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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | COMMANDS | PACKAGE SELECTIONS MANAGEMENT | EXIT STATUS | ENVIRONMENT | BUGS | SEE ALSO | COLOPHON |
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dselect(1) dpkg suite dselect(1)
dselect - Debian package management frontend
dselect [option...] [command...]
dselect is one of the primary user interfaces for managing
packages on a Debian system. At the dselect main menu, the
system administrator can:
• Update the list of available package versions,
• View the status of installed and available packages,
• Alter package selections and manage dependencies,
• Install new packages or upgrade to newer versions.
dselect operates as a front-end to dpkg(1), the low-level Debian
package handling tool. It features a full-screen package
selections manager with package depends and conflicts resolver.
When run with administrator privileges, packages can be
installed, upgraded and removed. Various access methods can be
configured to retrieve available package version information and
installable packages from package repositories. Depending on the
used access method, these repositories can be public archive
servers on the internet, local archive servers or media discs.
The recommended access method is apt, which is provided by the
package apt(8).
Normally dselect is invoked without parameters. An interactive
menu is presented, offering the user a list of commands. If a
command is given as argument, then that command is started
immediately. Several command line parameters are still available
to modify the running behaviour of dselect or show additional
information about the program.
All options can be specified both on the command line and in the
dselect configuration file /usr/local/etc/dpkg/dselect.cfg or the
files on the configuration directory
/usr/local/etc/dpkg/dselect.cfg.d/. Each line in the
configuration file is either an option (exactly the same as the
command line option but without leading hyphens) or a comment (if
it starts with a ‘#’).
--admindir directory
Changes the directory where the dpkg ‘status’, ‘available’
and similar files are located. Defaults to
/usr/local/var/lib/dpkg if DPKG_ADMINDIR has not been set.
--instdir directory
Set the installation directory, which refers to the directory
where packages get installed (since dpkg 1.21.2). Defaults
to «/» if DPKG_ROOT has not been set.
--root directory
Set the root directory to directory, which sets the
installation directory to «directory» and the administrative
directory to «directory/usr/local/var/lib/dpkg» (since dpkg
1.21.0).
-Dfile, --debug file
Turn on debugging. Debugging information is sent to file.
--expert
Turns on expert mode, i.e. doesn't display possibly annoying
help messages.
--color screenpart:[foreground],[background][:attr[+attr]...]
--colour screenpart:[foreground],[background][:attr[+attr]...]
Configures screen colors. This works only if your display
supports colors. This option may be used multiple times (and
is best used in dselect.cfg). Each use changes the color
(and optionally, other attributes) of one part of the screen.
The parts of the screen (from top to bottom) are:
title
The screen title.
listhead
The header line above the list of packages.
list
The scrolling list of packages (and also some help text).
listsel
The selected item in the list.
pkgstate
In the list of packages, the text indicating the current
state of each package.
pkgstatesel
In the list of packages, the text indicating the current
state of the currently selected package.
infohead
The header line that displays the state of the currently
selected package.
infodesc
The package's short description.
info
Used to display package info such as the package's
description.
infofoot
The last line of the screen when selecting packages.
query
Used to display query lines
helpscreen
Color of help screens.
After the part of the screen comes a colon and the color
specification. You can specify either the foreground color,
the background color, or both, overriding the compiled-in
colors. Use standard curses color names.
Optionally, after the color specification is another colon,
and an attribute specification. This is a list of one or
more attributes, separated by plus (‘+’) characters.
Available attributes include (not all of these will work on
all terminals): normal, standout, underline, reverse, blink,
bright, dim, bold
-?, --help
Print a brief help text and exit successfully.
--version
Print version information and exit successfully.
When dselect is started it can perform the following commands,
either directly if it was specified on the command line or by
prompting the user with a menu of available commands if running
interactively:
access
Choose and configure an access method to access package
repositories.
By default, dselect provides several methods such as media, file
or ftp, but other packages may provide additional methods, for
example the apt access method provided by the apt(8) package.
The use of the apt access method is strongly recommended.
update
Refresh the available packages database.
Retrieves a list of available package versions from the package
repository, configured for the current access method, and update
the dpkg database. The package lists are commonly provided by
the repository as files named Packages or Packages.gz. These
files can be generated by repository maintainers, using the
program dpkg-scanpackages(1).
Details of the update command depend on the access method's
implementation. Normally the process is straightforward and
requires no user interaction.
select
View or manage package selections and dependencies.
This is the main function of dselect. In the select screen, the
user can review a list of all available and installed packages.
When run with administrator privileges, it is also possible to
interactively change packages selection state. dselect tracks
the implications of these changes to other depending or
conflicting packages.
When a conflict or failed depends is detected, a dependency
resolution subscreen is prompted to the user. In this screen, a
list of conflicting or depending packages is shown, and for each
package listed, the reason for its listing is shown. The user
may apply the suggestions proposed by dselect, override them, or
back out all the changes, including the ones that created the
unresolved depends or conflicts.
The use of the interactive package selections management screen
is explained in more detail below.
install
Installs selected packages.
The configured access method will fetch installable or upgradable
packages from the relevant repositories and install these using
dpkg. Depending on the implementation of the access method, all
packages can be prefetched before installation, or fetched when
needed. Some access methods may also remove packages that were
marked for removal.
If an error occurred during install, it is usually advisable to
run install again. In most cases, the problems will disappear or
be solved. If problems persist or the installation performed was
incorrect, please investigate into the causes and circumstances,
and file a bug in the Debian bug tracking system. Instructions
on how to do this can be found at <https://bugs.debian.org/> or
by reading the documentation for bug(1) or reportbug(1), if these
are installed.
Details of the install command depend on the access method's
implementation. The user's attention and input may be required
during installation, configuration or removal of packages. This
depends on the maintainer scripts in the package. Some packages
make use of the debconf(1) library, allowing for more flexible or
even automated installation setups.
config
Configures any previously installed, but not fully configured
packages.
remove
Removes or purges installed packages, that are marked for
removal.
quit
Quit dselect.
Exits the program with zero (successful) error code.
Introduction
dselect directly exposes the administrator to some of the
complexities involved with managing large sets of packages with
many interdependencies. For a user who is unfamiliar with the
concepts and the ways of the Debian package management system, it
can be quite overwhelming. Although dselect is aimed at easing
package management and administration, it is only instrumental in
doing so and cannot be assumed to be a sufficient substitute for
administrator skill and understanding. The user is required to
be familiar with the concepts underlying the Debian packaging
system. In case of doubt, consult the dpkg(1) manual page and
the distribution policy.
Unless dselect is run in expert or immediate mode, a help screen
is first displayed when choosing this command from the menu. The
user is strongly advised to study all of the information
presented in the online help screens, when one pops up. The
online help screens can at any time be invoked with the ‘?’ key.
Screen layout
The select screen is by default split in a top and a bottom half.
The top half shows a list of packages. A cursor bar can select
an individual package, or a group of packages, if applicable, by
selecting the group header. The bottom half of the screen shows
some details about the package currently selected in the top half
of the screen. The type of detail that is displayed can be
varied.
Pressing the ‘I’ key toggles a full-screen display of the
packages list, an enlarged view of the package details, or the
equally split screen.
Package details view
The package details view by default shows the extended package
description for the package that is currently selected in the
packages status list. The type of detail can be toggled by
pressing the ‘i’ key. This alternates between:
• the extended description
• the control information for the installed version
• the control information for the available version
In a dependency resolution screen, there is also the possibility
of viewing the specific unresolved depends or conflicts related
to the package and causing it to be listed.
Packages status list
The main select screen displays a list of all packages known to
the Debian package management system. This includes packages
installed on the system and packages known from the available
packages database.
For every package, the list shows the package's status, priority,
section, installed and available architecture, installed and
available versions, the package name and its short description,
all in one line. By pressing the ‘A’ key, the display of the
installed and available architecture can be toggled between on an
off. By pressing the ‘V’ key, the display of the installed and
available version can be toggled between on an off. By pressing
the ‘v’ key, the package status display is toggled between
verbose and shorthand. Shorthand display is the default.
The shorthand status indication consists of four parts: an error
flag, which should normally be clear, the current status, the
last selection state and the current selection state. The first
two relate to the actual state of the package, the second pair
are about the selections set by the user.
These are the meanings of the shorthand package status indicator
codes:
Error flag:
empty no error
R serious error, needs reinstallation;
Installed state:
empty not installed;
* fully installed and configured;
- not installed but some config files may remain;
U unpacked but not yet configured;
C half-configured (an error happened);
I half-installed (an error happened).
Current and requested selections:
* marked for installation or upgrade;
- marked for removal, configuration files remain;
= on hold: package will not be processed at all;
_ marked for purge, also remove configuration;
n package is new and has yet to be marked.
Cursor and screen movement
The package selection list and the dependency conflict resolution
screens can be navigated using motion commands mapped to the
following keys:
p, Up, k move cursor bar up
n, Down, j move cursor bar down
P, Pgup, Backspace scroll list 1 page up
N, Pgdn, Space scroll list 1 page down
^p scroll list 1 line up
^n scroll list 1 line down
t, Home jump to top of list
e, End jump to end of list
u scroll info 1 page up
d scroll info 1 page down
^u scroll info 1 line up
^d scroll info 1 line down
B, Left-arrow pan display 1/3 screen left
F, Right-arrow pan display 1/3 screen right
^b pan display 1 character left
^f pan display 1 character right
Searching and sorting
The list of packages can be searched by package name. This is
done by pressing ‘/’, and typing a simple search string. The
string is interpreted as a regex(7) regular expression. If you
add ‘/d’ to the search expression, dselect will also search in
descriptions. If you add ‘/i’ the search will be case
insensitive. You may combine these two suffixes like this:
‘/id’. Repeated searching is accomplished by repeatedly pressing
the ‘n’ or ‘\’ keys, until the wanted package is found. If the
search reaches the bottom of the list, it wraps to the top and
continues searching from there.
The list sort order can be varied by pressing the ‘o’ and ‘O’
keys repeatedly. The following nine sort orderings can be
selected:
alphabet
priority+section
section+priority
available
available+priority
available+section
status
status+priority
status+section
Where not listed above explicitly, alphabetic order is used as
the final subordering sort key.
Altering selections
The requested selection state of individual packages may be
altered with the following commands:
+, Insert install or upgrade
=, H hold in present state and version
:, G unhold: upgrade or leave uninstalled
-, Delete remove, but leave configuration
_ remove & purge configuration
When the change request results in one or more unsatisfied
depends or conflicts, dselect prompts the user with a dependency
resolution screen. This will be further explained below.
It is also possible to apply these commands to groups of package
selections, by pointing the cursor bar onto a group header. The
exact grouping of packages is dependent on the current list
ordering settings.
Proper care should be taken when altering large groups of
selections, because this can instantaneously create large numbers
of unresolved depends or conflicts, all of which will be listed
in one dependency resolution screen, making them very hard to
handle. In practice, only hold and unhold operations are useful
when applied to groups.
Resolving depends and conflicts
When the change request results in one or more unsatisfied
depends or conflicts, dselect prompts the user with a dependency
resolution screen. First however, an informative help screen is
displayed.
The top half of this screen lists all the packages that will have
unresolved depends or conflicts, as a result of the requested
change, and all the packages whose installation can resolve any
of these depends or whose removal can resolve any of the
conflicts. The bottom half defaults to show the depends or
conflicts that cause the currently selected package to be listed.
When the sublist of packages is displayed initially, dselect may
have already set the requested selection status of some of the
listed packages, in order to resolve the depends or conflicts
that caused the dependency resolution screen to be displayed.
Usually, it is best to follow up the suggestions made by dselect.
The listed packages' selection state may be reverted to the
original settings, as they were before the unresolved depends or
conflicts were created, by pressing the ‘R’ key. By pressing the
‘D’ key, the automatic suggestions are reset, but the change that
caused the dependency resolution screen to be prompted is kept as
requested. Finally, by pressing ‘U’, the selections are again
set to the automatic suggestion values.
Establishing the requested selections
By pressing enter, the currently displayed set of selections is
accepted. If dselect detects no unresolved depends as a result
of the requested selections, the new selections will be set.
However, if there are any unresolved depends, dselect will again
prompt the user with a dependency resolution screen.
To alter a set of selections that creates unresolved depends or
conflicts and forcing dselect to accept it, press the ‘Q’ key.
This sets the selections as specified by the user,
unconditionally. Generally, don't do this unless you've read the
fine print.
The opposite effect, to back out any selections change requests
and go back to the previous list of selections, is attained by
pressing the ‘X’ or escape keys. By repeatedly pressing these
keys, any possibly detrimental changes to the requested package
selections can be backed out completely to the last established
settings.
If you mistakenly establish some settings and wish to revert all
the selections to what is currently installed on the system,
press the ‘C’ key. This is somewhat similar to using the unhold
command on all packages, but provides a more obvious panic button
in cases where the user pressed enter by accident.
0 The requested command was successfully performed.
2 Fatal or unrecoverable error due to invalid command-line
usage, or interactions with the system, such as accesses to
the database, memory allocations, etc.
DPKG_ROOT
If set and the --instdir or --root options have not been
specified, it will be used as the filesystem root directory
(since dpkg 1.21.0).
DPKG_ADMINDIR
If set and the --admindir or --root option have not been
specified, it will be used as the dpkg database directory
(since dpkg 1.21.0).
HOME
If set, dselect will use it as the directory from which to
read the user specific configuration file.
The dselect package selection interface is confusing to some new
users. Reportedly, it even makes seasoned kernel developers cry.
The documentation is lacking.
There is no help option in the main menu.
The visible list of available packages cannot be reduced.
The built in access methods can no longer stand up to current
quality standards. Use the access method provided by apt(8), it
is not only not broken, it is also much more flexible than the
built in access methods.
dpkg(1), apt(8), sources.list(5), deb(5).
This page is part of the dpkg (Debian Package Manager) project.
Information about the project can be found at
⟨https://wiki.debian.org/Teams/Dpkg/⟩. If you have a bug report
for this manual page, see
⟨http://bugs.debian.org/cgi-bin/pkgreport.cgi?src=dpkg⟩. This
page was obtained from the project's upstream Git repository ⟨git
clone https://git.dpkg.org/git/dpkg/dpkg.git⟩ on 2024-06-14. (At
that time, the date of the most recent commit that was found in
the repository was 2024-05-21.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
1.22.6-77-g86fe7 2024-03-10 dselect(1)
Pages that refer to this page: dpkg(1), dpkg-deb(1), dpkg-name(1), dpkg-scanpackages(1), dselect.cfg(5)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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