.. -*- coding: utf-8; -*-

======

 Apt.

======

.. contents::

   :local:

See man sources.list(5), apt.conf(5), apt_preferences(5).

``/etc/apt/preferences``::

  Package: *

  Pin: release a=stable

  Pin-Priority: 800

  Package: *

  Pin: release a=testing

  Pin-Priority: 900

  Package: *

  Pin: release a=unstable

  Pin-Priority: 700

  Package: *

  Pin: release a=experimental

  Pin-Priority: 600

Example that prevent installing ``*systemd*`` packages (priority strictly below

``0`` forbid package to be installed)::

  Package: systemd

  Pin: origin ""

  Pin-Priority: -1

  Package: *systemd*

  Pin: origin ""

  Pin-Priority: -1

Example that avoid installing packages from different distribution (priority

strictly below ``100`` cause a version to be installed only if there is no

installed version of the package), you should keep main distribution priority

above foreign distro priority::

  Package: *

  Pin: release a=testing

  Pin-Priority: 990

  Package: *

  Pin: release o=Kali

  Pin-Priority: 50

To discover package priority::

  bash# apt-cache madison emacs24

     emacs24 |   24.5+1-3 | http://ftp.us.debian.org/debian/ testing/main amd64 Packages

     emacs24 |   24.4+1-5 | http://http.kali.org/kali/ kali-current/main amd64 Packages

     emacs24 |   24.5+1-3 | http://ftp.us.debian.org/debian/ testing/main Sources

  bash# apt-cache policy emacs24

  emacs24:

    Installed: 24.5+1-3

    Candidate: 24.5+1-3

    Version table:

   *** 24.5+1-3 0

          990 http://ftp.us.debian.org/debian/ testing/main amd64 Packages

          100 /var/lib/dpkg/status

       24.4+1-5 0

           50 http://http.kali.org/kali/ kali-current/main amd64 Packages

  bash# aptitude versions emacs24

  Package emacs24:

  p   24.4+1-5                                      kali-current              50

  i   24.5+1-3                                      testing                   990

Setup backport.

===============

Main backports archive located at http://www.backports.org.

To get packeges gpg sign key::

  $ su

  ...

  $ wget -O - http://backports.org/debian/archive.key | apt-key add -

  $ ^D

Write where packeges places::

  $ cat /etc/apt/sources.list

  deb http://www.backports.org/debian/ etch-backports main contrib non-free

Importing package signing key.

==============================

Usualy you can safely update keyring via ``debian-keyring`` package because it

is signed by prevoius keyring::

  $ sudo apt-get install debian-keyring

Defferent 3rd party provide keys for download. If you trust key (or get it in a

trusted way) it is easy to import it::

  $ sudo apt-key add $FILE.pgp

Another way to resolve warning::

  $ sudo apt-get update

  ...

  W: There is no public key available for the following key IDs:

  9AA38DCD55BE302B

  W: GPG error: http://http.us.debian.org etch Release: The following signatures

  couldn't be verified because the public key is not available: NO_PUBKEY

  9AA38DCD55BE302B

  ...

is to use key servers directly::

  $ gpg --keyserver pgp.mit.edu --recv-key 9AA38DCD55BE302B \

  --keyserver-options http-proxy=http://user:pass@192.168.1.1:3128

  gpg: requesting key 55BE302B from hkp server pgp.mit.edu

  gpg: key 55BE302B: public key "Debian Archive Automatic Signing Key (5.0/lenny) <ftpmaster@debian.org>" imported

  gpg: no ultimately trusted keys found

  gpg: Total number processed: 1

  gpg:               imported: 1  (RSA: 1)

  $ gpg --export 9AA38DCD55BE302B | sudo apt-key add -

  OK

Install build dependency for package.

=====================================

::

  $ apt-get install build-essential    # install dev LIBC and GCC C/C++

  $ sudo apt-get build-dep $package

If all you want is checking what packages are needed to build a given package::

  $ apt-cache showsrc $package

or check 'Build-Depends' attribute in::

  $ apt-cache show $package

Delete config file for removed packages.

========================================

To get list of such packages use one of::

  $ aptitude search ~c

  $ grep-status -n -sPackage -FStatus config-files

To remove them::

  $ aptitude purge ~c

Delete obsolete packages.

=========================

To get list of such packages use::

  $ aptitude search ~o

To remove them::

  $ aptitude purge ~o

To remove packages that were automatically installed to satisfy dependencies and

are now no longer needed::

  $ sudo apt-get autoremove

Clean up packages cache.

========================

Remove everything from ``/var/cache/apt/archives/`` and

``/var/cache/apt/archives/partial/``::

  $ sudo apt-get clean

Removes package files that can no longer be downloaded, and are largely

useless::

  $ sudo apt-get autoclean

Check package files for modification.

=====================================

::

  $ sudo debsums --changed

Search for packages.

====================

::

  $ aptitude search '?tag(works-with::logfile)'

Show dependency graph.

======================

::

  $ apt-cache dotty $PKG | dot -Tsvg >$PKG.svg && see $PKG.svg

  $ sudo apt-get install debtree

  $ debtree $PKG | dot -Tsvg >$PKG.svg && see $PKG.svg

  $ sudo apt-get install apt-rdepends

  $ apt-rdepends $PKG

  $ apt-rdepends -r $PKG

  $ apt-rdepends -d $PKG | dot -Tsvg >$PKG.svg && see $PKG.svg

  $ apt-rdepends -d -r $PKG | dot -Tsvg >$PKG.svg && see $PKG.svg