Provided by: apt_0.8.3ubuntu7_i386 bug

NAME

       apt_preferences - APT

       APT /etc/apt/preferences /etc/apt/preferences.d/

       sources.list(5)  (stable testing )  APT apt-get APT APT

       sources.list(5) apt-get sources.list(5) APT

       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 questioning the preferences so wrong settings will
       therefore lead to uninstallable packages or wrong decisions while
       upgrading packages. Even more problems will arise if multiply
       distribution releases are mixed without a good understanding of the
       following paragraphs. Packages included in a specific release aren't
       tested in and therefore doesn't always work as expected in older or
       newer releases or together with other packages from different releases.
       You have been warned.

       /etc/apt/preferences.d "pref"  (-) (_) (.)

   APT
        /etc/apt/preferences pin

           apt-get install -t testing some-package

           APT::Default-Release "stable";

       APT .PP priority 1
           to the versions coming from archives which in their Release files
           are marked as "NotAutomatic: yes" like the debian experimental
           archive.

       priority 100
           ()

       priority 500

       priority 990

       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, expect versions coming from archives
       which in their Release files are marked as "NotAutomatic: yes" - these
       versions get the priority 1.

       APT

       o    1000 (APT  1000 )

       o

       o    ()

       o    --reinstall

        ( 100) sources.list(5)  ( 500  990) apt-get install some-package
       apt-get upgrade

        apt-get install some-package apt-get upgrade

        apt-get install some-package apt-get upgrade

   APT
       APT

       o    ("Pin-Priority")  () "5.8" perl

               Package: perl
               Pin: version 5.8*
               Pin-Priority: 1001

       o    (Release ) FQDN

           APT

               Package: *
               Pin: origin ""
               Pin-Priority: 999

           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".

            "unstable"

               Package: *
               Pin: release a=unstable
               Pin-Priority: 50

           The following record assigns a high priority to all package
           versions belonging to any distribution whose Codename is "squeeze".

               Package: *
               Pin: release n=squeeze
               Pin-Priority: 900

            "stable"  "3.0"

               Package: *
               Pin: release a=stable, v=3.0
               Pin-Priority: 500

   APT
       APT  (P)  () .PP P > 1000

       990 < P <=1000

       500 < P <=990

       100 < P <=500

       0 < P <=100

       P < 0

       APT

           Package: perl
           Pin: version 5.8*
           Pin-Priority: 1001

           Package: *
           Pin: origin ""
           Pin-Priority: 999

           Package: *
           Pin: release unstable
           Pin-Priority: 50

       o    "5.8" perl  5.8*  5.9* perl

       o   perl  ()

       o    sources.list(5) unstable

       sources.list(5) Packages Release

       Packages .../dists/dist-name/component/arch
       .../dists/stable/main/binary-i386/Packages APT  2 .PP Package:

       Version:

       The Release file is normally found in the directory
       .../dists/dist-name: for example, .../dists/stable/Release, or
       .../dists/lenny/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
       file are relevant for setting APT priorities:

       Archive:  Suite:
           "Archive: stable"  "Suite: stable" Release stable APT

               Pin: release a=stable

       Codename:
           names the codename to which all the packages in the directory tree
           belong. For example, the line "Codename: squeeze" specifies that
           all of the packages in the directory tree below the parent of the
           Release file belong to a version named squeeze. Specifying this
           value in the APT preferences file would require the line:

               Pin: release n=squeeze

       Version:
           GNU/Linux  3.0 testing unstable APT

               Pin: release v=3.0
               Pin: release a=stable, v=3.0
               Pin: release 3.0

       Component:
           Release "Component: main" main  (Debian ) APT

               Pin: release c=main

       Origin:
           Release Debian APT

               Pin: release o=Debian

       Label:
           Release Debian APT

               Pin: release l=Debian

       sources.list(5) Packages Release /var/lib/apt/lists apt.conf
       Dir::State::Lists
       debian.lcs.mit.edu_debian_dists_unstable_contrib_binary-i386_Release
       debian.lcs.mit.edu unstable contrib binary-i386 Release

   APT
       APT Explanation:

        APT stable  (500) Debian

           Explanation: Uninstall or do not install any Debian-originated
           Explanation: package versions other than those in the stable distro
           Package: *
           Pin: release a=stable
           Pin-Priority: 900

           Package: *
           Pin: release o=Debian
           Pin-Priority: -10

        sources.list(5) stable

           apt-get install package-name
           apt-get upgrade
           apt-get dist-upgrade

        testing

           apt-get install package/testing

        APT testing unstable Debian

           Package: *
           Pin: release a=testing
           Pin-Priority: 900

           Package: *
           Pin: release a=unstable
           Pin-Priority: 800

           Package: *
           Pin: release o=Debian
           Pin-Priority: -10

        sources.list(5) testing

           apt-get install package-name
           apt-get upgrade
           apt-get dist-upgrade

        unstable apt-get upgrade testing testing unstable unstable

           apt-get install package/unstable

        APT  (500) Debian  APT APT testing stable oldstable testing

           Explanation: Uninstall or do not install any Debian-originated package versions
           Explanation: other than those in the distribution codenamed with squeeze or sid
           Package: *
           Pin: release n=squeeze
           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

        sources.list(5) squeeze

           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 squeeze 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

       /etc/apt/preferences
             "pinning"    - Dir::Etc::Preferences

       /etc/apt/preferences.d/
             - Dir::Etc::PreferencesParts

       apt-get(8) apt-cache(8) apt.conf(5) sources.list(5)

       APT [1]  APT /usr/share/doc/debian/bug-reporting.txt reportbug(1)

        nabetaro@debian.or.jp (2003-2006,2009-2010), Debian JP Documentation
       ML debian-doc@debian.or.jp

AUTHOR

       APT

NOTES

        1. APT
           http://bugs.debian.org/src:apt