X-Git-Url: https://git.saurik.com/apt.git/blobdiff_plain/fb2894d268d4821e0dd4f2b803ff2043b1ec3162..05f64ca2e483709faa6bc69dfa79129d2d4c679e:/doc/apt_preferences.5.xml diff --git a/doc/apt_preferences.5.xml b/doc/apt_preferences.5.xml index ab0107d36..16e6a7aa0 100644 --- a/doc/apt_preferences.5.xml +++ b/doc/apt_preferences.5.xml @@ -1,10 +1,9 @@ - -%aptent; - + %aptent; + %aptverbatiment; + %aptvendor; ]> @@ -14,12 +13,13 @@ &apt-email; &apt-product; - 29 February 2004 + 2012-06-09T00:00:00Z apt_preferences 5 + APT @@ -31,7 +31,8 @@ Description The APT preferences file /etc/apt/preferences -can be used to control which versions of packages will be selected +and the fragment files in the /etc/apt/preferences.d/ +folder can be used to control which versions of packages will be selected for installation. Several versions of a package may be available for installation when @@ -40,7 +41,7 @@ the &sources-list; file contains references to more than one distribution APT assigns a priority to each version that is available. Subject to dependency constraints, apt-get selects the version with the highest priority for installation. -The APT preferences file overrides the priorities that APT assigns to +The APT preferences override the priorities that APT assigns to package versions by default, thus giving the user control over which one is selected for installation. @@ -48,9 +49,29 @@ one is selected for installation. the &sources-list; file contains references to more than one source. In this case apt-get downloads the instance listed earliest in the &sources-list; file. -The APT preferences file does not affect the choice of instance, only +The APT preferences do not affect the choice of instance, only the choice of version. +Preferences are a strong power in the hands of a system administrator +but they can become also their biggest nightmare if used without care! +APT will not question the preferences, so wrong settings can +lead to uninstallable packages or wrong decisions while upgrading packages. +Even more problems will arise if multiple distribution releases are mixed +without a good understanding of the following paragraphs. +Packages included in a specific release aren't tested in (and +therefore don't always work as expected in) older or newer releases, or +together with other packages from different releases. +You have been warned. + +Note that the files in the /etc/apt/preferences.d +directory are parsed in alphanumeric ascending order and need to obey the +following naming convention: The files have either no or "pref" +as filename extension and only contain alphanumeric, hyphen (-), +underscore (_) and period (.) characters. +Otherwise APT will print a notice that it has ignored a file, unless that +file matches a pattern in the Dir::Ignore-Files-Silently +configuration list - in which case it will be silently ignored. + APT's Default Priority Assignments If there is no preferences file or if there is no entry in the file @@ -60,6 +81,9 @@ belongs. It is possible to single out a distribution, "the target release", which receives a higher priority than other distributions do by default. The target release can be set on the apt-get command line or in the APT configuration file /etc/apt/apt.conf. +Note that this has precedence over any general priority you set in the +/etc/apt/preferences file described later, but not +over specifically pinned packages. For example, @@ -74,9 +98,19 @@ APT::Default-Release "stable"; algorithm to set the priorities of the versions of a package. Assign: + +priority 1 +to the versions coming from archives which in their Release +files are marked as "NotAutomatic: yes" but not as "ButAutomaticUpgrades: yes" +like the Debian experimental archive. + + priority 100 -to the version that is already installed (if any). +to the version that is already installed (if any) and to the versions coming +from archives which in their Release files are marked as "NotAutomatic: yes" and +"ButAutomaticUpgrades: yes" like the Debian backports archive since squeeze-backports. + @@ -93,7 +127,10 @@ algorithm to set the priorities of the versions of a package. Assign: If the target release has not been specified then APT simply assigns priority 100 to all installed package versions and priority 500 to all -uninstalled package versions. +uninstalled package versions, except versions coming from archives which +in their Release files are marked as "NotAutomatic: yes" - +these versions get the priority 1 or priority 100 if it is additionally marked +as "ButAutomaticUpgrades: yes". APT then applies the following rules, listed in order of precedence, to determine which version of a package to install. @@ -144,14 +181,14 @@ and a general form. The specific form assigns a priority (a "Pin-Priority") to one or more -specified packages and specified version or version range. For example, +specified packages with a specified version or version range. For example, the following record assigns a high priority to all versions of -the perl package whose version number begins with "5.8". +the perl package whose version number begins with "&good-perl;". Multiple packages can be separated by spaces. Package: perl -Pin: version 5.8* +Pin: version &good-perl;* Pin-Priority: 1001 @@ -172,8 +209,15 @@ Pin: origin "" Pin-Priority: 999 -A note of caution: the keyword used here is "origin". -This should not be confused with the Origin of a distribution as +A note of caution: the keyword used here is "origin" +which can be used to match a hostname. The following record will assign a high priority +to all versions available from the server identified by the hostname "ftp.de.debian.org" + +Package: * +Pin: origin "ftp.de.debian.org" +Pin-Priority: 999 + +This should not be confused with the Origin of a distribution as specified in a Release file. What follows the "Origin:" tag in a Release file is not an Internet address but an author or vendor name, such as "Debian" or "Ximian". @@ -184,16 +228,25 @@ belonging to any distribution whose Archive name is "unstable Package: * Pin: release a=unstable -Pin-Priority: 500 +Pin-Priority: 50 + + +The following record assigns a high priority to all package versions +belonging to any distribution whose Codename is "&testing-codename;". + + +Package: * +Pin: release n=&testing-codename; +Pin-Priority: 900 The following record assigns a high priority to all package versions belonging to any release whose Archive name is "stable" -and whose release Version number is "3.0". +and whose release Version number is "&stable-version;". Package: * -Pin: release a=stable, v=3.0 +Pin: release a=stable, v=&stable-version; Pin-Priority: 500 @@ -202,6 +255,50 @@ Pin-Priority: 500 +Regular expressions and &glob; syntax + +APT also supports pinning by &glob; expressions, and regular +expressions surrounded by slashes. For example, the following +example assigns the priority 500 to all packages from +experimental where the name starts with gnome (as a &glob;-like +expression) or contains the word kde (as a POSIX extended regular +expression surrounded by slashes). + + + +Package: gnome* /kde/ +Pin: release n=experimental +Pin-Priority: 500 + + + +The rule for those expressions is that they can occur anywhere +where a string can occur. Thus, the following pin assigns the +priority 990 to all packages from a release starting with &ubuntu-codename;. + + + +Package: * +Pin: release n=&ubuntu-codename;* +Pin-Priority: 990 + + + +If a regular expression occurs in a Package field, +the behavior is the same as if this regular expression were replaced +with a list of all package names it matches. It is undecided whether +this will change in the future; thus you should always list wild-card +pins first, so later specific pins override it. + +The pattern "*" in a Package field is not considered +a &glob; expression in itself. + + + + + + + How APT Interprets Priorities @@ -211,30 +308,30 @@ or negative integers. They are interpreted as follows (roughly speaking): -P > 1000 +P >= 1000 causes a version to be installed even if this constitutes a downgrade of the package -990 < P <=1000 +990 <= P < 1000 causes a version to be installed even if it does not come from the target release, unless the installed version is more recent -500 < P <=990 +500 <= P < 990 causes a version to be installed unless there is a version available belonging to the target release or the installed version is more recent -100 < P <=500 +100 <= P < 500 causes a version to be installed unless there is a version available belonging to some other distribution or the installed version is more recent -0 < P <=100 +0 < P < 100 causes a version to be installed only if there is no installed version of the package @@ -256,7 +353,7 @@ records presented earlier: Package: perl -Pin: version 5.8* +Pin: version &good-perl;* Pin-Priority: 1001 Package: * @@ -272,8 +369,8 @@ Pin-Priority: 50 The most recent available version of the perl package will be installed, so long as that version's version number begins -with "5.8". If any 5.8* version of perl is -available and the installed version is 5.9*, then perl will be +with "&good-perl;". If any &good-perl;* version of perl is +available and the installed version is &bad-perl;*, then perl will be downgraded. A version of any package other than perl that is available from the local system has priority over other versions, @@ -316,7 +413,7 @@ APT priorities: The Release file is normally found in the directory .../dists/dist-name: for example, .../dists/stable/Release, -or .../dists/woody/Release. +or .../dists/&stable-codename;/Release. It consists of a single multi-line record which applies to all of the packages in the directory tree below its parent. Unlike the Packages file, nearly all of the lines in a Release @@ -324,10 +421,11 @@ file are relevant for setting APT priorities: -the Archive: line +the Archive: or Suite: line names the archive to which all the packages in the directory tree belong. For example, the line -"Archive: stable" +"Archive: stable" or +"Suite: stable" specifies that all of the packages in the directory tree below the parent of the Release file are in a stable archive. Specifying this value in the APT preferences file @@ -339,20 +437,36 @@ Pin: release a=stable + +the Codename: line +names the codename to which all the packages +in the directory tree belong. For example, the line +"Codename: &testing-codename;" +specifies that all of the packages in the directory +tree below the parent of the Release file belong to a version named +&testing-codename;. Specifying this value in the APT preferences file +would require the line: + + +Pin: release n=&testing-codename; + + + + the Version: line names the release version. For example, the -packages in the tree might belong to Debian GNU/Linux release -version 3.0. Note that there is normally no version number for the +packages in the tree might belong to Debian release +version &stable-version;. Note that there is normally no version number for the testing and unstable distributions because they have not been released yet. Specifying this in the APT preferences file would require one of the following lines. -Pin: release v=3.0 -Pin: release a=stable, v=3.0 -Pin: release 3.0 +Pin: release v=&stable-version; +Pin: release a=stable, v=&stable-version; +Pin: release &stable-version; @@ -420,10 +534,6 @@ distribution. Each record in the APT preferences file can optionally begin with one or more lines beginning with the word Explanation:. This provides a place for comments. - -The Pin-Priority: line in each APT preferences record is -optional. If omitted, APT assigs a priority of 1 less than the last value -specified on a line beginning with Pin-Priority: release .... @@ -519,10 +629,74 @@ version. apt-get install package/unstable + + + + +Tracking the evolution of a codename release + +The following APT preferences file will cause APT to assign a +priority higher than the default (500) to all package versions belonging +to a specified codename of a distribution and a prohibitively low priority to +package versions belonging to other Debian distributions, +codenames and archives. +Note that with this APT preference APT will follow the migration of a release +from the archive testing to stable and +later oldstable. If you want to follow for example the progress +in testing notwithstanding the codename changes you should use +the example configurations above. + +Explanation: Uninstall or do not install any Debian-originated package versions +Explanation: other than those in the distribution codenamed with &testing-codename; or sid +Package: * +Pin: release n=&testing-codename; +Pin-Priority: 900 + +Explanation: Debian unstable is always codenamed with sid +Package: * +Pin: release n=sid +Pin-Priority: 800 + +Package: * +Pin: release o=Debian +Pin-Priority: -10 + + + +With a suitable &sources-list; file and the above preferences file, +any of the following commands will cause APT to upgrade to the +latest version(s) in the release codenamed with &testing-codename;. + + +apt-get install package-name +apt-get upgrade +apt-get dist-upgrade + + + +The following command will cause APT to upgrade the specified +package to the latest version from the sid distribution. +Thereafter, apt-get upgrade will upgrade +the package to the most recent &testing-codename; version if that is +more recent than the installed version, otherwise, to the most recent +sid version if that is more recent than the installed +version. + + +apt-get install package/sid + + + +Files + + &file-preferences; + + + See Also &apt-get; &apt-cache; &apt-conf; &sources-list; @@ -532,4 +706,3 @@ apt-get install package/unstable &manbugs; -