-V</tt> option to the
- source packaging commands, and certain predefined
- variables are available.
+ source packaging commands, and certain predefined variables
+ are also available.
</p>
<p>
- The is usually generated and modified dynamically by
- <tt>debian/rules</tt> targets; in this case it must be
- removed by the <prgn>clean</prgn> target.
+ The <tt>debian/substvars</tt> file is usually generated and
+ modified dynamically by <tt>debian/rules</tt> targets; in
+ this case it must be removed by the <prgn>clean</prgn>
+ target.
</p>
<p>
</p>
<p>
- <prgn>dpkg-gencontrol</prgn> adds an entry to this file
- for the <tt>.deb</tt> file that will be created by
- <prgn>dpkg-deb</prgn> from the control file that it
- generates, so for most packages all that needs to be done
- with this file is to delete it in <prgn>clean</prgn>.
+ When <prgn>dpkg-gencontrol</prgn> is run for a binary
+ package, it adds an entry to <tt>debian/files</tt> for the
+ <tt>.deb</tt> file that will be created when <prgn>dpkg-deb
+ --build</prgn> is run for that binary package. So for most
+ packages all that needs to be done with this file is to
+ delete it in the <prgn>clean</prgn> target.
</p>
<p>
packages, but only when extracting
them.
</p>
- </footnote>
- <footnote>
<p>
Hard links may be permitted at some point in the
future, but would require a fair amount of
</p>
<p>
- These scripts should be the files <tt>preinst</tt>,
+ These scripts are the files <tt>preinst</tt>,
<tt>postinst</tt>, <tt>prerm</tt> and <tt>postrm</tt> in the
control area of the package. They must be proper executable
- files; if they are scripts (which is recommended) they must
+ files; if they are scripts (which is recommended), they must
start with the usual <tt>#!</tt> convention. They should be
readable and executable by anyone, and not world-writable.
</p>
well.
</p>
- <p>
- It is necessary for the error recovery procedures that the
- scripts be idempotent: i.e., invoking the same script several
- times in the same situation should do no harm. If the first
- call failed, or aborted half way through for some reason,
- the second call should merely do the things that were left
- undone the first time, if any, and exit with a success
- status.
- </p>
-
<p>
When a package is upgraded a combination of the scripts from
- the old and new packages is called in amongst the other
- steps of the upgrade procedure. If your scripts are going
- to be at all complicated you need to be aware of this, and
- may need to check the arguments to your scripts.
+ the old and new packages is called during the upgrade
+ procedure. If your scripts are going to be at all
+ complicated you need to be aware of this, and may need to
+ check the arguments to your scripts.
</p>
<p>
<prgn>postrm</prgn> afterwards.
</p>
- <p> Programs called from maintainer scripts should not
- normally have a path prepended to them. Before installation
- is started the package management system checks to see if
- the programs <prgn>ldconfig</prgn>,
+ <p>
+ Programs called from maintainer scripts should not normally
+ have a path prepended to them. Before installation is
+ started, the package management system checks to see if the
+ programs <prgn>ldconfig</prgn>,
<prgn>start-stop-daemon</prgn>, <prgn>install-info</prgn>,
and <prgn>update-rc.d</prgn> can be found via the
<tt>PATH</tt> environment variable. Those programs, and any
- other program that one would expect to on the <tt>PATH</tt>,
- should thus be invoked without an absolute
+ other program that one would expect to be on the
+ <tt>PATH</tt>, should thus be invoked without an absolute
pathname. Maintainer scripts should also not reset the
- <tt>PATH</tt>, though they might choose to modify it by pre-
- or appending package-specific directories. These
+ <tt>PATH</tt>, though they might choose to modify it by
+ prepending or appending package-specific directories. These
considerations really apply to all shell scripts.</p>
</sect>
+
<sect>
<heading>Maintainer scripts Idempotency</heading>
<p>
- It is very important to make maintainer scripts
- idempotent.
- <footnote>
+ It is necessary for the error recovery procedures that the
+ scripts be idempotent. This means that if it is run
+ successfully, and then it is called again, it doesn't bomb
+ out or cause any harm, but just ensures that everything is
+ the way it ought to be. If the first call failed, or
+ aborted half way through for some reason, the second call
+ should merely do the things that were left undone the first
+ time, if any, and exit with a success status if everything
+ is OK.
+ <footnote>
<p>
- That means that if it runs successfully or fails
- and then you call it again it doesn't bomb out,
- but just ensures that everything is the way it
- ought to be.
+ This is so that if an error occurs, the user interrupts
+ <prgn>dpkg</prgn> or some other unforeseen circumstance
+ happens you don't leave the user with a badly-broken
+ package when <prgn>dpkg</prgn> attempts to repeat the
+ action.
</p>
- </footnote> This is so that if an error occurs, the
- user interrupts <prgn>dpkg</prgn> or some other
- unforeseen circumstance happens you don't leave the
- user with a badly-broken package.
+ </footnote>
</p>
</sect>
+
<sect>
<heading>Controlling terminal for maintainer scripts</heading>
</item>
<item>
<p><var>old-postinst</var> <tt>abort-upgrade</tt>
- <var>new version</var></p>
+ <var>new-version</var></p>
</item>
<item>
<p><var>conflictor's-postinst</var> <tt>abort-remove</tt>
The procedure on installation/upgrade/overwrite/disappear
(i.e., when running <tt>dpkg --unpack</tt>, or the unpack
stage of <tt>dpkg --install</tt>) is as follows. In each
- case if an error occurs the actions are, in general, run
- backwards - this means that the maintainer scripts are run
- with different arguments in reverse order. These are the
- `error unwind' calls listed below.
+ case, if a major error occurs (unless listed below) the
+ actions are, in general, run backwards - this means that the
+ maintainer scripts are run with different arguments in
+ reverse order. These are the `error unwind' calls listed
+ below.
<enumlist>
<item>
<example>
<var>new-preinst</var> install
</example>
- Error unwind versions, respectively:
+ Error unwind actions, respectively:
<example>
<var>new-postrm</var> abort-upgrade <var>old-version</var>
<var>new-postrm</var> abort-install <var>old-version</var>
The new package's files are unpacked, overwriting any
that may be on the system already, for example any
from the old version of the same package or from
- another package (backups of the old files are left
- around, and if anything goes wrong the package
+ another package. Backups of the old files are kept
+ temporarily, and if anything goes wrong the package
management system will attempt to put them back as
- part of the error unwind).
+ part of the error unwind.
</p>
<p>
It is an error for a package to contains files which
are on the system in another package, unless
<tt>Replaces</tt> is used (see <ref id="replaces">).
- Currently the <tt>--force-overwrite</tt> flag is
+ <!--
+ The following paragraph is not currently the case:
+ Currently the <tt>- - force-overwrite</tt> flag is
enabled, downgrading it to a warning, but this may not
always be the case.
+ -->
</p>
<p>
<p>
Packages which overwrite each other's files produce
- behavior which though deterministic is hard for the
+ behavior which, though deterministic, is hard for the
system administrator to understand. It can easily
lead to `missing' programs if, for example, a package
is installed which overwrites a file from another
</p>
<p>
- A directory will never be replaced by a symbolic links
+ A directory will never be replaced by a symbolic link
to a directory or vice versa; instead, the existing
state (symlink or not) will be left alone and
<prgn>dpkg</prgn> will follow the symlink if there is
<p>Any packages all of whose files have been overwritten during the
installation, and which aren't required for
dependencies, are considered to have been removed.
- For each such package,
+ For each such package
<enumlist>
<item>
<p><prgn>dpkg</prgn> calls:
<item>
<p>
The new package's status is now sane, and recorded as
- `unpacked'. Here is another point of no return - if
- the conflicting package's removal fails we do not
- unwind the rest of the installation; the conflicting
- package is left in a half-removed limbo.
+ `unpacked'.
+ </p>
+
+ <p>
+ Here is another point of no return - if the
+ conflicting package's removal fails we do not unwind
+ the rest of the installation; the conflicting package
+ is left in a half-removed limbo.
</p>
</item>
+
<item>
<p>
If there was a conflicting package we go and do the
<p>
When we configure a package (this happens with <tt>dpkg
--install</tt>, or with <tt>--configure</tt>), we first
- update the conffiles and then call:
+ update any <tt>conffile</tt>s and then call:
<example>
<var>postinst</var> configure <var>most-recently-configured-version</var>
</example>
</item>
<item>
<p>
- The package's files are removed (except conffiles).
+ The package's files are removed (except <tt>conffile</tt>s).
</p>
</item>
<item>
</example></p>
</item>
<item>
- <p>All the maintainer scripts except the postrm are removed.
+ <p>
+ All the maintainer scripts except the <tt>postrm</tt>
+ are removed.
</p>
<p>
If we aren't purging the package we stop here. Note
- that packages which have no postrm and no conffiles
- are automatically purged when removed, as there is no
- difference except for the <prgn>dpkg</prgn>
- status.</p>
+ that packages which have no <tt>postrm</tt> and no
+ <tt>conffile</tt>s are automatically purged when
+ removed, as there is no difference except for the
+ <prgn>dpkg</prgn> status.</p>
</item>
<item>
<p>
</item>
</enumlist>
No attempt is made to unwind after errors during
- removal.</p>
+ removal.
+ </p>
</sect>
</chapt>
<chapt id="relationships"><heading>Declaring relationships between
- packages </heading>
+ packages</heading>
<p>
Packages can declare in their control file that they have
</p>
<p>
- This is done using the <tt>Depends</tt>, <tt>Recommends</tt>,
- <tt>Suggests</tt>, <tt>Enhances</tt>, <tt>Conflicts</tt>,
- <tt>Provides</tt> and <tt>Replaces</tt> control file fields.
+ This is done using the <tt>Depends</tt>, <tt>Pre-Depends</tt>,
+ <tt>Recommends</tt>, <tt>Suggests</tt>, <tt>Enhances</tt>,
+ <tt>Conflicts</tt>, <tt>Provides</tt> and <tt>Replaces</tt>
+ control file fields.
</p>
<p>
<p>
This is done using the <tt>Build-Depends</tt>,
- <tt>Build-Depends-Indep</tt>, <tt>Build-Conflicts</tt>, and
+ <tt>Build-Depends-Indep</tt>, <tt>Build-Conflicts</tt> and
<tt>Build-Conflicts-Indep</tt> control file fields.
</p>
control file fields of the package, which declare
dependencies on other packages, the package names listed may
also include lists of alternative package names, separated
- by vertical bar symbols <tt>|</tt> (pipe symbols). In such
- a case, the presence of any one of the alternative packages
- is installed, that part of the dependency is considered to
- be satisfied.
+ by vertical bar (pipe) symbols <tt>|</tt>. In such a case,
+ if any one of the alternative packages is installed, that
+ part of the dependency is considered to be satisfied.
</p>
<p>
- All the fields except <tt>Provides</tt> may restrict their
- applicability to particular versions of each named package.
- This is done in parentheses after each individual package
- name; the parentheses should contain a relation from the
- list below followed by a version number, in the format
+ All of the fields except for <tt>Provides</tt> may restrict
+ their applicability to particular versions of each named
+ package. This is done in parentheses after each individual
+ package name; the parentheses should contain a relation from
+ the list below followed by a version number, in the format
described in <ref id="versions">.
</p>
The relations allowed are <tt><<</tt>, <tt><=</tt>,
<tt>=</tt>, <tt>>=</tt> and <tt>>></tt> for
strictly earlier, earlier or equal, exactly equal, later or
- equal and strictly later, respectively. The forms
- <tt><</tt> and <tt>></tt> were used to mean
+ equal and strictly later, respectively. The deprecated
+ forms <tt><</tt> and <tt>></tt> were used to mean
earlier/later or equal, rather than strictly earlier/later,
so they should not appear in new packages (though
<prgn>dpkg</prgn> still supports them).
<p>
Whitespace may appear at any point in the version
- specification, and must appear where it's necessary to
+ specification subject to the rules in <ref
+ id="controlsyntax">, and must appear where it's necessary to
disambiguate; it is not otherwise significant. For
consistency and in case of future changes to
<prgn>dpkg</prgn> it is recommended that a single space be
used after a version relationship and before a version
- number; it is usual also to put a single space after each
- comma, on either side of each vertical bar, and before each
- open parenthesis.
+ number; it is also conventional to put a single space after
+ each comma, on either side of each vertical bar, and before
+ each open parenthesis.
</p>
<p>
- For example:
+ For example, a list of dependencies might appear as:
<example>
- Package: metamail
- Version: 2.7-3
- Depends: libc5 (>= 5.2.18-4), mime-support, csh | tcsh
+ Package: mutt
+ Version: 1.3.17-1
+ Depends: libc6 (>= 2.2.1), exim | mail-transport-agent
</example>
</p>
(<tt>Build-Depends</tt>, <tt>Build-Depends-Indep</tt>,
<tt>Build-Conflicts</tt> and <tt>Build-Conflicts-Indep</tt>)
may be restricted to a certain set of architectures. This
- is done in brackets after each individual package name and
+ is indicated in brackets after each individual package name and
the optional version specification. The brackets enclose a
list of Debian architecture names separated by whitespace.
Exclamation marks may be prepended to each of the names.
</p>
<p>
- All but <tt>Pre-Depends</tt> and <tt>Conflicts</tt>
- (discussed below) take effect <em>only</em> when a package
- is to be configured. They do not prevent a package being on
- the system in an unconfigured state while its dependencies
- are unsatisfied, and it is possible to replace a package
- whose dependencies are satisfied and which is properly
- installed with a different version whose dependencies are
- not and cannot be satisfied; when this is done the depending
- package will be left unconfigured (since attempts to
- configure it will give errors) and will not function
- properly.
+ A <tt>Depends</tt> field takes effect <em>only</em> when a
+ package is to be configured. It does not prevent a package
+ being on the system in an unconfigured state while its
+ dependencies are unsatisfied, and it is possible to replace
+ a package whose dependencies are satisfied and which is
+ properly installed with a different version whose
+ dependencies are not and cannot be satisfied; when this is
+ done the depending package will be left unconfigured (since
+ attempts to configure it will give errors) and will not
+ function properly. If it is necessary, a
+ <tt>Pre-Depends</tt> field can be used, which has a partial
+ effect even when a package is being unpacked, as explained
+ in detail below. (The other three dependency fields,
+ <tt>Recommends</tt>, <tt>Suggests</tt> and
+ <tt>Enhances</tt>, are only used by the various front-ends
+ to <prgn>dpkg</prgn> such as <prgn>dselect</prgn>.)
</p>
<p>
</p>
<p>
- Thus <tt>Depends</tt> allows package maintainers to impose
- an order in which packages should be configured.
+ The <tt>Depends</tt> field thus allows package maintainers
+ to impose an order in which packages should be configured.
+ </p>
+
+ <p>
+ The meaning of the five dependency fields is as follows:
<taglist>
<tag><tt>Depends</tt></tag>
<item>
- <p>This declares an absolute dependency.
+ <p>
+ This declares an absolute dependency. A package will
+ not be configured unless all of the packages listed in
+ its <tt>Depends</tt> field have been correctly
+ configured.
</p>
<p>
The <tt>Depends</tt> field should be used if the
depended-on package is required for the depending
package to provide a significant amount of
- functionality.</p>
+ functionality.
+ </p>
+ <p>
+ The <tt>Depends</tt> field should also be used if the
+ <prgn>postinst</prgn>, <prgn>prerm</prgn> or
+ <prgn>postrm</prgn> scripts require the package to be
+ present in order to run. Note, however, that the
+ <prgn>postrm</prgn> cannot rely on any non-essential
+ packages to be present during the <tt>purge</tt>
+ phase.
</item>
<tag><tt>Recommends</tt></tag>
also forces <prgn>dpkg</prgn> to complete installation
of the packages named before even starting the
installation of the package which declares the
- Pre-dependency.
+ pre-dependency, as follows:
</p>
<p>
- <tt>Pre-Depends</tt> should be used sparingly,
- preferably only by packages whose premature upgrade or
- installation would hamper the ability of the system to
- continue with any upgrade that might be in progress.
+ When a package declaring a pre-dependency is about to
+ be <em>unpacked</em> the pre-dependency can be
+ satisfied if the depended-on package is either fully
+ configured, <em>or even if</em> the depended-on
+ package(s) are only unpacked or half-configured,
+ provided that they have been configured correctly at
+ some point in the past (and not removed or partially
+ removed since). In this case, both the
+ previously-configured and currently unpacked or
+ half-configured versions must satisfy any version
+ clause in the <tt>Pre-Depends</tt> field.
</p>
<p>
- When the package declaring it is being configured, a
- <tt>Pre-Dependency</tt> will be considered satisfied
- only if the depending package has been correctly
- configured, just as if an ordinary <tt>Depends</tt>
- had been used.
+ When the package declaring a pre-dependency is about
+ to be <em>configured</em>, the pre-dependency will be
+ treated as a normal <tt>Depends</tt>, that is, it will
+ be considered satisfied only if the depended-on
+ package has been correctly configured.
</p>
<p>
- However, when a package declaring a Pre-dependency is
- being unpacked the predependency can be satisfied even
- if the depended-on package(s) are only unpacked or
- half-configured, provided that they have been
- configured correctly at some point in the past (and
- not removed or partially removed since). In this case
- both the previously-configured and currently unpacked
- or half-configured versions must satisfy any version
- clause in the <tt>Pre-Depends</tt> field.
+ <tt>Pre-Depends</tt> should be used sparingly,
+ preferably only by packages whose premature upgrade or
+ installation would hamper the ability of the system to
+ continue with any upgrade that might be in progress.
</p>
+
+ <p>
+ <tt>Pre-Depends</tt> are also required if the
+ <prgn>preinst</prgn> script depends on the named
+ package. It is best to avoid this situation if
+ possible.
</item>
</taglist>
</p>
</p>
- <sect id="conflicts"><heading>Alternative binary packages -
- <tt>Conflicts</tt> and <tt>Replaces</tt>
- </heading>
+ <sect id="conflicts"><heading>Conflicting binary packages -
+ <tt>Conflicts</tt></heading>
<p>
When one binary package declares a conflict with another
- <prgn>dpkg</prgn> will refuse to allow them to be installed
- on the system at the same time.
+ using a <tt>Conflicts</tt> field, <prgn>dpkg</prgn> will
+ refuse to allow them to be installed on the system at the
+ same time.
</p>
<p>
If one package is to be installed, the other must be removed
first - if the package being installed is marked as
- replacing (<ref id="replaces">) the one on the system, or
- the one on the system is marked as deselected, or both
+ replacing (see <ref id="replaces">) the one on the system,
+ or the one on the system is marked as deselected, or both
packages are marked <tt>Essential</tt>, then
<prgn>dpkg</prgn> will automatically remove the package
which is causing the conflict, otherwise it will halt the
- installation of the new package with an error. This
- mechanism specifically doesn't work when the installed
- package is <tt>Essential</tt>, but the new package is not.
+ installation of the new package with an error. This
+ mechanism is specifically designed to produce an error when
+ the installed package is <tt>Essential</tt>, but the new
+ package is not.
</p>
-
<p>
A package will not cause a conflict merely because its
configuration files are still installed; it must be at least
prevent their installation, and allows a package to conflict
with others providing a replacement for it. You use this
feature when you want the package in question to be the only
- package providing something.
+ package providing some feature.
</p>
<p>
<p>
As well as the names of actual (`concrete') packages, the
package relationship fields <tt>Depends</tt>,
+ <tt>Recommends</tt>, <tt>Suggests</tt>, <tt>Enhances</tt>,
+ <tt>Pre-Depends</tt>, <tt>Conflicts</tt>,
<tt>Build-Depends</tt>, <tt>Build-Depends-Indep</tt>,
- <tt>Recommends</tt>, <tt>Suggests</tt>, <tt>Conflicts</tt>,
- <tt>Build-Conflicts</tt> and <tt>Build-Conflicts-Indep</tt> may
- mention virtual packages.
+ <tt>Build-Conflicts</tt> and <tt>Build-Conflicts-Indep</tt>
+ may mention `virtual packages'.
</p>
<p>
- A virtual package is one which appears in the
+ A <em>virtual package</em> is one which appears in the
<tt>Provides</tt> control file field of another package.
The effect is as if the package(s) which provide a
particular virtual package name had been listed by name
packages which provide it. This is so that, for example,
supposing we have
<example>
- Package: vm
- Depends: emacs
+ Package: foo
+ Depends: bar
</example>
- and someone else releases an xemacs package they can say
+ and someone else releases an enhanced version of the
+ <tt>bar</tt> package (for example, a non-US variant), they
+ can say:
<example>
- Package: xemacs
- Provides: emacs
- </example> and all will work in the interim (until a purely
- virtual package name is decided on and the <tt>emacs</tt>
- and <tt>vm</tt> packages are changed to use it).
+ Package: bar-plus
+ Provides: bar
+ </example>
+ and the <tt>bar-plus</tt> package will now also satisfy the
+ dependency for the <tt>foo</tt> package.
</p>
<p>
</p>
<p>
- If you want to specify which of a set of real packages should be the
- default to satisfy a particular dependency on a virtual package, you
- should list the real package as an alternative before the virtual.
+ If you want to specify which of a set of real packages
+ should be the default to satisfy a particular dependency on
+ a virtual package, you should list the real package as an
+ alternative before the virtual one.
</p>
</sect>
- <sect id="replaces"><heading><tt>Replaces</tt> - overwriting
- files and replacing packages
- </heading>
-
- <p>
- The <tt>Replaces</tt> control file field has two purposes,
- which come into play in different situations.
- </p>
+ <sect id="replaces"><heading>Overwriting files and replacing
+ packages - <tt>Replaces</tt></heading>
<p>
- Virtual packages (<ref id="virtual">) are not considered
- when looking at a <tt>Replaces</tt> field - the packages
- declared as being replaced must be mentioned by their real
- names.
+ The <tt>Replaces</tt> control file field has two distinct
+ purposes, which come into play in different situations.
</p>
- <sect1><heading>Overwriting files in other packages
- </heading>
+ <sect1><heading>Overwriting files in other packages</heading>
<p>
Firstly, as mentioned before, it is usually an error for a
package to contain files which are on the system in
- another package, though currently the
- <tt>--force-overwrite</tt> flag is enabled by default,
- downgrading the error to a warning,
+ another package.
</p>
<p>
- If the overwriting package declares that it replaces the
- one containing the file being overwritten then
- <prgn>dpkg</prgn> will proceed, and replace the file from
- the old package with that from the new. The file will no
- longer be listed as `owned' by the old package.
+ However, if the overwriting package declares that it
+ <tt>Replaces</tt> the one containing the file being
+ overwritten, then <prgn>dpkg</prgn> will replace the file
+ from the old package with that from the new. The file
+ will no longer be listed as `owned' by the old package.
</p>
<p>
If a package is completely replaced in this way, so that
<prgn>dpkg</prgn> does not know of any files it still
- contains, it is considered to have disappeared. It will
+ contains, it is considered to have `disappeared'. It will
be marked as not wanted on the system (selected for
- removal) and not installed. Any conffiles details noted
- in the package will be ignored, as they will have been
- taken over by the replacing package(s). The package's
- <prgn>postrm</prgn> script will be run to allow the
- package to do any final cleanup required. See <ref
- id="mscriptsinstact">.
+ removal) and not installed. Any <tt>conffile</tt>s
+ details noted for the package will be ignored, as they
+ will have been taken over by the overwriting package. The
+ package's <prgn>postrm</prgn> script will be run with a
+ special argument to allow the package to do any final
+ cleanup required. See <ref id="mscriptsinstact">.
</p>
<p>
- In the future <prgn>dpkg</prgn> will discard files which
- would overwrite those from an already installed package
- which declares that it replaces the package being
- installed. This is so that you can install an older
- version of a package without problems.
+ If an installed package, <tt>foo</tt> say, declares that
+ it replaces another, <tt>bar</tt>, and an attempt is made
+ to install <tt>bar</tt>, <prgn>dpkg</prgn> will discard
+ files in the <tt>bar</tt> package which would overwrite
+ those already present in <tt>foo</tt>. This is so that
+ you can install an older version of a package without
+ problems.
</p>
<p>
- This usage of <tt>Replaces</tt> only takes effect when
- both packages are at least partially on the system at
- once, so that it can only happen if they do not conflict
- or if the conflict has been overridden.</p>
+ For this usage of <tt>Replaces</tt>, virtual packages (see
+ <ref id="virtual">) are not considered when looking at a
+ <tt>Replaces</tt> field - the packages declared as being
+ replaced must be mentioned by their real names.
+ </p>
+
+ <p>
+ Furthermore, this usage of <tt>Replaces</tt> only takes
+ effect when both packages are at least partially on the
+ system at once, so that it can only happen if they do not
+ conflict or if the conflict has been overridden.
+ </p>
+
</sect1>
<sect1><heading>Replacing whole packages, forcing their
- removal
- </heading>
+ removal</heading>
<p>
Secondly, <tt>Replaces</tt> allows the packaging system to
resolve which package should be removed when there is a
conflict - see <ref id="conflicts">. This usage only
takes effect when the two packages <em>do</em> conflict,
- so that the two effects do not interfere with each other.
+ so that the two usages of this field do not interfere with
+ each other.
</p>
+
+ <p>
+ In this situation, the package declared as being replaced
+ can be a virtual package, so for example, all mail
+ transport agents (MTAs) would have the following fields in
+ their control files:
+ <example>
+Provides: mail-transport-agent
+Conflicts: mail-transport-agent
+Replaces: mail-transport-agent
+ </example>
+ ensuring that only one MTA can be installed at any one
+ time.
</sect1>
</sect>
<p>
A source package may declare a dependency or a conflict on a
- binary package. This is done with the control file fields
- <tt>Build-Depends</tt>, <tt>Build-Depends-Indep</tt>,
- <tt>Build-Conflicts</tt>, and
- <tt>Build-Conflicts-Indep</tt>. Their semantics are that
- the dependencies and conflicts they define must be satisfied
- (as defined earlier for binary packages), when one of the
- targets in <tt>debian/rules</tt> that the particular field
- applies to is invoked.
+ binary package, indicating which packages are required to be
+ present on the system in order to build the binary packages
+ from the source package. This is done with the control file
+ fields <tt>Build-Depends</tt>, <tt>Build-Depends-Indep</tt>,
+ <tt>Build-Conflicts</tt> and <tt>Build-Conflicts-Indep</tt>.
+ The dependencies and conflicts they define must be satisfied
+ (as defined earlier for binary packages) in order to invoke
+ the targets in <tt>debian/rules</tt>, as follows:
<taglist>
<tag><tt>Build-Depends</tt>, <tt>Build-Conflicts</tt></tag>
<item>
<p>
The <tt>Build-Depends</tt> and
- <tt>Build-Conflicts</tt> fields apply to the targets
+ <tt>Build-Conflicts</tt> fields must be satisfied when
+ any of the following targets is invoked:
<tt>build</tt>, <tt>binary</tt>, <tt>binary-arch</tt>
and <tt>binary-indep</tt>.
</p>
<item>
<p>
The <tt>Build-Depends-Indep</tt> and
- <tt>Build-Conflicts-Indep</tt> fields apply to the
- targets <tt>binary</tt> and <tt>binary-indep</tt>.
+ <tt>Build-Conflicts-Indep</tt> fields must be
+ satisfied when any of the following targets is
+ invoked: <tt>binary</tt> and <tt>binary-indep</tt>.
</p>
</item>
</taglist>
</heading>
<p>
- <prgn>dpkg</prgn> can do a certain amount of automatic
- handling of package configuration files.
+ This chapter has been superseded by <ref id="config files">.
</p>
- <p>
- Whether this mechanism is appropriate depends on a number of
- factors, but basically there are two approaches to any
- particular configuration file.
- </p>
- <p>
- The easy method is to ship a best-effort configuration in the
- package, and use <prgn>dpkg</prgn>'s conffile mechanism to
- handle updates. If the user is unlikely to want to edit the
- file, but you need them to be able to without losing their
- changes, and a new package with a changed version of the file
- is only released infrequently, this is a good approach.
- </p>
-
- <p>
- The hard method is to build the configuration file from
- scratch in the <prgn>postinst</prgn> script, and to take the
- responsibility for fixing any mistakes made in earlier
- versions of the package automatically. This will be
- appropriate if the file is likely to need to be different on
- each system.
- </p>
-
-
- <chapt id="sharedlibs"><heading>Shared libraries
- </heading>
+ <chapt id="sharedlibs"><heading>Shared libraries</heading>
<p>
Packages containing shared libraries must be constructed with
a little care to make sure that the shared library is always
available. This is especially important for packages whose
- shared libraries are vitally important, such as the libc.
+ shared libraries are vitally important, such as the C library
+ (currently <tt>libc6</tt>).
</p>
<p>
- Firstly, your package should install the shared libraries
- under their normal names. For example, the
- <prgn>libgdbm1</prgn> package should install
- <tt>libgdbm.so.1.7.3</tt> as
+ Firstly, the package should install the shared libraries under
+ their normal names. For example, the <tt>libgdbmg1</tt>
+ package should install <tt>libgdbm.so.1.7.3</tt> as
<tt>/usr/lib/libgdbm.so.1.7.3</tt>. The files should not be
- renamed or re-linked by any prerm or postrm scripts;
- <prgn>dpkg</prgn> will take care of renaming things safely
- without affecting running programs, and attempts to interfere
- with this are likely to lead to problems.
+ renamed or re-linked by any <prgn>prerm</prgn> or
+ <prgn>postrm</prgn> scripts; <prgn>dpkg</prgn> will take care
+ of renaming things safely without affecting running programs,
+ and attempts to interfere with this are likely to lead to
+ problems.
</p>
<p>
- Secondly, your package should include the symlink that
+ Secondly, the package should include the symbolic link that
<prgn>ldconfig</prgn> would create for the shared libraries.
- For example, the <prgn>libgdbm1</prgn> package should include
- a symlink from <tt>/usr/lib/libgdbm.so.1</tt> to
- <tt>libgdbm.so.1.7.3</tt>. This is needed so that
- <prgn>ld.so</prgn> can find the library in between the time
- <prgn>dpkg</prgn> installs it and <prgn>ldconfig</prgn> is run
- in the <prgn>postinst</prgn> script. Furthermore, older
- versions of the package management system required the library
- must be placed before the symlink pointing to it in the
- <tt>.deb</tt> file. This is so that by the time
- <prgn>dpkg</prgn> comes to install the symlink (overwriting
- the previous symlink pointing at an older version of the
- library) the new shared library is already in place.
- Unfortunately, this was not not always possible, since it
- highly depends on the behavior of the file system. Some
- file systems (such as reiserfs) will reorder the files so it
- doesn't matter in what order you create them. Starting with
- release <tt>1.7.0</tt> <prgn>dpkg</prgn> will reorder the
- files itself when building a package.
+ For example, the <prgn>libgdbmg1</prgn> package should include
+ a symbolic link from <tt>/usr/lib/libgdbm.so.1</tt> to
+ <tt>libgdbm.so.1.7.3</tt>. This is needed so that the dynamic
+ linker (for example <prgn>ld.so</prgn> or
+ <prgn>ld-linux.so.*</prgn>) can find the library between the
+ time that <prgn>dpkg</prgn> installs it and the time that
+ <prgn>ldconfig</prgn> is run in the <prgn>postinst</prgn>
+ script.
+ <footnote>
+ <p>
+ The package management system requires the library to be
+ placed before the symbolic link pointing to it in the
+ <tt>.deb</tt> file. This is so that when
+ <prgn>dpkg</prgn> comes to install the symlink
+ (overwriting the previous symlink pointing at an older
+ version of the library), the new shared library is already
+ in place. In the past, this was achieved by creating the
+ library in the temporary packaging directory before
+ creating the symlink. Unfortunately, this was not always
+ effective, since the building of the tar file in the
+ <tt>.deb</tt> depended on the behavior of the underlying
+ file system. Some file systems (such as reiserfs) reorder
+ the files so that the order of creation is forgotten.
+ Starting with release <tt>1.7.0</tt>, <prgn>dpkg</prgn>
+ will reorder the files itself as necessary when building a
+ package. Thus it is no longer important to concern
+ oneself with the order of file creation.
+ </p>
+ </footnote>
</p>
<p>
- Thirdly, the development package should contain a symlink for
- the shared library without a version number. For example, the
- <tt>libgdbm1-dev</tt> package should include a symlink from
- <tt>/usr/lib/libgdm.so</tt> to <tt>libgdm.so.1.7.3</tt>. This
- symlink is needed by <prgn>ld</prgn> when compiling packages
- as it will only look for <tt>libgdm.so</tt> and
- <tt>libgdm.a</tt> when compiling dynamically or statically,
- respectively.
+ Thirdly, the associated development package should contain a
+ symlink for the shared library without a version number. For
+ example, the <tt>libgdbmg1-dev</tt> package should include a
+ symlink from <tt>/usr/lib/libgdbm.so</tt> to
+ <tt>libgdbm.so.1.7.3</tt>. This symlink is needed by the
+ linker (<prgn>ld</prgn>) when compiling packages, as it will
+ only look for <tt>libgdbm.so</tt> when compiling dynamically.
</p>
<p>
- Any package installing shared libraries in a directory that's listed
- in <tt>/etc/ld.so.conf</tt> or in one of the default library
- directories of <prgn>ld.so</prgn> (currently, these are <tt>/usr/lib</tt>
- and <tt>/lib</tt>) must call <prgn>ldconfig</prgn> in its <prgn>postinst</prgn>
- script if and only if the first argument is `configure'. However, it
- is important not to call <prgn>ldconfig</prgn> in the postrm or preinst
- scripts in the case where the package is being upgraded (see <ref
- id="unpackphase">), as <prgn>ldconfig</prgn> will see the temporary names
- that <prgn>dpkg</prgn> uses for the files while it is
- installing them and will make the shared library links point
- to them, just before <prgn>dpkg</prgn> continues the
- installation and removes the links!
+ Any package installing shared libraries in a directory that is
+ listed in <tt>/etc/ld.so.conf</tt> or in one of the default
+ library directories of the dynamic linker (currently, these
+ are <tt>/usr/lib</tt> and <tt>/lib</tt>) must call
+ <prgn>ldconfig</prgn> in its <prgn>postinst</prgn> script if
+ and only if the first argument is `configure'. However, it is
+ important not to call <prgn>ldconfig</prgn> in the postrm or
+ preinst scripts in the case where the package is being
+ upgraded (see <ref id="unpackphase">), as
+ <prgn>ldconfig</prgn> will see the temporary names that
+ <prgn>dpkg</prgn> uses for the files while it is installing
+ them and will make the shared library links point to them,
+ just before <prgn>dpkg</prgn> continues the installation and
+ removes the links!
</p>
<sect id="shlibs"><heading>The <tt>shlibs</tt> File Format
permissions 2775 (group-writable and set-group-id) and be
owned by <tt>root.staff</tt>.</p>
</sect1>
+ <sect1>
+ <heading>The system-wide mail directory</heading>
+ <p>
+ The system-wide mail directory is <tt>/var/mail</tt>. This
+ directory is part of the base system and should not owned
+ by any particular mail agents. The use of the old
+ location <tt>/var/spool/mail</tt> is deprecated, even
+ though the spool may still be physically located there.
+ To maintain partial upgrade compatibility for systems
+ which have <tt>/var/spool/mail</tt> as their physical mail
+ spool, packages using <tt>/var/mail</tt> must depend on
+ either <package>libc6</package> (>= 2.1.3-13), or on
+ <package>base-files</package> (>= 2.2.0), or on later
+ versions of either one of these packages.
+ </p>
+ </sect1>
+
</sect>
+
+
<sect>
<heading>Users and groups</heading>
<p>
If a certain job has to be executed more frequently than
daily, the package should install a file
- <tt>/etc/cron.d/<var>package-name</var></tt>. This file uses
+ <tt>/etc/cron.d/<var>package</var></tt>. This file uses
the same syntax as <tt>/etc/crontab</tt> and is processed by
<prgn>cron</prgn> automatically. The file must also be
treated as a configuration file. (Note, that entries in the
<p>
You should follow the directions in the <em>Debian Packaging
- Manual</em> for putting the shared library in its package,
- and you must include a <tt>shlibs</tt> control area
- file with details of the dependencies for packages which
- use the library.</p>
+ Manual</em> (or other documentation of the Debian
+ packaging tools) for putting the shared library in its
+ package, and you must include a <tt>shlibs</tt> control area
+ file with details of the dependencies for packages which use
+ the library.</p>
<p>
Shared libraries should not be installed
</sect>
</chapt>
- <chapt>
+ <chapt id="customized-programs">
<heading>Customized programs</heading>
<sect id="arch-spec">
</enumlist></p></sect>
- <sect>
+ <sect id="mail-transport-agents">
<heading>Mail transport, delivery and user agents</heading>
<p>
serious brain damage!</p>
<p>
- The mail spool is <tt>/var/spool/mail</tt> and the interface
+ The mail spool is <tt>/var/mail</tt> and the interface
to send a mail message is <tt>/usr/sbin/sendmail</tt> (as
- per the FHS). The mail spool is part of the base system
- and not part of the MTA package.</p>
+ per the FHS). On older systems, the mail spool may be
+ physically located in /var/spool/mail, but all access to the
+ mail spool should be via the /var/mail symlink. The mail
+ spool is part of the base system and not part of the MTA
+ package.
+ </p>
<p>
All Debian MUAs, MTAs, MDAs and other mailbox accessing
<item>
BDF fonts should be converted to PCF fonts with the
<tt>bdftopcf</tt> utility (available in the
- <tt>xutils</tt> package, <tt>gzip</tt>ped, and
+ <tt>xutils</tt> package), <tt>gzip</tt>ped, and
placed in a directory that corresponds to their
resolution:
<list>
</p>
</sect>
+ <sect>
+ <heading>Perl programs and modules</heading>
+ <p>
+ Perl programs and modules should follow the current Perl
+ policy as defined in the file found on
+ <ftpsite>ftp.debian.org</ftpsite> in
+ <ftppath>/debian/doc/package-developer/perl-policy.txt.gz</ftppath>
+ or your local mirror. In addition, it is included in the
+ <tt>debian-policy</tt> package.
+ </p>
+ </sect>
<sect>
<heading>Emacs lisp programs</heading>
<p>
Every package must be accompanied by a verbatim copy of its
copyright and distribution license in the file
- /usr/share/doc/<package-name>/copyright. This file must
+ /usr/share/doc/<package>/copyright. This file must
neither be compressed nor be a symbolic link.</p>
<p>
<p>
- /usr/share/doc/<package-name> may be a symbolic link to a
+ /usr/share/doc/<package> may be a symbolic link to a
directory in /usr/share/doc only if two packages both come from
the same source and the first package has a "Depends"
relationship on the second. These rules are important
projects / debian / debian-policy.git / blobdiff