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5.2. The Debian Package Manager

Debian GNU/Linux provides several package management tools, primarily intended to facilitate the building, installation, and management of binary packages. Debian package names generally end in .deb. The Debian package management tools include:

dpkg

Until recently, the most important of the Debian packaging tools and still the primary package management program. Used to install or uninstall packages or as a frontend to dpkg-deb.

dpkg-deb

Lower-level packaging tool. Used to create and manage the Debian package archives. Accepts and executes commands from dpkg or can be called directly.

dselect

An interactive frontend to dpkg.

apt-get

The currently available piece of the Advanced Package Tool (APT), which is still being developed and is intended to be a modern, user-friendly package management tool. Can be run from the command line or selected as a method from dselect. One of the features of apt-get is that you can use it to get and install packages across the Internet by specifying an ftp:// or http:// URL. Another feature is that you can use it to upgrade all packages currently installed on your system in a single operation.

5.2.1. Files

Some important files used by the Debian package management tools are:

control

Comes with each package; documents dependencies; contains the name and version of the package, a description, maintainer, installed size, and so on.

conffiles

Comes with each package and contains a list of the configuration files associated with the package.

preinst, postinst, prerm, postrm

Scripts that can be included in a package to be run before installation, after installation, before removal, or after removal of the package.

/var/lib/dpkg/available

Contains information about packages available on the system.

/var/lib/dpkg/status

Contains information about the status of packages available on the system.

/etc/apt/sources.list

A list for APT of package sources, used to locate packages. The sources are listed one per line, in order of preference.

/etc/apt/apt.conf

The main APT configuration file.

5.2.2. Package States and Selection States

The possible states that a package can be in are:

config-files

Only the configuration files for the package are present on the system.

half-configured

The package is unpacked and configuration was started but not completed.

half-installed

Installation was started but not completed.

installed

The package is unpacked and configured.

not-installed

The package is not installed.

unpacked

The package is unpacked but not configured.

The possible package selection states are:

deinstall

The package has been selected for deinstallation (i.e., for removal of everything but configuration files).

install

The package has been selected for installation.

purge

The package has been selected to be purged (i.e., for removal of everything including the configuration files).

5.2.3. Package Flags

There are two possible package flags that can be set for a package. They are:

hold

The package is not to be handled by dpkg, unless forced with the --force-hold option.

reinst-required

The package is broken and needs to be reinstalled. Such a package cannot be removed, unless forced with the --force-reinstreq option.

5.2.4. Scripts

In addition to the commands described in the next subsection, several shell and Perl scripts are included with the package manager for use in building packages:

dpkg-buildpackage

Help automate package building. Shell script.

dpkg-distaddfile

Add an entry for a file to debian/files. Perl script.

dpkg-genchanges

Generate an upload control file from the information in an unpacked, built, source tree and the files it has generated. Perl script.

dpkg-gencontrol

Read information from an unpacked source tree and display a binary package control file on standard output. Perl script.

dpkg-name

Rename Debian packages to their full package names. Shell script.

dpkg-parsechangelog

Read and parse the changelog from an unpacked source tree and write the information to standard output in machine-readable form. Perl script.

dpkg-scanpackages

Create a Packages file from a tree of binary packages. The Packages file is used by dselect to provide a list of packages available for installation. Perl script.

dpkg-shlibdeps

Calculate shared library dependencies for named executables. Perl script.

dpkg-source

Pack and unpack Debian source archives. Perl script.

5.2.5. Debian Package Manager Command Summary

apt-cdrom

apt-cdrom [options] command

Add a new CD-ROM to APT's list of available sources. Currently, the only command is add, which is required (except with the --help option). The database of CD-ROM IDs that APT maintains is /var/state/apt/cdroms.list.

Options

Options can be specified on the command line or they may be set in the configuration file. Boolean options set in the configuration file can be overridden on the command line in a number of different ways, a couple of which are --no-opt and -opt=no, where opt is the single-character or full name of the option.

-a, --thorough

Do a thorough package scan. May be needed with some old Debian CD-ROMs.

-c, --config-file

Specify a configuration file to be read after the default configuration file.

-d, --cdrom

Specify the CD-ROM mount point, which must be listed in /etc/fstab. The configuration option is Acquire::cdrom::mount.

-f, --fast

Do a fast copy, assuming the files are valid and don't all need checking. Specify this only if this disk has been run before without error. The configuration option is APT::CDROM::Fast.

-h, --help

Print help message and exit.

-m, --no-mount

Don't mount or unmount the mount point. The configuration option is APT::CDROM::NoMount.

-n, --just-print, --recon, --no-act

Check everything, but don't actually make any changes. The configuration option is APT::CDROM::NoAct.

-o, --option

Set a configuration option. Syntax is -o group::tool=option (e.g., APT::CDROM=Fast).

-r, --rename

Prompt for a new label and rename the disk to the new value. The configuration option is APT::CDROM::Rename.

-v, --version

Print the version information and exit.

apt-get

apt-get [options] command [package...]

A command-line tool for handling packages. Will eventually be a backend to APT.

Commands

autoclean

Like clean, but remove only package files that can no longer be downloaded.

clean

Clear the local repository of retrieved package files.

check

Update the package cache and check for broken packages.

dist-upgrade

Like upgrade but also handle dependencies intelligently.

dselect-upgrade

Used together with dselect. Track the changes made by dselect to the Status field of available packages and take actions necessary to realize that status.

install package...

Install one or more packages. Specify the package name, not the full filename. Other required packages also are retrieved and installed. With a hyphen appended to the package name, the package is removed if it is already installed.

remove package...

Remove one or more packages. Specify the package name, not the full filename. With a plus sign appended to the name, the package is installed.

source package...

Find source packages and download them into the current directory. If specified with --compile, the source packages are compiled into binary packages. With --download-only, the source packages are not unpacked.

update

Resynchronize the package overview files from their sources. Must be done before an upgrade or dist-upgrade.

upgrade

Install the latest versions of all packages currently installed. Run update first.

Options

Options can be specified on the command line or they may be set in the configuration file. Boolean options set in the configuration file can be overridden on the command line in one of several ways, a couple of which are --no-opt and -opt=no, where opt is the single-character or full name of the option.

-b, --compile, --build

Compile source packages after download.

-c, --config-file

Specify a configuration file to read after the default.

-d, --download-only

Retrieve package files, but don't unpack or install them. The configuration option is APT::Get::Download-only.

-f, --fix-broken

Try to fix a system with broken dependencies. Can be used alone or with a command. The configuration option is APT::Get::Fix-Broken.

--force-yes

Force yes. Causes APT to continue without prompting if it is doing something that could damage your system. Use with great caution and only if absolutely necessary. The configuration option is APT::Get::force-yes.

-h, --help

Display a help message and exit.

--ignore-hold

Ignore a hold placed on a package. Use with dist-upgrade to override many undesired holds. The configuration option is APT::Get::Ignore-Hold.

-m, --ignore-missing, --fix-missing

Ignore missing or corrupted packages or packages that cannot be retrieved. Can cause problems when used with -f.

--no-download

Disable package downloading; use with --ignore-missing to force APT to use only the packages that have already been downloaded.

--no-upgrade

Do not upgrade packages. Use with install to prevent upgrade of packages that are already installed. The configuration option is APT::Get::no-upgrade.

-o, --option

Set a configuration option. Syntax is -o group::tool=option (e.g., APT::Get=force-yes).

--print-uris

Print URIs of files instead of fetching them. Print path, destination filename, size, and expected MD5 hash. The configuration option is APT::Get::Print-URIs.

-q, --quiet

Quiet. Omit progress indicators, produce only logging output. Add a q to make even quieter.

-s, --simulate, --just-print, --dry-run, --recon, --no-act

Go through the motions, but don't actually make any changes to the system. The configuration option is APT::Get::Simulate.

-u, --show-upgraded

Print a list of all packages to be upgraded. The configuration option is APT::Get::Show-Upgraded.

-v, --version

Display the version and exit.

-y, --yes, --assume-yes

Automatically reply "yes" to prompts and run noninteractively. Abort if there is an error. The configuration option is APT::Get::Assume-Yes.

dpkg

dpkg [options] action

A tool for installing, managing, and building packages. Serves as a frontend to dpkg-deb.

dpkg actions

These actions are carried out by dpkg itself:

-i pkgfile, --install pkgfile

Install the package specified as pkgfile. With -R or --recursive, pkgfile must be a directory.

--unpack pkgfile

Unpack the package, but don't configure it. With -R or --recursive, pkgfile must be a directory.

--configure [packages|-a|--pending]

Reconfigure one or more unpacked packages. If -a or --pending is given instead of packages, configure all packages that are unpacked but not configured.

-r, --remove [packages|-a|--pending]
--purge [packages|-a|--pending]

Remove or purge one or more installed packages. Removal gets rid of everything except the configuration files listed in debian/conffiles; purging also removes the configuration files. If -a or --pending is given instead of packages, dpkg removes or purges all packages that are unpacked and marked (in /var/lib/dpkg/status) for removing or purging.

--print-avail package

Print the details about package from /var/lib/dpkg/available.

--update-avail pkgs-file
--merge-avail pkgs-file

Update the record of available files kept in /var/lib/dpkg/available. This information is used by dpkg and dselect to determine what packages are available. Update will replace the information with the contents of the pkgs-file, distributed as Packages. Merge combines the information from Packages with the existing information.

-A pkgfile, --record-avail pkgfile

Update the record of available files kept in /var/lib/dpkg/available with information from pkgfile. This information is used by dpkg and dselect to determine what packages are available. With -R or --recursive, pkgfile must be a directory.

--forget-old-unavail

Forget about uninstalled unavailable packages.

--clear-avail

Remove existing information about what packages are available.

-l, --list [pkg-name-pattern]

List all packages whose names match the specified pattern. With no pattern, list all packages in /var/lib/dpkg/available. The pattern can include standard shell wildcard characters and may have to be quoted to prevent the shell from doing filename expansion.

-s packages, --status packages

Report the status of one or more packages by displaying the entry in the status database /var/lib/dpkg/status.

-C, --audit

Search for partially installed packages and suggest how to get them working.

--get-selections [pattern]

Get list of package selections and write to standard output. With pattern specified, write selections that match the pattern.

--set-selections

Set package selections based on input file read from standard input.

--yet-to-unpack

Search for uninstalled packages that have been selected for installation.

-L packages, --listfiles packages

List installed files that came from the specified package or packages.

-S filename-pattern, --search filename-pattern

Search installed packages for a filename. The pattern can include standard shell wildcard characters and may have to be quoted to prevent the shell from doing filename expansion.

--print-architecture

Print target architecture.

--print-gnu-build-architecture

Print the GNU version of the target architecture.

--print-installation-architecture

Print host architecture for installation.

--compare-versions ver1 op ver2

Perform a binary comparison of two version numbers. The operators lt le eq ne ge gt treat a missing version as earlier. The operators lt-nl le-nl ge-nl gt-nl treat a missing version as later (where nl is "not later"). There is a third set of operators (< << <= = >= >> >) that is provided for compatibility with control-file syntax. dpkg returns zero for success (i.e., the condition is satisfied) and nonzero otherwise.

--help

Print help message and exit.

--force-help

Print help message about the --force-list options and exit.

-Dh, --debug=help

Print debugging help message and exit.

--license

Print dpkg license information and exit. Accepts the spelling --licence in addition to --license.

--version

Print dpkg version information and exit.

dpkg-deb actions

The following actions can be specified for dpkg and are passed to dpkg-deb for execution. Also see dpkg-deb.

-b dir [archive], --build dir [archive]

Build a package.

-c archive, --contents archive

List the contents of a package.

-e, --control archive dir

Extract control information from a package.

-f archive [control-fields], --field archive [control-fields]

Display the control field or fields of a package.

-I archive [control-files], --info archive [control-files]

Show information about a package.

--fsys-tarfile archive

Display the filesystem tar- file contained by a package.

-x archive dir, --extract archive dir

Extract the files from a package.

-X archive dir, --vextract archive dir

Extract and display the filenames from a package.

Options

--abort-after=num

Abort processing after num errors. Default is 50.

-B, --auto-deconfigure

When a package is removed, automatically deconfigure any other package that depended on it.

-Doctal, --debug=octal

Turn on debugging, with the octal value specifying the desired level of debugging information. Use -Dh or --debug=help to display the possible values. You can OR the values to get the desired output.

-E, --skip-same-version

Don't install the package if this version is already installed.

--force-list, --no-force-list, --refuse-list

Force or refuse to force an operation. list is specified as a comma-separated item of options. With --force, a warning is printed, but processing continues. --refuse and --no-force cause processing to stop with an error. The force/refuse options are:

architecture

Process even if intended for a different architecture.

auto-select

Select or deselect packages to install or remove them. Forced by default.

bad-path

Some programs are missing from the path.

configure-any

Configure any unconfigured package that the package depends on.

conflicts

Permit installation of conflicting packages. Can result in problems from files being overwritten.

depends

Turn dependency problems into warnings.

depends-version

Warn of version problems when checking dependencies, but otherwise ignore.

downgrade

Install even if a newer version is already installed. Forced by default.

hold

Process packages even if they are marked to be held.

not-root

Try to install or remove even when not logged on as root.

overwrite

Overwrite a file from one package with the same file from another package. Forced by default.

overwrite-dir

Overwrite one package's directory with a file from another package.

overwrite-diverted

Overwrite a diverted file with an undiverted version.

remove-essential

Remove an essential package. Note that this can cause your system to stop working.

remove-reinstreq

Remove packages that are broken and are marked to require reinstallation.

-G

Don't install a package if a newer version is already installed. The same as --refuse-downgrade.

--ignore-depends=pkglist

Dependency problems result only in a warning for the packages in pkglist.

--largemem

Specify that dpkg can use as much memory as it needs.

--new

New binary package format. This is a dpkg-deb option.

--no-act

Go through the motions, but don't actually write any changes. Used for testing. Be sure to specify before the action; otherwise changes might be written.

--nocheck

Ignore the contents of the control file when building a package. This is a dpkg-deb option.

-O, --selected-only

Process only packages that are marked as selected for installation.

--old

Old binary package format. This is a dpkg-deb option.

-R, --recursive

Recursively handle .deb files found in the directories specified with -A, --install, --unpack, and --avail and their subdirectories.

-R, --root=dir, --admindir=dir, --instdir=dir

Change default directories. admindir contains administrative files with status and other information about packages; it defaults to /var/lib/dpkg. instdir is the directory in which packages are installed and defaults to /. Changing the root directory to dir automatically changes instdir to dir and admindir to /dir/var/lib/dpkg.

--smallmem

Specify that dpkg should try to preserve memory.

dpkg-deb

dpkg-deb action [options]

Backend command for building and managing Debian package archives. Also see dpkg; you'll often want to use dpkg to pass commands through to dpkg-deb, rather than call dpkg-deb directly.

Actions

-b dir [archive], --build dir [archive]

Create an archive from the filesystem tree starting with directory dir. The directory must have a DEBIAN subdirectory containing the control file and any other control information. If archive is specified and is a filename, the package is written to that file; if no archive is specified, the package is written to dir.deb. If the archive already exists, it is replaced. If archive is the name of a directory, the dpkg-deb looks in the control file for the information it needs to generate the package name. (Note that for this reason, you cannot use --no-check with a directory name.)

-c archive, --contents archive

List the filesystem-tree portion of archive.

-e, --control archive dir

Extract control information from archive into the directory dir, which is created if it doesn't exist.

-f archive [control-fields], --field archive [control-fields]

Extract information about one or more fields in the control file for archive. If no fields are provided, print the entire control file.

-h, --help

Print help information and exit.

-I archive [control-files], --info archive [control-files]

Provide information about binary package archive. If no control files are provided, print a summary of the package contents; otherwise, print the control files in the order they were specified. An error message is printed to standard error for any missing components.

--fsys-tarfile archive

Extract the filesystem tree from archive, and send it to standard output in tar format. Can be used with tar to extract individual files from an archive.

--license

Print the license information and exit. Accepts the spelling --licence in addition to --license.

--version

Print the version number and exit.

-x archive dir, --extract archive dir
-X archive dir, --vextract archive dir

Extract the filesystem tree from archive into the specified directory, creating dir if it doesn't already exist. -x (--extract) works silently, while -X (--vextract) lists the files as it extracts them. Do not use this option to install packages; use dpkg instead.

Options

-D

Turn on debugging.

--new

Build a new-style archive format (this is the default).

--no-check

Don't check the control file before building an archive. This lets you build a broken archive.

--old

Build an old-style archive format.

dpkg-split

dpkg-split [action] [options]

Split a binary package into smaller pieces and reassemble the pieces, manually or in automatic mode. The automatic mode maintains a queue of parts for reassembling. Useful for transferring to and from floppy disks.

Actions

-a -o output part, --auto -o output part

Add part to the queue for automatic reassembly and if all the parts are available, reassemble the package as output.

-d [packages], --discard [packages]

Discard parts from the automatic-assembly queue. If any packages are specified, discard only parts from those packages. Otherwise, empty the queue.

-I parts, --info parts

Print information about the part file or files specified.

-j parts, --join parts

Join the parts of a package file together from the parts specified. The default output file is package-version.deb.

-l, --listq

List the contents of the queue of parts waiting for reassembly, giving the package name, the parts that are on the queue, and the number of bytes.

-s full-package [prefix], --full-package [prefix]

Split the package full-package into parts, named prefixNofM.deb. The prefix defaults to the full-package name without the .deb extension.

-h, --help

Print help message and exit.

--license

Print the license information and exit. Accepts the spelling --licence in addition to --license.

--version

Print the version information and exit.

Options

--depotdir

Specify an alternate directory depotdir for the queue of parts waiting for reassembly. Default is /var/lib/dpkg.

--msdos

Force --split output filenames to be MS-DOS-compatible.

-Q, --npquiet

Do not print an error message for a part that doesn't belong to a binary package when doing automatic queuing or reassembly.

-o output, --output output

Use output as the filename for a reassembled package.

-S num, --partsize num

When splitting, specify the maximum part size (num) in kilobytes. Default is 450 KB.

dselect

dselect [options] [action]

A screen-oriented user frontend to dpkg. The primary user interface for installing and managing packages. See dpkg and dpkg-deb for information on building packages.

Actions

If dselect is run with no action specified on the command line, it displays the following menu:

* 0. [A]ccess      Choose the access method to use.                           
  1. [U]pdate      Update list of available packages, if possible.
  2. [S]elect      Request which packages you want on your system.
  3. [I]nstall     Install and upgrade wanted packages.
  4. [C]onfig      Configure any packages that are unconfigured.
  5. [R]emove      Remove unwanted software.
  6. [Q]uit        Quit dselect.
The asterisk (on the first line here) shows the currently selected option. Any of the menu items can be specified directly on the command line as an action (access, update, select, install, config, remove, quit) to go directly to the desired activity. For example:
% dselect access

If you enter quit on the command line, dselect exits immediately without doing anything. An additional command-line action is menu, which displays the menu and is equivalent to omitting the action.

Options

--admindir dir

Change the directory that holds internal data files to dir. Default is /var/lib/dpkg.

-D [file], --debug [file]

Turn on debugging. Send output to file if specified.

--help

Print help message and exit.

--license

Print the license information and exit. Accepts the spelling --licence in addition to --license.

--version

Print version information and exit.



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