Table of Contents
apt-get
/ apt-cache
vs. aptitude
testing
with some packages from unstable
unstable
with some packages from experimental
Note | |
---|---|
This chapter is written assuming the latest stable release is codename: |
Debian is a volunteer organization which builds consistent distributions of pre-compiled binary packages of free software and distributes them from its archive.
The Debian archive is offered by many remote mirror sites for access through HTTP and FTP methods. It is also available as CD-ROM/DVD.
The Debian package management system, when used properly, offers the user to install consistent sets of binary packages to the system from the archive. Currently, there are 37617 packages available for the amd64 architecture.
The Debian package management system has a rich history and many choices for the front end user program and back end archive access method to be used. Currently, we recommend the following.
apt-get(8) for all commandline operations, including package installation and removal, and dist-upgrades.
aptitude(8) for an interactive text interface to manage the installed packages and to search the available packages.
update-manager(8) for keeping your system up-to-date if you're running the default GNOME desktop.
Table 2.1. List of Debian package management tools
package | popcon | size | description |
---|---|---|---|
apt
|
http://qa.debian.org/popcon.php?package=apt | 3072 |
Advanced Packaging Tool (APT), front-end for dpkg providing "http ", "ftp ", and "file " archive access methods (apt-get /apt-cache commands included)
|
aptitude
|
http://qa.debian.org/popcon.php?package=aptitude | 12575 | interactive terminal-based package manager with aptitude(8) |
update-manager-gnome
|
http://qa.debian.org/popcon.php?package=update-manager-gnome | 1266 | GNOME application that manages software updates with update-manager(8) |
tasksel
|
http://qa.debian.org/popcon.php?package=tasksel | 188 | tool for selecting tasks for installation on Debian system (front-end for APT) |
unattended-upgrades
|
http://qa.debian.org/popcon.php?package=unattended-upgrades | 252 | enhancement package for APT to enable automatic installation of security upgrades |
dselect
|
http://qa.debian.org/popcon.php?package=dselect | 2376 | terminal-based package manager (previous standard, front-end for APT and other old access methods) |
dpkg
|
http://qa.debian.org/popcon.php?package=dpkg | 5824 | package management system for Debian |
synaptic
|
http://qa.debian.org/popcon.php?package=synaptic | 7620 | graphical package manager (GNOME front-end for APT) |
apt-utils
|
http://qa.debian.org/popcon.php?package=apt-utils | 1275 | APT utility programs: apt-extracttemplates(1), apt-ftparchive(1), and apt-sortpkgs(1) |
apt-listchanges
|
http://qa.debian.org/popcon.php?package=apt-listchanges | 202 | package change history notification tool |
apt-listbugs
|
http://qa.debian.org/popcon.php?package=apt-listbugs | 370 | lists critical bugs before each APT installation |
apt-file
|
http://qa.debian.org/popcon.php?package=apt-file | 120 | APT package searching utility — command-line interface |
apt-rdepends
|
http://qa.debian.org/popcon.php?package=apt-rdepends | 80 | recursively lists package dependencies |
Here are some key points for package configuration on the Debian system.
The manual configuration by the system administrator is respected. In other words, the package configuration system makes no intrusive configuration for the sake of convenience.
Each package comes with its own configuration script with standardized user interface called debconf(7) to help initial installation process of the package.
Debian Developers try their best to make your upgrade experience flawless with package configuration scripts.
Full functionalities of packaged software are available to the system administrator. But ones with security risks are disabled in the default installation.
If you manually activate a service with some security risks, you are responsible for the risk containment.
Esoteric configuration may be manually enabled by the system administrator. This may creates interference with popular generic helper programs for the system configuration.
Warning | |
---|---|
Do not install packages from random mixture of suites. It probably breaks the package consistency which requires deep system management knowledge, such as compiler ABI, library version, interpreter features, etc. |
The newbie Debian system administrator should stay with the stable
release of Debian while applying only security updates. I mean that some of the following valid actions are better avoided, as a precaution, until you understand the Debian system very well. Here are some reminders.
Do not include testing
or unstable
in "/etc/apt/sources.list
".
Do not mix standard Debian with other non-Debian archives such as Ubuntu in "/etc/apt/sources.list
".
Do not create "/etc/apt/preferences
".
Do not change default behavior of package management tools through configuration files without knowing their full impacts.
Do not install random packages by "dpkg -i <random_package>
".
Do not ever install random packages by "dpkg --force-all -i <random_package>
".
Do not erase or alter files in "/var/lib/dpkg/
".
Do not overwrite system files by installing software programs directly compiled from source.
Install them into "/usr/local
" or "/opt
", if needed.
The non-compatible effects caused by above actions to the Debian package management system may leave your system unusable.
The serious Debian system administrator who runs mission critical servers, should use extra precautions.
Do not install any packages including security updates from Debian without thoroughly testing them with your particular configuration under safe conditions.
You as the system administrator are responsible for your system in the end.
The long stability history of Debian system is no guarantee by itself.
Despite my warnings above, I know many readers of this document wish to run the testing
or unstable
suites of Debian as their main system for self-administered Desktop environments. This is because they work very well, are updated frequently, and offer the latest features.
Caution | |
---|---|
For your production server, the |
It takes no more than simply setting the distribution string in the "/etc/apt/sources.list
" to the suite name: "testing
" or "unstable
"; or the codename: "wheezy
" or "sid
". This makes you live the life of eternal upgrades.
The use of testing
or unstable
is a lot of fun but comes with some risks. Even though the unstable
suite of Debian system looks very stable for most of the times, there have been some package problems on the testing
and unstable
suite of Debian system and a few of them were not so trivial to resolve. It may be quite painful for you. Sometimes, you may have a broken package or missing functionality for a few weeks.
Here are some ideas to ensure quick and easy recovery from bugs in Debian packages.
Make the system dual bootable by installing the stable
suite of Debian system to another partition
Make the installation CD handy for the rescue boot
Consider installing apt-listbugs
to check the Debian Bug Tracking System (BTS) information before the upgrade
Learn the package system infrastructure enough to work around the problem
Create a chroot or similar environment and run the latest system in it in advance (see Section 9.8, “Virtualized system”)
(If you can not do any one of these precautionary actions, you are probably not ready for the testing
and unstable
suites.)
Enlightenment with the following saves a person from the eternal karmic struggle of upgrade hell and let him reach Debian nirvana.
Let's look into the Debian archive from a system user's perspective.
Tip | |
---|---|
Official policy of the Debian archive is defined at Debian Policy Manual, Chapter 2 - The Debian Archive. |
For the typical HTTP access, the archive is specified in the "/etc/apt/sources.list
" file as the following, e.g. for the current stable
= squeeze
system.
deb http://ftp.XX.debian.org/debian/ squeeze main contrib non-free deb-src http://ftp.XX.debian.org/debian/ squeeze main contrib non-free deb http://security.debian.org/ squeeze/updates main contrib deb-src http://security.debian.org/ squeeze/updates main contrib
Please note "ftp.XX.debian.org
" must be replaced with appropriate mirror site URL for your location, for USA "ftp.us.debian.org
", which can be found in the list of Debian worldwide mirror sites. The status of these servers can be checked at Debian Mirror Checker site.
Here, I tend to use codename "squeeze
" instead of suite name "stable
" to avoid surprises when the next stable
is released.
The meaning of "/etc/apt/sources.list
" is described in sources.list(5) and key points are followings.
The "deb
" line defines for the binary packages.
The "deb-src
" line defines for the source packages.
The 1st argument is the root URL of the Debian archive.
The 2nd argument is the distribution name: either the suite name or the codename.
The 3rd and following arguments are the list of valid archive area names of the Debian archive.
The "deb-src
" lines can safely be omitted (or commented out by placing "#" at the start of the line) if it is just for aptitude
which does not access source related meta data. It speeds up the updates of the archive meta data. The URL can be "http://
", "ftp://
", "file://
", ….
Tip | |
---|---|
If " |
Here is the list of URL of the Debian archive sites and suite name or codename used in the configuration file.
Table 2.2. List of Debian archive sites
archive URL | suite name (codename) | purpose |
---|---|---|
http://ftp.XX.debian.org/debian/ |
stable (squeeze )
|
stable (squeeze) release |
http://ftp.XX.debian.org/debian/ |
testing (wheezy )
|
testing (wheezy) release |
http://ftp.XX.debian.org/debian/ |
unstable (sid )
|
unstable (sid) release |
http://ftp.XX.debian.org/debian/ |
experimental
|
experimental pre-release (optional, only for developer) |
http://ftp.XX.debian.org/debian/ |
stable-proposed-updates
|
Updates for the next stable point release (optional) |
http://security.debian.org/ |
stable/updates
|
security updates for stable release (important) |
http://security.debian.org/ |
testing/updates
|
security updates for testing release (important) |
http://ftp.XX.debian.org/debian/ |
squeeze-updates
|
compatible updates for spam filter, IM clients, etc. for squeeze |
http://backports.debian.org/debian-backports/ |
squeeze-backports
|
newer backported packages for squeeze (optional) |
Caution | |
---|---|
Only pure |
Caution | |
---|---|
You should basically list only one of |
Tip | |
---|---|
For the Debian system with the |
Note | |
---|---|
The security bugs for the |
Table 2.3. List of Debian archive area
area | number of packages | criteria of package component |
---|---|---|
main
|
36909 |
DFSG compliant and no dependency to non-free
|
contrib
|
231 |
DFSG compliant but having dependency to non-free
|
non-free
|
477 | not DFSG compliant |
Here the number of packages in the above is for the amd64 architecture. Strictly speaking, only the main
area archive shall be considered as the Debian system.
The Debian archive organization can be studied best by pointing your browser to the each archive URL appended with dists
or pool
.
The distribution is referred by two ways, the suite or codename. The word distribution is alternatively used as the synonym to the suite in many documentations. The relationship between the suite and the codename can be summarized as the following.
Table 2.4. The relationship between suite and codename
Timing |
suite = stable
|
suite = testing
|
suite = unstable
|
---|---|---|---|
after the squeeze release
|
codename = squeeze
|
codename = wheezy
|
codename = sid
|
after the wheezy release
|
codename = wheezy
|
codename = wheezy+1
|
codename = sid
|
The history of codenames are described in Debian FAQ: 6.3.1 Which other codenames have been used in the past?
In the stricter Debian archive terminology, the word "section" is specifically used for the categorization of packages by the application area. (Although, the word "main section" may sometimes be used to describe the Debian archive area named as "main".)
Every time a new upload is done by the Debian developer (DD) to the unstable
archive (via incoming processing), DD is required to ensure uploaded packages to be compatible with the latest set of packages in the latest unstable
archive.
If DD breaks this compatibility intentionally for important library upgrade etc, there is usually announcement to the debian-devel mailing list etc.
Before a set of packages are moved by the Debian archive maintenance script from the unstable
archive to the testing
archive, the archive maintenance script not only checks the maturity (about 10 days old) and the status of the RC bug reports for the packages but also tries to ensure them to be compatible with the latest set of packages in the testing
archive. This process makes the testing
archive very current and usable.
Through the gradual archive freeze process led by the release team, the testing
archive is matured to make it completely consistent and bug free with some manual interventions. Then the new stable
release is created by assigning the codename for the old testing
archive to the new stable
archive and creating the new codename for the new testing
archive. The initial contents of the new testing
archive is exactly the same as that of the newly released stable
archive.
Both the unstable
and the testing
archives may suffer temporary glitches due to several factors.
Broken package upload to the archive (mostly for unstable
)
Delay of accepting the new packages to the archive (mostly for unstable
)
Archive synchronization timing issue (both for testing
and unstable
)
Manual intervention to the archive such as package removal (more for testing
) etc.
So if you ever decide to use these archives, you should be able to fix or work around these kinds of glitches.
Caution | |
---|---|
For about few months after a new |
Tip | |
---|---|
When tracking the |
See Debian Policy Manual for archive definitions.
The Debian system offers a consistent set of binary packages through its versioned binary dependency declaration mechanism in the control file fields. Here is a bit over simplified definition for them.
"Depends"
This declares an absolute dependency and all of the packages listed in this field must be installed at the same time or in advance.
"Pre-Depends"
This is like Depends, except that it requires completed installation of the listed packages in advance.
"Recommends"
This declares a strong, but not absolute, dependency. Most users would not want the package unless all of the packages listed in this field are installed.
"Suggests"
This declares a weak dependency. Many users of this package may benefit from installing packages listed in this field but can have reasonable functions without them.
"Enhances"
This declares a week dependency like Suggests but works in the opposite direction.
"Breaks"
This declares a package incompatibility usually with some version specification. Generally the resolution is to upgrade all of the packages listed in this field.
"Conflicts"
This declares an absolute incompatibility. All of the packages listed in this field must be removed to install this package.
"Replaces"
This is declared when files installed by this package replace files in the listed packages.
"Provides"
This is declared when this package provide all of the files and functionality in the listed packages.
Note | |
---|---|
Please note that defining, "Provides", "Conflicts" and "Replaces" simultaneously to an virtual package is the sane configuration. This ensures that only one real package providing this virtual package can be installed at any one time. |
The official definition including source dependency can be found in the Policy Manual: Chapter 7 - Declaring relationships between packages.
Here is a summary of the simplified event flow of the package management by APT.
Update ("aptitude update
" or "apt-get update
"):
Fetch archive metadata from remote archive
Reconstruct and update local metadata for use by APT
Upgrade ("aptitude safe-upgrade
" and "aptitude full-upgrade
", or "apt-get upgrade
" and "apt-get dist-upgrade
"):
Chose candidate version which is usually the latest available version for all installed packages (see Section 2.7.3, “Tweaking candidate version” for exception)
Make package dependency resolution
Fetch selected binary packages from remote archive if candidate version is different from installed version
Unpack fetched binary packages
Run preinst script
Install binary files
Run postinst script
Install ("aptitude install …
" or "apt-get install …
"):
Chose packages listed on the command line
Make package dependency resolution
Fetch selected binary packages from remote archive
Unpack fetched binary packages
Run preinst script
Install binary files
Run postinst script
Remove ("aptitude remove …
" or "apt-get remove …
"):
Chose packages listed on the command line
Make package dependency resolution
Run prerm script
Remove installed files except configuration files
Run postrm script
Purge ("aptitude purge …
" or "apt-get purge …
"):
Chose packages listed on the command line
Make package dependency resolution
Run prerm script
Remove installed files including configuration files
Run postrm script
Here, I intentionally skipped technical details for the sake of big picture.
You should read the fine official documentation. The first document to read is the Debian specific "/usr/share/doc/<package_name>/README.Debian
". Other documentation in "/usr/share/doc/<package_name>/
" should be consulted too. If you set shell as Section 1.4.2, “Customizing bash”, type the following.
$ cd <package_name> $ pager README.Debian $ mc
You may need to install the corresponding documentation package named with "-doc
" suffix for detailed information.
If you are experiencing problems with a specific package, make sure to check out the Debian bug tracking system (BTS) sites, first.
Table 2.5. List of key web site to resolving problems with a specific package
web site | command |
---|---|
Home page of the Debian bug tracking system (BTS) |
sensible-browser "http://bugs.debian.org/"
|
The bug report of a known package name |
sensible-browser "http://bugs.debian.org/<package_name>"
|
The bug report of known bug number |
sensible-browser "http://bugs.debian.org/<bug_number>"
|
Search Google with search words including "site:debian.org
", "site:wiki.debian.org
", "site:lists.debian.org
", etc.
When you file a bug report, please use reportbug(1) command.
Basic package management operations on the Debian system can be performed by any package management tools available on the Debian system. Here, we explain basic package management tools: apt-get
/ apt-cache
and aptitude
.
For the package management operation which involves package installation or updates package metadata, you need to have root privilege.
The apt-get
and apt-cache
commands are the most basic package management tool.
apt-get
and apt-cache
offer only the commandline user interface.
apt-get
is most suitable for the major system upgrade between releases, etc.
apt-get
offers a robust and stable package resolver which uses the common package state data.
apt-get
is less demanding on hardware resources. It consumes less memory and runs faster.
apt-get
has been updated to support autoinstall and autoremove of recommended packages.
apt-get
has been updated to support logging of package activities.
apt-cache
offers a standard regex based search on the package name and description.
apt-get
and apt-cache
can manage multiple versions of packages using /etc/apt/preferences
but it is quite cumbersome.
The aptitude
command is the most versatile package management tool.
aptitude
offers the fullscreen interactive text user interface.
aptitude
offers the commandline user interface, too.
aptitude
is most suitable for the daily interactive package management such as inspecting installed packages and searching available packages.
aptitude
is more demanding on hardware resources. It consumes more memory and runs slower.
aptitude
offers an enhanced package resolver which also uses an extra package state data used only by aptitude
.
aptitude
supports autoinstall and autoremove of recommended packages.
aptitude
supports logging of package activities.
aptitude
offers an enhanced regex based search on all of the package metadata.
aptitude
can manage multiple versions of packages without using /etc/apt/preferences
and it is quite intuitive.
Note | |
---|---|
Although the |
Here are basic package management operations with the commandline using aptitude(8) and apt-get(8) /apt-cache(8).
Table 2.6. Basic package management operations with the commandline using aptitude(8) and apt-get(8) /apt-cache(8)
aptitude syntax
|
apt-get /apt-cache syntax
|
description |
---|---|---|
aptitude update
|
apt-get update
|
update package archive metadata |
aptitude install foo
|
apt-get install foo
|
install candidate version of "foo " package with its dependencies
|
aptitude safe-upgrade
|
apt-get upgrade
|
install candidate version of installed packages without removing any other packages |
aptitude full-upgrade
|
apt-get dist-upgrade <package>
|
install candidate version of installed packages while removing other packages if needed |
aptitude remove foo
|
apt-get remove foo
|
remove "foo " package while leaving its configuration files
|
N/A |
apt-get autoremove
|
remove auto-installed packages which is no longer required |
aptitude purge foo
|
apt-get purge foo
|
purge "foo " package with its configuration files
|
aptitude clean
|
apt-get clean
|
clear out the local repository of retrieved package files completely |
aptitude autoclean
|
apt-get autoclean
|
clear out the local repository of retrieved package files for outdated packages |
aptitude show foo
|
apt-cache show <package>
|
display detailed information about "foo " package
|
aptitude search <regex>
|
apt-cache search <regex>
|
search packages which match <regex> |
aptitude why <regex>
|
N/A | explain the reason why <regex> matching packages should be installed |
aptitude why-not <regex>
|
N/A | explain the reason why <regex> matching packages can not be installed |
Note | |
---|---|
Since |
The difference between "safe-upgrade
"/"upgrade
" and "full-upgrade
"/"dist-upgrade
" only appears when new versions of packages stand in different dependency relationships from old versions of those packages. The "aptitude safe-upgrade
" command does not install new packages nor remove installed packages.
The "aptitude why <regex>
" can list more information by "aptitude -v why <regex>
". Similar information can be obtained by "apt-cache rdepends <package>
".
When aptitude
command is started in the commandline mode and faces some issues such as package conflicts, you can switch to the full screen interactive mode by pressing "e
"-key later at the prompt.
You may provide command options right after "aptitude
".
Table 2.7. Notable command options for aptitude(8)
command option | description |
---|---|
-s
|
simulate the result of the command |
-d
|
download only but no install/upgrade |
-D
|
show brief explanations before the automatic installations and removals |
See aptitude(8) and "aptitude user's manual" at "/usr/share/doc/aptitude/README
" for more.
Tip | |
---|---|
The |
For the interactive package management, you start aptitude
in interactive mode from the console shell prompt as follows.
$ sudo aptitude -u Password:
This updates the local copy of the archive information and display the package list in the full screen with menu. Aptitude places its configuration at "~/.aptitude/config
".
Tip | |
---|---|
If you want to use root's configuration instead of user's one, use " |
Tip | |
---|---|
|
Notable key strokes to browse status of packages and to set "planned action" on them in this full screen mode are the following.
Table 2.8. List of key bindings for aptitude
key | key binding |
---|---|
F10 or Ctrl-t
|
menu |
?
|
display help for keystroke (more complete listing) |
F10 → Help → User's Manual
|
display User's Manual |
u
|
update package archive information |
+
|
mark the package for the upgrade or the install |
-
|
mark the package for the remove (keep configuration files) |
_
|
mark the package for the purge (remove configuration files) |
=
|
place the package on hold |
U
|
mark all upgradable packages (function as full-upgrade) |
g
|
start downloading and installing selected packages |
q
|
quit current screen and save changes |
x
|
quit current screen and discard changes |
Enter
|
view information about a package |
C
|
view a package's changelog |
l
|
change the limit for the displayed packages |
/
|
search for the first match |
\
|
repeat the last search |
The file name specification of the command line and the menu prompt after pressing "l
" and "//
" take the aptitude regex as described below. Aptitude regex can explicitly match a package name using a string started by "~n
and followed by the package name.
Tip | |
---|---|
You need to press " |
In the interactive full screen mode of aptitude(8), packages in the package list are displayed as the next example.
idA libsmbclient -2220kB 3.0.25a-1 3.0.25a-2
Here, this line means from the left as the following.
The "current state" flag (the first letter)
The "planned action" flag (the second letter)
The "automatic" flag (the third letter)
The Package name
The change in disk space usage attributed to "planned action"
The current version of the package
The candidate version of the package
Tip | |
---|---|
The full list of flags are given at the bottom of Help screen shown by pressing " |
The candidate version is chosen according to the current local preferences (see apt_preferences(5) and Section 2.7.3, “Tweaking candidate version”).
Several types of package views are available under the menu "Views
".
Table 2.9. List of views for aptitude
view | status | description of view |
---|---|---|
Package View
|
Good | see Table 2.10, “The categorization of standard package views” (default) |
Audit Recommendations
|
Good | list packages which are recommended by some installed packages but not yet installed are listed |
Flat Package List
|
Good | list packages without categorization (for use with regex) |
Debtags Browser
|
Very usable | list packages categorized according to their debtags entries |
Categorical Browser
|
Deprecated |
list packages categorized according to their category (use Debtags Browser , instead)
|
Note | |
---|---|
Please help us improving tagging packages with debtags! |
The standard "Package View
" categorizes packages somewhat like dselect
with few extra features.
Table 2.10. The categorization of standard package views
category | description of view |
---|---|
Upgradable Packages
|
list packages organized as section → area → package
|
New Packages
|
, , |
Installed Packages
|
, , |
Not Installed Packages
|
, , |
Obsolete and Locally Created Packages
|
, , |
Virtual Packages
|
list packages with the same function |
Tasks
|
list packages with different functions generally needed for a task |
Tip | |
---|---|
|
Aptitude offers several options for you to search packages using its regex formula.
Shell commandline:
"aptitude search '<aptitude_regex>'
" to list installation status, package name and short description of matching packages
"aptitude show '<package_name>'
" to list detailed description of the package
Interactive full screen mode:
"l
" to limit package view to matching packages
"/
" for search to a matching package
"\
" for backward search to a matching package
"n
" for find-next
"N
" for find-next (backward)
Tip | |
---|---|
The string for <package_name> is treated as the exact string match to the package name unless it is started explicitly with " |
The aptitude regex formula is mutt-like extended ERE (see Section 1.6.2, “Regular expressions”) and the meanings of the aptitude
specific special match rule extensions are as follows.
Table 2.11. List of the aptitude regex formula
description of the extended match rule | regex formula |
---|---|
match on package name |
~n<regex_name>
|
match on description |
~d<regex_description>
|
match on task name |
~t<regex_task>
|
match on debtag |
~G<regex_debtag>
|
match on maintainer |
~m<regex_maintainer>
|
match on package section |
~s<regex_section>
|
match on package version |
~V<regex_version>
|
match archive |
~A{sarge,etch,sid }
|
match origin |
~O{debian,… }
|
match priority |
~p{extra,important,optional,required,standard }
|
match essential packages |
~E
|
match virtual packages |
~v
|
match new packages |
~N
|
match with pending action |
~a{install,upgrade,downgrade,remove,purge,hold,keep }
|
match installed packages |
~i
|
match installed packages with A-mark (auto installed package) |
~M
|
match installed packages without A-mark (administrator selected package) |
~i!~M
|
match installed and upgradable packages |
~U
|
match removed but not purged packages |
~c
|
match removed, purged or can-be-removed packages |
~g
|
match packages with broken relation |
~b
|
match packages with broken depends/predepends/conflict |
~B<type>
|
match packages from which relation <type> is defined to <term> package |
~D[<type>:]<term>
|
match packages from which broken relation <type> is defined to <term> package |
~DB[<type>:]<term>
|
match packages to which the <term> package defines relation <type> |
~R[<type>:]<term>
|
match packages to which the <term> package defines broken relation <type> |
~RB[<type>:]<term>
|
match packages to which some other installed packages depend on |
~R~i
|
match packages to which no other installed packages depend on |
!~R~i
|
match packages to which some other installed packages depend or recommend on |
~R~i|~Rrecommends:~i
|
match <term> package with filtered version |
~S filter <term>
|
match all packages (true) |
~T
|
match no packages (false) |
~F
|
The regex part is the same ERE as the one used in typical Unix-like text tools using "^
", ".*
", "$
" etc. as in egrep(1), awk(1) and perl(1).
The relation <type> is one of (depends, predepends, recommends, suggests, conflicts, replaces, provides).
The default relation type is "depends".
Tip | |
---|---|
When <regex_pattern> is a null string, place " |
Here are some short cuts.
"~P<term>
" == "~Dprovides:<term>
"
"~C<term>
" == "~Dconflicts:<term>
"
"…~W term
" == "(…|term)
"
Users familiar with mutt
pick up quickly, as mutt was the inspiration for the expression syntax. See "SEARCHING, LIMITING, AND EXPRESSIONS" in the "User's Manual" "/usr/share/doc/aptitude/README
".
Note | |
---|---|
With the |
The selection of a package in aptitude
not only pulls in packages which are defined in its "Depends:
" list but also defined in the "Recommends:
" list if the menu "F10
→ Options → Dependency handling" is set accordingly. These auto installed packages are removed automatically if they are no longer needed under aptitude
.
Note | |
---|---|
Before the |
You can check package activity history in the log files.
Table 2.12. The log files for package activities
file | content |
---|---|
/var/log/dpkg.log
|
Log of dpkg level activity for all package activities
|
/var/log/apt/term.log
|
Log of generic APT activity |
/var/log/aptitude
|
Log of aptitude command activity
|
In reality, it is not so easy to get meaningful understanding quickly out from these logs. See Section 9.2.10, “Recording changes in configuration files” for easier way.
Here are few examples of aptitude(8) operations.
The following command lists packages with regex matching on package names.
$ aptitude search '~n(pam|nss).*ldap' p libnss-ldap - NSS module for using LDAP as a naming service p libpam-ldap - Pluggable Authentication Module allowing LDAP interfaces
This is quite handy for you to find the exact name of a package.
The regex "~dipv6
" in the "New Flat Package List" view with "l
" prompt, limits view to packages with the matching description and let you browse their information interactively.
You can purge all remaining configuration files of removed packages.
Check results of the following command.
# aptitude search '~c'
If you think listed packages are OK to be purged, execute the following command.
# aptitude purge '~c'
You may want to do the similar in the interactive mode for fine grained control.
You provide the regex "~c
" in the "New Flat Package List" view with "l
" prompt. This limits the package view only to regex matched packages, i.e., "removed but not purged". All these regex matched packages can be shown by pressing "[
" at top level headings.
Then you press "_
" at top level headings such as "Installed Packages". Only regex matched packages under the heading are marked to be purged by this. You can exclude some packages to be purged by pressing "=
" interactively for each of them.
This technique is quite handy and works for many other command keys.
Here is how I tidy auto/manual install status for packages (after using non-aptitude package installer etc.).
Start aptitude
in interactive mode as root.
Type "u
", "U
", "f
" and "g
" to update and upgrade package list and packages.
Type "l
" to enter the package display limit as "~i(~R~i|~Rrecommends:~i)
" and type "M
" over "Installed Packages
" as auto installed.
Type "l
" to enter the package display limit as "~prequired|~pimportant|~pstandard|~E
" and type "m
" over "Installed Packages
" as manual installed.
Type "l
" to enter the package display limit as "~i!~M
" and remove unused package by typing "-
" over each of them after exposing them by typing "[
" over "Installed Packages
".
Type "l
" to enter the package display limit as "~i
" and type "m
" over "Tasks
" as manual installed.
Exit aptitude
.
Start "apt-get -s autoremove|less
" as root to check what are not used.
Restart aptitude
in interactive mode and mark needed packages as "m
".
Restart "apt-get -s autoremove|less
" as root to recheck REMOVED contain only expected packages.
Start "apt-get autoremove|less
" as root to autoremove unused packages.
The "m
" action over "Tasks
" is an optional one to prevent mass package removal situation in future.
Note | |
---|---|
When moving to a new release etc, you should consider to perform a clean installation of new system even though Debian is upgradable as described below. This provides you a chance to remove garbages collected and exposes you to the best combination of latest packages. Of course, you should make a full backup of system to a safe place (see Section 10.1.6, “Backup and recovery”) before doing this. I recommend to make a dual boot configuration using different partition to have the smoothest transition. |
You can perform system wide upgrade to a newer release by changing contents of the "/etc/apt/sources.list
" file pointing to a new release and running the "apt-get update; apt-get dist-upgrade
" command.
To upgrade from stable
to testing
or unstable
, you replace "squeeze
" in the "/etc/apt/sources.list
" example of Section 2.1.4, “Debian archive basics” with "wheezy
" or "sid
".
In reality, you may face some complications due to some package transition issues, mostly due to package dependencies. The larger the difference of the upgrade, the more likely you face larger troubles. For the transition from the old stable
to the new stable
after its release, you can read its new Release Notes and follow the exact procedure described in it to minimize troubles.
When you decide to move from stable
to testing
before its formal release, there are no Release Notes to help you. The difference between stable
and testing
could have grown quite large after the previous stable
release and makes upgrade situation complicated.
You should make precautionary moves for the full upgrade while gathering latest information from mailing list and using common senses.
Read previous "Release Notes".
Backup entire system (especially data and configuration information).
Have bootable media handy for broken bootloader.
Inform users on the system well in advance.
Record upgrade activity with script(1).
Apply "unmarkauto" to required packages, e.g., "aptitude unmarkauto vim
", to prevent removal.
Minimize installed packages to reduce chance of package conflicts, e.g., remove desktop task packages.
Remove the "/etc/apt/preferences
" file (disable apt-pinning).
Try to upgrade step wise: oldstable
→ stable
→ testing
→ unstable
.
Update the "/etc/apt/sources.list
" file to point to new archive only and run "aptitude update
".
Install, optionally, new core packages first, e.g., "aptitude install perl
".
Run the "apt-get -s dist-upgrade
" command to assess impact.
Run the "apt-get dist-upgrade
" command at last.
Caution | |
---|---|
It is not wise to skip major Debian release when upgrading between |
Caution | |
---|---|
In previous "Release Notes", GCC, Linux Kernel, initrd-tools, Glibc, Perl, APT tool chain, etc. have required some special attention for system wide upgrade. |
For daily upgrade in unstable
, see Section 2.4.3, “Safeguarding for package problems”.
Here are list of other package management operations for which aptitude
is too high-level or lacks required functionalities.
Table 2.13. List of advanced package management operations
command | action |
---|---|
COLUMNS=120 dpkg -l <package_name_pattern>
|
list status of an installed package for the bug report |
dpkg -L <package_name>
|
list contents of an installed package |
dpkg -L <package_name> | egrep '/usr/share/man/man.*/.+'
|
list manpages for an installed package |
dpkg -S <file_name_pattern>
|
list installed packages which have matching file name |
apt-file search <file_name_pattern>
|
list packages in archive which have matching file name |
apt-file list <package_name_pattern>
|
list contents of matching packages in archive |
dpkg-reconfigure <package_name>
|
reconfigure the exact package |
dpkg-reconfigure -p=low <package_name>
|
reconfigure the exact package with the most detailed question |
configure-debian
|
reconfigure packages from the full screen menu |
dpkg --audit
|
audit system for partially installed packages |
dpkg --configure -a
|
configure all partially installed packages |
apt-cache policy <binary_package_name>
|
show available version, priority, and archive information of a binary package |
apt-cache madison <package_name>
|
show available version, archive information of a package |
apt-cache showsrc <binary_package_name>
|
show source package information of a binary package |
apt-get build-dep <package_name>
|
install required packages to build package |
aptitude build-dep <package_name>
|
install required packages to build package |
apt-get source <package_name>
|
download a source (from standard archive) |
dget <URL for dsc file>
|
download a source packages (from other archive) |
dpkg-source -x <package_name>_<version>-<debian_version>.dsc
|
build a source tree from a set of source packages ("*.orig.tar.gz " and "*.debian.tar.gz "/"*.diff.gz ")
|
debuild binary
|
build package(s) from a local source tree |
make-kpkg kernel_image
|
build a kernel package from a kernel source tree |
make-kpkg --initrd kernel_image
|
build a kernel package from a kernel source tree with initramfs enabled |
dpkg -i <package_name><version>-<debian_version><arch>.deb
|
install a local package to the system |
debi <package_name><version>-<debian_version><arch>.dsc
|
install local package(s) to the system |
dpkg --get-selections '*' >selection.txt
|
save dpkg level package selection state information
|
dpkg --set-selections <selection.txt
|
set dpkg level package selection state information
|
echo <package_name> hold | dpkg --set-selections
|
set dpkg level package selection state for a package to hold (equivalent to "aptitude hold <package_name> ")
|
Caution | |
---|---|
Lower level package tools such as " |
Please note the following.
All system configuration and installation commands require to be run from root.
Unlike aptitude
which uses regex (see Section 1.6.2, “Regular expressions”), other package management commands use pattern like shell glob (see Section 1.5.6, “Shell glob”).
apt-file(1) provided by the apt-file
package must run "apt-file update
" in advance.
configure-debian(8) provided by the configure-debian
package runs dpkg-reconfigure(8) as its backend.
dpkg-reconfigure(8) runs package scripts using debconf(1) as its backend.
"apt-get build-dep
", "apt-get source
" and "apt-cache showsrc
" commands require "deb-src
" entry in "/etc/apt/sources.list
".
dget(1), debuild(1), and debi(1) require devscripts
package.
See (re)packaging procedure using "apt-get source
" in Section 2.7.13, “Porting a package to the stable system”.
make-kpkg
command requires the kernel-package
package (see Section 9.7, “The kernel”).
See Section 12.11, “Making Debian package” for general packaging.
The installation of debsums
enables verification of installed package files against MD5sum values in the "/var/lib/dpkg/info/*.md5sums
" file with debsums(1). See Section 10.4.5, “The MD5 sum” for how MD5sum works.
Note | |
---|---|
Because MD5sum database may be tampered by the intruder, debsums(1) is of limited use as a security tool. It is only good for checking local modifications by the administrator or damage due to media errors. |
Many users prefer to follow the unstable release of the Debian system for its new features and packages. This makes the system more prone to be hit by the critical package bugs.
The installation of the apt-listbugs
package safeguards your system against critical bugs by checking Debian BTS automatically for critical bugs when upgrading with APT system.
The installation of the apt-listchanges
package provides important news in "NEWS.Debian
" when upgrading with APT system.
Although visiting Debian site http://packages.debian.org/ facilitates easy ways to search on the package meta data these days, let's look into more traditional ways.
The grep-dctrl(1), grep-status(1), and grep-available(1) commands can be used to search any file which has the general format of a Debian package control file.
The "dpkg -S <file_name_pattern>
" can be used search package names which contain files with the matching name installed by dpkg
. But this overlooks files created by the maintainer scripts.
If you need to make more elaborate search on the dpkg meta data, you need to run "grep -e regex_pattern *
" command in the "/var/lib/dpkg/info/
" directory. This makes you search words mentioned in package scripts and installation query texts.
If you wish to look up package dependency recursively, you should use apt-rdepends(8).
Let's learn how the Debian package management system works internally. This should help you to create your own solution to some package problems.
Meta data files for each distribution are stored under "dist/<codename>
" on each Debian mirror sites, e.g., "http://ftp.us.debian.org/debian/
". Its archive structure can be browsed by the web browser. There are 6 types of key meta data.
Table 2.14. The content of the Debian archive meta data
file | location | content |
---|---|---|
Release
|
top of distribution | archive description and integrity information |
Release.gpg
|
top of distribution |
signature file for the "Release " file signed with the archive key
|
Contents-<architecture>
|
top of distribution | list of all files for all the packages in the pertinent archive |
Release
|
top of each distribution/area/architecture combination | archive description used for the rule of apt_preferences(5) |
Packages
|
top of each distribution/area/binary-architecture combination |
concatenated debian/control for binary packages
|
Sources
|
top of each distribution/area/source combination |
concatenated debian/control for source packages
|
In the recent archive, these meta data are stored as the compressed and differential files to reduce network traffic.
Tip | |
---|---|
The top level " |
Each suite of the Debian archive has a top level "Release
" file, e.g., "http://ftp.us.debian.org/debian/dists/unstable/Release
", as follows.
Origin: Debian Label: Debian Suite: unstable Codename: sid Date: Sat, 14 May 2011 08:20:50 UTC Valid-Until: Sat, 21 May 2011 08:20:50 UTC Architectures: alpha amd64 armel hppa hurd-i386 i386 ia64 kfreebsd-amd64 kfreebsd-i386 mips mipsel powerpc s390 sparc Components: main contrib non-free Description: Debian x.y Unstable - Not Released MD5Sum: bdc8fa4b3f5e4a715dd0d56d176fc789 18876880 Contents-alpha.gz 9469a03c94b85e010d116aeeab9614c0 19441880 Contents-amd64.gz 3d68e206d7faa3aded660dc0996054fe 19203165 Contents-armel.gz ...
Note | |
---|---|
Here, you can find my rationale to use the "suite", and "codeneme" in Section 2.1.4, “Debian archive basics”. The "distribution" is used when referring to both "suite" and "codeneme". All archive "area" names offered by the archive are listed under "Component". |
The integrity of the top level "Release
" file is verified by cryptographic infrastructure called the secure apt.
The cryptographic signature file "Release.gpg
" is created from the authentic top level "Release
" file and the secret Debian archive key.
The public Debian archive key can be seeded into "/etc/apt/trusted.gpg
";
automatically by installing the keyring with the latest base-files
package, or
manually by gpg
or apt-key
tool with the latest public archive key posted on the ftp-master.debian.org .
The secure APT system verifies the integrity of the downloaded top level "Release
" file cryptographically by this "Release.gpg
" file and the public Debian archive key in "/etc/apt/trusted.gpg
".
The integrity of all the "Packages
" and "Sources
" files are verified by using MD5sum values in its top level "Release
" file. The integrity of all package files are verified by using MD5sum values in the "Packages
" and "Sources
" files. See debsums(1) and Section 2.4.2, “Verification of installed package files”.
Since the cryptographic signature verification is very CPU intensive process than the MD5sum value calculation, use of MD5sum value for each package while using cryptographic signature for the top level "Release
" file provides the good security with the performance (see Section 10.4, “Data security infrastructure”).
Tip | |
---|---|
The archive level " |
There are archive level "Release
" files for all archive locations specified by "deb
" line in "/etc/apt/sources.list
", such as "http://ftp.us.debian.org/debian/dists/unstable/main/binary-amd64/Release
" or "http://ftp.us.debian.org/debian/dists/sid/main/binary-amd64/Release
" as follows.
Archive: unstable Origin: Debian Label: Debian Component: main Architecture: amd64
Caution | |
---|---|
For " |
For some archives, such as experimental
, and squeeze-backports
, which contain packages which should not be installed automatically, there is an extra line, e.g., "http://ftp.us.debian.org/debian/dists/experimental/main/binary-amd64/Release
" as follows.
Archive: experimental Origin: Debian Label: Debian NotAutomatic: yes Component: main Architecture: amd64
Please note that for normal archives without "NotAutomatic: yes
", the default Pin-Priority value is 500, while for special archives with "NotAutomatic: yes
", the default Pin-Priority value is 1 (see apt_preferences(5) and Section 2.7.3, “Tweaking candidate version”).
When APT tools, such as aptitude
, apt-get
, synaptic
, apt-file
, auto-apt
…, are used, we need to update the local copies of the meta data containing the Debian archive information. These local copies have following file names corresponding to the specified distribution
, area
, and architecture
names in the "/etc/apt/sources.list
" (see Section 2.1.4, “Debian archive basics”).
"/var/lib/apt/lists/ftp.us.debian.org_debian_dists_<distribution>_Release
"
"/var/lib/apt/lists/ftp.us.debian.org_debian_dists_<distribution>_Release.gpg
"
"/var/lib/apt/lists/ftp.us.debian.org_debian_dists_<distribution>_<area>_binary-<architecture>_Packages
"
"/var/lib/apt/lists/ftp.us.debian.org_debian_dists_<distribution>_<area>_source_Sources
"
"/var/cache/apt/apt-file/ftp.us.debian.org_debian_dists_<distribution>_Contents-<architecture>.gz
" (for apt-file
)
First 4 types of files are shared by all the pertinent APT commands and updated from command line by "apt-get update
" and "aptitude update
". The "Packages
" meta data are updated if there is the "deb
" line in "/etc/apt/sources.list
". The "Sources
" meta data are updated if there is the "deb-src
" line in "/etc/apt/sources.list
".
The "Packages
" and "Sources
" meta data contain "Filename:
" stanza pointing to the file location of the binary and source packages. Currently, these packages are located under the "pool/
" directory tree for the improved transition over the releases.
Local copies of "Packages
" meta data can be interactively searched with the help of aptitude
. The specialized search command grep-dctrl(1) can search local copies of "Packages
" and "Sources
" meta data.
Local copy of "Contents-<architecture>
" meta data can be updated by "apt-file update
" and its location is different from other 4 ones. See apt-file(1). (The auto-apt
uses different location for local copy of "Contents-<architecture>.gz
" as default.)
In addition to the remotely fetched meta data, the APT tool after lenny
stores its locally generated installation state information in the "/var/lib/apt/extended_states
" which is used by all APT tools to track all auto installed packages.
In addition to the remotely fetched meta data, the aptitude
command stores its locally generated installation state information in the "/var/lib/aptitude/pkgstates
" which is used only by it.
All the remotely fetched packages via APT mechanism are stored in the "/var/cache/apt/archives
" until they are cleaned.
Debian package files have particular name structures.
Table 2.15. The name structure of Debian packages
package type | name structure |
---|---|
The binary package (a.k.a deb )
|
<package-name>_<epoch>:<upstream-version>-<debian.version>-<architecture>.deb
|
The binary package (a.k.a udeb )
|
<package-name>_<epoch>:<upstream-version>-<debian.version>-<architecture>.udeb
|
The source package (upstream source) |
<package-name>_<epoch>:<upstream-version>-<debian.version>.orig.tar.gz
|
The 1.0 source package (Debian changes)
|
<package-name>_<epoch>:<upstream-version>-<debian.version>.diff.gz
|
The 3.0 (quilt) source package (Debian changes)
|
<package-name>_<epoch>:<upstream-version>-<debian.version>.debian.tar.gz
|
The source package (description) |
<package-name>_<epoch>:<upstream-version>-<debian.version>.dsc
|
Tip | |
---|---|
Here only the basic source package formats are described. See more on dpkg-source(1). |
Table 2.16. The usable characters for each component in the Debian package names
name component | usable characters (regex) | existence |
---|---|---|
<package-name>
|
[a-z,A-Z,0-9,.,
|
required |
<epoch>:
|
[0-9]+:
|
optional |
<upstream-version>
|
[a-z,A-Z,0-9,.,
|
required |
<debian.version>
|
[a-z,A-Z,0-9,.,
|
optional |
Note | |
---|---|
You can check package version order by dpkg(1), e.g., " |
Note | |
---|---|
The debian-installer (d-i) uses |
dpkg(1) is the lowest level tool for the Debian package management. This is very powerful and needs to be used with care.
While installing package called "<package_name>
", dpkg
process it in the following order.
Unpack the deb file ("ar -x
" equivalent)
Execute "<package_name>.preinst
" using debconf(1)
Install the package content to the system ("tar -x
" equivalent)
Execute "<package_name>.postinst
" using debconf(1)
The debconf
system provides standardized user interaction with I18N and L10N (Chapter 8, I18N and L10N) supports.
Table 2.17. The notable files created by dpkg
file | description of contents |
---|---|
/var/lib/dpkg/info/<package_name>.conffiles
|
list of configuration files. (user modifiable) |
/var/lib/dpkg/info/<package_name>.list
|
list of files and directories installed by the package |
/var/lib/dpkg/info/<package_name>.md5sums
|
list of MD5 hash values for files installed by the package |
/var/lib/dpkg/info/<package_name>.preinst
|
package script run before the package installation |
/var/lib/dpkg/info/<package_name>.postinst
|
package script run after the package installation |
/var/lib/dpkg/info/<package_name>.prerm
|
package script run before the package removal |
/var/lib/dpkg/info/<package_name>.postrm
|
package script run after the package removal |
/var/lib/dpkg/info/<package_name>.config
|
package script for debconf system
|
/var/lib/dpkg/alternatives/<package_name>
|
the alternative information used by the update-alternatives command
|
/var/lib/dpkg/available
|
the availability information for all the package |
/var/lib/dpkg/diversions
|
the diversions information used by dpkg(1) and set by`dpkg-divert`(8) |
/var/lib/dpkg/statoverride
|
the stat override information used by dpkg(1) and set by`dpkg-statoverride`(8) |
/var/lib/dpkg/status
|
the status information for all the packages |
/var/lib/dpkg/status-old
|
the first-generation backup of the "var/lib/dpkg/status " file
|
/var/backups/dpkg.status*
|
the second-generation backup and older ones of the "var/lib/dpkg/status " file
|
The "status
" file is also used by the tools such as dpkg(1), "dselect update
" and "apt-get -u dselect-upgrade
".
The specialized search command grep-dctrl(1) can search the local copies of "status
" and "available
" meta data.
Tip | |
---|---|
In the debian-installer environment, the |
The Debian system has mechanism to install somewhat overlapping programs peacefully using update-alternatives(8). For example, you can make the vi
command select to run vim
while installing both vim
and nvi
packages.
$ ls -l $(type -p vi) lrwxrwxrwx 1 root root 20 2007-03-24 19:05 /usr/bin/vi -> /etc/alternatives/vi $ sudo update-alternatives --display vi ... $ sudo update-alternatives --config vi Selection Command ---------------------------------------------- 1 /usr/bin/vim *+ 2 /usr/bin/nvi Enter to keep the default[*], or type selection number: 1
The Debian alternatives system keeps its selection as symlinks in "/etc/alternatives/
". The selection process uses corresponding file in "/var/lib/dpkg/alternatives/
".
Stat overrides provided by the dpkg-statoverride(8) command are a way to tell dpkg(1) to use a different owner or mode for a file when a package is installed. If "--update
" is specified and file exists, it is immediately set to the new owner and mode.
Caution | |
---|---|
The direct alteration of owner or mode for a file owned by the package using |
Note | |
---|---|
I use the word file here, but in reality this can be any filesystem object that |
File diversions provided by the dpkg-divert(8) command are a way of forcing dpkg(1) not to install a file into its default location, but to a diverted location. The use of dpkg-divert
is meant for the package maintenance scripts. Its casual use by the system administrator is deprecated.
When running unstable
system, the administrator is expected to recover from broken package management situation.
Caution | |
---|---|
Some methods described here are high risk actions. You have been warned! |
If a desktop GUI program experienced instability after significant upstream version upgrade, you should suspect interferences with old local configuration files created by it. If it is stable under newly created user account, this hypothesis is confirmed. (This is a bug of packaging and usually avoided by the packager.)
To recover stability, you should move corresponding local configuration files and restart the GUI program. You may need to read old configuration file contents to recover configuration information later. (Do not erase them too quickly.)
Archive level package management systems, such as aptitude(8) or apt-get(1), do not even try to install packages with overlapped files using package dependencies (see Section 2.1.5, “Package dependencies”).
Errors by the package maintainer or deployment of inconsistently mixed source of archives (see Section 2.7.2, “Packages from mixed source of archives”) by the system administrator may create situation with incorrectly defined package dependencies. When you install a package with overlapped files using aptitude(8) or apt-get(1) under such situation, dpkg(1) which unpacks package ensures to return error to the calling program without overwriting existing files.
Caution | |
---|---|
The use of third party packages introduces significant system risks via maintainer scripts which are run with root privilege and can do anything to your system. The dpkg(1) command only protects against overwriting by the unpacking. |
You can work around such broken installation by removing the old offending package, <old-package>
, first.
$ sudo dpkg -P <old-package>
When a command in the package script returns error for some reason and the script exits with error, the package management system aborts their action and ends up with partially installed packages. When a package contains bugs in its removal scripts, the package may become impossible to remove and quite nasty.
For the package script problem of "<package_name>
", you should look into following package scripts.
"/var/lib/dpkg/info/<package_name>.preinst
"
"/var/lib/dpkg/info/<package_name>.postinst
"
"/var/lib/dpkg/info/<package_name>.prerm
"
"/var/lib/dpkg/info/<package_name>.postrm
"
Edit the offending package script from the root using following techniques.
disable the offending line by preceding "#
"
force to return success by appending the offending line with "|| true
"
Configure all partially installed packages with the following command.
# dpkg --configure -a
Since dpkg
is very low level package tool, it can function under the very bad situation such as unbootable system without network connection. Let's assume foo
package was broken and needs to be replaced.
You may still find cached copies of older bug free version of foo
package in the package cache directory: "/var/cache/apt/archives/
". (If not, you can download it from archive of http://snapshot.debian.net/ or copy it from package cache of a functioning machine.)
If you can boot the system, you may install it by the following command.
# dpkg -i /path/to/foo_<old_version>_<arch>.deb
Tip | |
---|---|
If system breakage is minor, you may alternatively downgrade the whole system as Section 2.7.10, “Emergency downgrading” using the higher level APT system. |
If your system is unbootable from hard disk, you should seek other ways to boot it.
Boot the system using the debian-installer CD in rescue mode.
Mount the unbootable system on the hard disk to "/target
".
Install older version of foo
package by the following.
# dpkg --root /target -i /path/to/foo_<old_version>_<arch>.deb
This example works even if the dpkg
command on the hard disk is broken.
Tip | |
---|---|
Any GNU/Linux system started by another system on hard disk, live GNU/Linux CD, bootable USB-key drive, or netboot can be used similarly to rescue broken system. |
If attempting to install a package this way fails due to some dependency violations and you really need to do this as the last resort, you can override dependency using dpkg
's "--ignore-depends
", "--force-depends
" and other options. If you do this, you need to make serious effort to restore proper dependency later. See dpkg(8) for details.
Note | |
---|---|
When your system is seriously broken, you should make a full backup of system to a safe place (see Section 10.1.6, “Backup and recovery”) and should perform a clean installation. This is less time consuming and produces better results in the end. |
If "/var/lib/dpkg/status
" becomes corrupt for any reason, the Debian system loses package selection data and suffers severely. Look for the old "/var/lib/dpkg/status
" file at "/var/lib/dpkg/status-old
" or "/var/backups/dpkg.status.*
".
Keeping "/var/backups/
" in a separate partition may be a good idea since this directory contains lots of important system data.
For serious breakage, I recommend to make fresh re-install after making backup of the system. Even if everything in "/var/
" is gone, you can still recover some information from directories in "/usr/share/doc/
" to guide your new installation.
Reinstall minimal (desktop) system.
# mkdir -p /path/to/old/system
Mount old system at "/path/to/old/system/
".
# cd /path/to/old/system/usr/share/doc # ls -1 >~/ls1.txt # cd /usr/share/doc # ls -1 >>~/ls1.txt # cd # sort ls1.txt | uniq | less
Then you are presented with package names to install. (There may be some non-package names such as "texmf
".)
You can seek packages which satisfy your needs with aptitude
from the package description or from the list under "Tasks".
When you encounter more than 2 similar packages and wonder which one to install without "trial and error" efforts, you should use some common sense. I consider following points are good indications of preferred packages.
Essential: yes > no
Component: main > contrib > non-free
Priority: required > important > standard > optional > extra
Tasks: packages listed in tasks such as "Desktop environment"
Packages selected by the dependency package (e.g., python2.4
by python
)
Popcon: higher in the vote and install number
Changelog: regular updates by the maintainer
BTS: No RC bugs (no critical, no grave, and no serious bugs)
BTS: responsive maintainer to bug reports
BTS: higher number of the recently fixed bugs
BTS: lower number of remaining non-wishlist bugs
Debian being a volunteer project with distributed development model, its archive contains many packages with different focus and quality. You must make your own decision what to do with them.
Caution | |
---|---|
Installing packages from mixed source of archives is not supported by the official Debian distribution except for officially supported particular combinations of archives such as |
Here is an example of operations to include specific newer upstream version packages found in unstable
while tracking testing
for single occasion.
Change the "/etc/apt/sources.list
" file temporarily to single "unstable
" entry.
Run "aptitude update
".
Run "aptitude install <package-name>
".
Recover the original "/etc/apt/sources.list
" file for testing
.
Run "aptitude update
".
You do not create the "/etc/apt/preferences
" file nor need to worry about apt-pinning with this manual approach. But this is very cumbersome.
Caution | |
---|---|
When using mixed source of archives, you must ensure compatibility of packages by yourself since the Debian does not guarantee it. If package incompatibility exists, you may break system. You must be able to judge these technical requirements. The use of mixed source of random archives is completely optional operation and its use is not something I encourage you to use. |
General rules for installing packages from different archives are followings.
Non-binary packages ("Architecture: all
") are safer to install.
documentation packages: no special requirements
interpreter program packages: compatible interpreter must be available
Binary packages (non "Architecture: all
") usually face many road blocks and unsafe to install.
Note | |
---|---|
In order to make a package to be safer to install, some commercial non-free binary program packages may be provided with completely statically linked libraries. You should still check ABI compatibility issues etc. for them. |
Note | |
---|---|
Except to avoid broken package for a short term, installing binary packages from officially unsupported archives is generally bad idea. This is true even if you use apt-pinning (see Section 2.7.3, “Tweaking candidate version”). You should consider chroot or similar techniques (see Section 9.8, “Virtualized system”) to run programs from different archives. |
Without the "/etc/apt/preferences
" file, APT system choses the latest available version as the candidate version using the version string. This is the normal state and most recommended usage of APT system. All officially supported combinations of archives do not require the "/etc/apt/preferences
" file since some archives which should not be used as the automatic source of upgrades are marked as NotAutomatic and dealt properly.
Tip | |
---|---|
The version string comparison rule can be verified with, e.g., " |
When you install packages from mixed source of archives (see Section 2.7.2, “Packages from mixed source of archives”) regularly, you can automate these complicated operations by creating the "/etc/apt/preferences
" file with proper entries and tweaking the package selection rule for candidate version as described in apt_preferences(5). This is called apt-pinning.
Warning | |
---|---|
Use of apt-pinning by a novice user is sure call for major troubles. You must avoid using apt-pinning except when you absolutely need it. |
Caution | |
---|---|
When using apt-pinning, you must ensure compatibility of packages by yourself since the Debian does not guarantee it. The apt-pinning is completely optional operation and its use is not something I encourage you to use. |
Caution | |
---|---|
Archive level Release files (see Section 2.5.3, “Archive level "Release" files”) are used for the rule of apt_preferences(5). Thus apt-pinning works only with "suite" name for normal Debian archives and security Debian archives. (This is different from Ubuntu archives). For example, you can do " |
Caution | |
---|---|
When you use non-Debian archive as a part of apt-pinning, you should check what they are intended for and also check their credibility. For example, Ubuntu and Debian are not meant to be mixed. |
Note | |
---|---|
Even if you do not create the " |
Here is a simplified explanation of apt-pinning technique.
APT system choses highest Pin-Priority upgrading package from available package sources defined in the "/etc/apt/sources.list
" file as the candidate version package. If the Pin-Priority of the package is larger than 1000, this version restriction for upgrading is dropped to enable downgrading (see Section 2.7.10, “Emergency downgrading”).
Pin-Priority value of each package is defined by "Pin-Priority" entries in the "/etc/apt/preferences
" file or uses its default value.
Table 2.18. List of notable Pin-Priority values for apt-pinning technique.
Pin-Priority | apt-pinning effects to the package |
---|---|
1001 | install the package even if this constitutes a downgrade of the package |
990 | used as the default for the target release archive |
500 | used as the default for the normal archive |
100 | used as the default for the NotAutomatic and ButAutomaticUpgrades archive |
100 | used for the installed package |
1 | used as the default for the NotAutomatic archive |
-1 | never install the package even if recommended |
The target release archive can be set by several methods.
"/etc/apt/apt.conf
" configuration file with "APT::Default-Release "stable";
" line
command line option, e.g., "apt-get install -t testing some-package
"
The NotAutomatic and ButAutomaticUpgrades archive is set by archive server having its archive level Release file (see Section 2.5.3, “Archive level "Release" files”) containing both "NotAutomatic: yes
" and "ButAutomaticUpgrades: yes
". The NotAutomatic archive is set by archive server having its archive level Release file containing only "NotAutomatic: yes
".
The apt-pinning situation of <package> from multiple archive sources is displayed by "apt-cache policy <package>
".
A line started with "Package pin:
" lists the package version of pin if association just with <package> is defined, e.g., "Package pin: 0.190
".
No line with "Package pin:
" exists if no association just with <package> is defined.
The Pin-Priority value associated just with <package> is listed right side of all version strings, e.g., "0.181 700
".
"0
" is listed right side of all version strings if no association just with <package> is defined, e.g., "0.181 0
".
The Pin-Priority values of archives (defined as "Package: *
" in the "/etc/apt/preferences
" file) are listed left side of all archive paths, e.g., "100 http://backports.debian.org/debian-backports/ squeeze-backports/main Packages
".
There are squeeze-updates and backports.debian.org archives which provide updgrade packages for stable
(squeeze
).
In order to use these archives, you list all required archives in the "/etc/apt/sources.list
" file as the following.
deb http://ftp.us.debian.org/debian/ squeeze main contrib non-free deb http://security.debian.org/ squeeze/updates main contrib deb http://ftp.us.debian.org/debian/ squeeze-updates main contrib non-free deb http://backports.debian.org/debian-backports/ squeeze-backports main contrib non-free
There is no need to set Pin-Priority value explicitly in the "/etc/apt/preferences
" file. When newer packages become available, the default configuration provides most reasonable upgrades (see Section 2.5.3, “Archive level "Release" files”).
All installed older packages are upgraded to newer ones from squeeze-updates
.
Only manually installed older packages from squeeze-backports
are upgraded to newer ones from squeeze-backports
.
Whenever you wish to install a package named "<package-name>
" with its dependency from squeeze-backports
archive manually, you use following command while switching target release with "-t
" option.
$ sudo apt-get install -t squeeze-backports <package-name>
If you wish not to pull in particular packages automatically by "Recommends", you must create the "/etc/apt/preferences
" file and explicitly list all those packages at the top of it as the following.
Package: <package-1> Pin: version * Pin-Priority: -1 Package: <package-2> Pin: version * Pin-Priority: -1
Here is an example of apt-pinning technique to include specific newer upstream version packages found in unstable
regularly upgraded while tracking testing
. You list all required archives in the "/etc/apt/sources.list
" file as the following.
deb http://ftp.us.debian.org/debian/ testing main contrib non-free deb http://ftp.us.debian.org/debian/ unstable main contrib non-free deb http://security.debian.org/ testing/updates main contrib
Set the "/etc/apt/preferences
" file as as the following.
Package: * Pin: release a=unstable Pin-Priority: 100
When you wish to install a package named "<package-name>
" with its dependencies from unstable
archive under this configuration, you issue the following command which switches target release with "-t
" option (Pin-Priority of unstable
becomes 990.).
$ sudo apt-get install -t unstable <package-name>
With this configuration, usual execution of "apt-get upgrade
" and "apt-get dist-upgrade
" (or "aptitude safe-upgrade
" and "aptitude full-upgrade
") upgrades packages which were installed from testing
archive using current testing
archive and packages which were installed from unstable
archive using current unstable
archive.
Caution | |
---|---|
Be careful not to remove " |
Tip | |
---|---|
I usually edit the " |
Tip | |
---|---|
If " |
If you wish to track particular packages in unstable
automatically without initial "-t unstable
" installation, you must create the "/etc/apt/preferences
" file and explicitly list all those packages at the top of it as the following.
Package: <package-1> Pin: release a=unstable Pin-Priority: 700 Package: <package-2> Pin: release a=unstable Pin-Priority: 700
These set Pin-Priority value for each specific package. For example, in order to track the latest unstable
version of this "Debian Reference" in English, you should have following entries in the "/etc/apt/preferences
" file.
Package: debian-reference-en Pin: release a=unstable Pin-Priority: 700 Package: debian-reference-common Pin: release a=unstable Pin-Priority: 700
Tip | |
---|---|
This apt-pinning technique is valid even when you are tracking |
Here is another example of apt-pinning technique to include specific newer upstream version packages found in experimental
while tracking unstable
. You list all required archives in the "/etc/apt/sources.list
" file as the following.
deb http://ftp.us.debian.org/debian/ unstable main contrib non-free deb http://ftp.us.debian.org/debian/ experimental main contrib non-free deb http://security.debian.org/ testing/updates main contrib
The default Pin-Priority value for experimental
archive is always 1 (<<100) since it is NotAutomatic archive (see Section 2.5.3, “Archive level "Release" files”). There is no need to set Pin-Priority value explicitly in the "/etc/apt/preferences
" file just to use experimental
archive unless you wish to track particular packages in it automatically for next upgrading.
The apt
package comes with its own cron script "/etc/cron.daily/apt
" to support the automatic download of packages. This script can be enhanced to perform the automatic upgrade of packages by installing the unattended-upgrades
package. These can be customized by parameters in "/etc/apt/apt.conf.d/02backup
" and "/etc/apt/apt.conf.d/50unattended-upgrades
" as described in "/usr/share/doc/unattended-upgrades/README
".
The unattended-upgrades
package is mainly intended for the security upgrade for the stable
system. If the risk of breaking an existing stable
system by the automatic upgrade is smaller than that of the system broken by the intruder using its security hole which has been closed by the security update, you should consider using this automatic upgrade with configuration parameters as the following.
APT::Periodic::Update-Package-Lists "1"; APT::Periodic::Download-Upgradeable-Packages "1"; APT::Periodic::Unattended-Upgrade "1";
If you are running an unstable
system, you do not want to use the automatic upgrade since it certainly breaks system some day. Even for such unstable
case, you may still want to download packages in advance to save time for the interactive upgrade with configuration parameters as the following.
APT::Periodic::Update-Package-Lists "1"; APT::Periodic::Download-Upgradeable-Packages "1"; APT::Periodic::Unattended-Upgrade "0";
If you want to limit the download bandwidth for APT to e.g. 800Kib/sec (=100kiB/sec), you should configure APT with its configuration parameter as the following.
APT::Acquire::http::Dl-Limit "800";
Caution | |
---|---|
Downgrading is not officially supported by the Debian by design. It should be done only as a part of emergency recovery process. Despite of this situation, it is known to work well in many incidents. For critical systems, You should backup all important data on the system after the recovery operation and re-install the new system from the scratch. |
You may be lucky to downgrade from newer archive to older archive to recover from broken system upgrade by manipulating candidate version (see Section 2.7.3, “Tweaking candidate version”). This is lazy alternative to tedious actions of many "dpkg -i <broken-package>_<old-version>.deb
" commands (see Section 2.6.4, “Rescue with the dpkg command”).
Search lines in the "/etc/apt/sources.list
" file tracking unstable
as the following.
deb http://ftp.us.debian.org/debian/ sid main contrib non-free
Replace it with the following to track testing
.
deb http://ftp.us.debian.org/debian/ wheezy main contrib non-free
Set the "/etc/apt/preferences
" file as the following.
Package: * Pin: release a=testing Pin-Priority: 1010
Run "apt-get dist-upgrade
" to force downgrading of packages across the system.
Remove this special "/etc/apt/preferences
" file after this emergency downgrading.
Tip | |
---|---|
It is good idea to remove (not purge!) as much packages to minimize dependency problems. You may need to manually remove and install some packages to get system downgraded. Linux kernel, bootloader, udev, PAM, APT, and networking related packages and their configuration files require special attention. |
Although the maintainer name listed in "/var/lib/dpkg/available
" and "/usr/share/doc/package_name/changelog
" provide some information on "who is behind the packaging activity", the actual uploader of the package is somewhat obscure. who-uploads(1) in the devscripts
package identifies the actual uploader of Debian source packages.
If you are to compile a program from source to replace the Debian package, it is best to make it into a real local debianized package (*.deb
) and use private archive.
If you chose to compile a program from source and to install them under "/usr/local
" instead, you may need to use equivs
as a last resort to satisfy the missing package dependency.
Package: equivs Priority: extra Section: admin Description: Circumventing Debian package dependencies This is a dummy package which can be used to create Debian packages, which only contain dependency information.
For partial upgrades of the stable
system, rebuilding a package within its environment using the source package is desirable. This avoids massive package upgrades due to their dependencies.
Add the following entries to the "/etc/apt/sources.list
" of a stable
system.
deb-src http://http.us.debian.org/debian unstable main contrib non-free
Install required packages for the compilation and download the source package as the following.
# apt-get update # apt-get dist-upgrade # apt-get install fakeroot devscripts build-essential $ apt-get build-dep foo $ apt-get source foo $ cd foo*
Adjust installed packages if needed.
Execute the following.
$ dch -i
Bump package version, e.g. one appended with "+bp1
" in "debian/changelog
"
Build packages and install them to the system as the following.
$ debuild $ cd .. # debi foo*.changes
Since mirroring whole subsection of Debian archive wastes disk space and network bandwidth, deployment of a local proxy server for APT is desirable consideration when you administer many systems on LAN. APT can be configure to use generic web (http) proxy servers such as squid
(see Section 6.10, “Other network application servers”) as described in apt.conf(5) and in "/usr/share/doc/apt/examples/configure-index.gz
". The "$http_proxy
" environment variable can be used to override proxy server setting in the "/etc/apt/apt.conf
" file.
There are proxy tools specially for Debian archive. You should check BTS before using them.
Table 2.19. List of the proxy tools specially for Debian archive
package | popcon | size | description |
---|---|---|---|
approx
|
http://qa.debian.org/popcon.php?package=approx | 3537 | caching proxy server for Debian archive files (compiled OCaml program) |
apt-cacher
|
http://qa.debian.org/popcon.php?package=apt-cacher | 311 | Caching proxy for Debian package and source files (Perl program) |
apt-cacher-ng
|
http://qa.debian.org/popcon.php?package=apt-cacher-ng | 1132 | Caching proxy for distribution of software packages (compiled C++ program) |
debtorrent
|
http://qa.debian.org/popcon.php?package=debtorrent | 1185 | Bittorrent proxy for downloading Debian packages (Python program) |
Caution | |
---|---|
When Debian reorganizes its archive structure, these specialized proxy tools tend to require code rewrites by the package maintainer and may not be functional for a while. On the other hand, generic web (http) proxy servers are more robust and easier to cope with such changes. |
Here is an example for creating a small public package archive compatible with the modern secure APT system (see Section 2.5.2, “Top level "Release" file and authenticity”). Let's assume few things.
Account name: "foo
"
Host name: "www.example.com
"
Required packages: apt-utils
, gnupg
, and other packages
URL: "http://www.example.com/~foo/
" ( → "/home/foo/public_html/index.html
")
Architecture of packages: "amd64
"
Create an APT archive key of Foo on your server system as the following.
$ ssh foo@www.example.com $ gpg --gen-key ... $ gpg -K ... sec 1024D/3A3CB5A6 2008-08-14 uid Foo (ARCHIVE KEY) <foo@www.example.com> ssb 2048g/6856F4A7 2008-08-14 $ gpg --export -a 3A3CB5A6 >foo.public.key
Publish the archive key file "foo.public.key
" with the key ID "3A3CB5A6
" for Foo
Create an archive tree called "Origin: Foo" as the following.
$ umask 022 $ mkdir -p ~/public_html/debian/pool/main $ mkdir -p ~/public_html/debian/dists/unstable/main/binary-amd64 $ mkdir -p ~/public_html/debian/dists/unstable/main/source $ cd ~/public_html/debian $ cat > dists/unstable/main/binary-amd64/Release << EOF Archive: unstable Version: 4.0 Component: main Origin: Foo Label: Foo Architecture: amd64 EOF $ cat > dists/unstable/main/source/Release << EOF Archive: unstable Version: 4.0 Component: main Origin: Foo Label: Foo Architecture: source EOF $ cat >aptftp.conf <<EOF APT::FTPArchive::Release { Origin "Foo"; Label "Foo"; Suite "unstable"; Codename "sid"; Architectures "amd64"; Components "main"; Description "Public archive for Foo"; }; EOF $ cat >aptgenerate.conf <<EOF Dir::ArchiveDir "."; Dir::CacheDir "."; TreeDefault::Directory "pool/"; TreeDefault::SrcDirectory "pool/"; Default::Packages::Extensions ".deb"; Default::Packages::Compress ". gzip bzip2"; Default::Sources::Compress "gzip bzip2"; Default::Contents::Compress "gzip bzip2"; BinDirectory "dists/unstable/main/binary-amd64" { Packages "dists/unstable/main/binary-amd64/Packages"; Contents "dists/unstable/Contents-amd64"; SrcPackages "dists/unstable/main/source/Sources"; }; Tree "dists/unstable" { Sections "main"; Architectures "amd64 source"; }; EOF
You can automate repetitive updates of APT archive contents on your server system by configuring dupload
.
Place all package files into "~foo/public_html/debian/pool/main/
" by executing "dupload -t foo changes_file
" in client while having "~/.dupload.conf
" containing the following.
$cfg{'foo'} = { fqdn => "www.example.com", method => "scpb", incoming => "/home/foo/public_html/debian/pool/main", # The dinstall on ftp-master sends emails itself dinstall_runs => 1, }; $cfg{'foo'}{postupload}{'changes'} = " echo 'cd public_html/debian ; apt-ftparchive generate -c=aptftp.conf aptgenerate.conf; apt-ftparchive release -c=aptftp.conf dists/unstable >dists/unstable/Release ; rm -f dists/unstable/Release.gpg ; gpg -u 3A3CB5A6 -bao dists/unstable/Release.gpg dists/unstable/Release'| ssh foo@www.example.com 2>/dev/null ; echo 'Package archive created!'";
The postupload hook script initiated by dupload(1) creates updated archive files for each upload.
You can add this small public archive to the apt-line of your client system by the following.
$ sudo bash # echo "deb http://www.example.com/~foo/debian/ unstable main" \ >> /etc/apt/sources.list # apt-key add foo.public.key
Tip | |
---|---|
If the archive is located on the local filesystem, you can use " |
You can make a local copy of the package and debconf selection states by the following.
# dpkg --get-selections '*' > selection.dpkg # debconf-get-selections > selection.debconf
Here, "*
" makes "selection.dpkg
" to include package entries for "purge" too.
You can transfer these 2 files to another computer, and install there with the following.
# dselect update # debconf-set-selections < myselection.debconf # dpkg --set-selections < myselection.dpkg # apt-get -u dselect-upgrade # or dselect install
If you are thinking about managing many servers in a cluster with practically the same configuration, you should consider to use specialized package such as fai
to manage the whole system.
alien(1) enables the conversion of binary packages provided in Red Hat rpm
, Stampede slp
, Slackware tgz
, and Solaris pkg
file formats into a Debian deb
package. If you want to use a package from another Linux distribution than the one you have installed on your system, you can use alien
to convert it from your preferred package format and install it. alien
also supports LSB packages.
Warning | |
---|---|
alien(1) should not be used to replace essential system packages, such as |
The current "*.deb
" package contents can be extracted without using dpkg(1) on any Unix-like environment using standard ar(1) and tar(1).
# ar x /path/to/dpkg_<version>_<arch>.deb # ls total 24 -rw-r--r-- 1 bozo bozo 1320 2007-05-07 00:11 control.tar.gz -rw-r--r-- 1 bozo bozo 12837 2007-05-07 00:11 data.tar.gz -rw-r--r-- 1 bozo bozo 4 2007-05-07 00:11 debian-binary # mkdir control # mkdir data # tar xvzf control.tar.gz -C control # tar xvzf data.tar.gz -C data
You can also browse package content using the mc
command.
You can learn more on the package management from following documentations.
Primary documentations on the package management:
aptitude(8), dpkg(1), tasksel(8), apt-get(8), apt-config(8), apt-key(8), sources.list(5), apt.conf(5), and apt_preferences(5);
"/usr/share/doc/apt-doc/guide.html/index.html
" and "/usr/share/doc/apt-doc/offline.html/index.html
" from the apt-doc
package; and
"/usr/share/doc/aptitude/html/en/index.html
" from the aptitude-doc-en
package.
Official and detailed documentations on the Debian archive:
Tutorial for building of a Debian package for Debian users: