The doc-base package implements a flexible mechanism for handling and presenting documentation. The recommended practice is for every Debian package that provides documentation files in any of the file formats enumerated below (other than just manual pages) to register those documents with doc-base by installing a control file via the install-docs script at installation time (and subsequently unregister them again when the package is removed).

Supported file formats

Developers should refer to the documentation that comes with the doc-base package — installed at /usr/share/doc/doc-base/doc-base.html/index.html — for more insight. A condensed version is provided below for convenience.

doc-base clients

There are many clients available in the Debian package repositories to access documentation registered with doc-base. While each provides a unique experience, as a whole they can all be described as well-indexed and requiring a negligible amount of system resources.

dochelp – Utility to browse system documentation
   Written in OCaml
   Developed "in-house" by Debian Developers
   Viewed through a web browser
   Doesn't require a web server
   Index layout is tedious and requires lots of scrolling
   First released in 2014

dwww – Web-based documentation reader
   Written in Perl and C
   Convenient command-line interface
   Viewed through a web browser
   Performs indexing silently in the background
   First released in 1996
   Requires the installation and configuration of a local HTTP server

dhelp – Web-based documentation reader
   Written in Ruby
   Viewed through a web browser
   Performs indexing silently in the background
   Provides fast, full-text searching
   Not-so-convenient command line interface
   First released in 1997

doc-central – Web-based documentation reader
   Written in Python
   Viewed through a web browser
   Performs indexing silently in the background
   Not-so-convenient command line interface
   First released in 2000

yelp – Help browser for GNOME
   Written in JavaScript and C
   Tightly integrated with the GNOME desktop environment
   Some types of documentation served by the others aren't available
   First released in 2002

khelpcenter – Help Center for KDE Plasma
   Written in C++
   Viewed through its own desktop GUI client
   Compact, efficient organization of index and contents
   Instantaneous full-text searching of entire database
   Includes built-in handling of DocBook format
   First released in 2011 with sponsorship from Google

Debian doc-base Manual

ver. 0.11.1, 25 January 2021.
Copyright © 1998, Christian Schwarz <schwarz AT debian DOT org>; 1999–2002, Adam Di Carlo <aph AT debian DOT org>; 2006–2018, Robert Luberda <robert AT debian DOT org>.

This manual is free software; you may redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version.
This is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the GNU General Public License for more details.
A copy of the GNU General Public License is available as /usr/share/common-licenses/GPL in the Debian GNU/Linux distribution or on the World Wide Web at the GNU website. You can also obtain it by writing to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.


This manual describes what doc-base is and how it can be used to manage online manuals on Debian systems.

About doc-base

Some time ago, there was a big discussion on the Debian mailing lists about the preferred documentation format in Debian. The discussion showed clearly that people have very different opinions on that topic and thus, we'll have to implement a flexible solution.

The doc-base package tries to implement such a flexible solution: every Debian package that provides online documentation (other than manual pages) will register these documents to doc-base via the install-docs script at installation time and unregister the manuals again when the package is removed.

Since all manuals will eventually be registered, doc-base can also be used to solve another outstanding problem: Debian currently has four different online documentation systems: doc-central, dwww, dochelp and dhelp. Each system has advantages and disadvantages; thus doc-base supports all of them. The system administrator can choose which implementation he/she prefers.

The packages interface


Each Debian package that installs online manuals (in any format) should register its manuals to doc-base. This is done by installing a doc-base control file (see Control Files) and calling install-docs from the postinst script (see Registering Documents With doc-base).

Document IDs

Each document that is registered to doc-base must have a unique document ID.

The document ID is usually taken from the document's title or from the package name. Here are a few examples:

Document ID



Debian Policy Manual


Debian Developers Reference


Debian doc-base Manual


GNU Emacs Manual

Legal characters for the document ID are lower case letters (a-z), digits (0-9), plus (+) or minus (-) signs and full stops (.), the same characters allowed in package names.

Control Files

For each piece of online documentation, doc-base needs a control file that describes the documentation and the documentation file formats that are provided initially.


Here is an example of a control file:

Document: doc-base
Title: Debian doc-base Manual
Author: Christian Schwarz
Abstract: This manual describes what doc-base is
 and how it can be used to
 manage online manuals on Debian systems.
Section: Debian

Format: DebianDoc-SGML
Files: /usr/share/doc/doc-base/doc-base.sgml.gz

Format: Text
Files: /usr/share/doc/doc-base/doc-base.txt.gz

Format: HTML
Index: /usr/share/doc/doc-base/doc-base.html/index.html
Files: /usr/share/doc/doc-base/doc-base.html/*.html

If the doc-base package provided necessary files in other formats, it would be possible to add more sections at the end of the control file:

Format: PDF
Files: /usr/share/doc-base/doc-base.pdf

Format: PostScript
Files: /usr/share/doc-base/

Format: DVI
Files: /usr/share/doc-base/doc-base.dvi.gz

Format: Info
Index: /usr/share/info/
Files: /usr/share/info/*.gz

Syntax of the control file

As you can see from the above example, the syntax—as is the whole design of doc-base—is heavily influenced by dpkg. This is important, since every maintainer will have to work with doc-base, and thus, it should be simple to remember the basic ideas.

The syntax of the control file is simple:

The main section

The first section of the control file describes the document. The following fields are available:

Document ID, required field; should be the first field.
Title of the document; required field.
Author(s) of the document; optional field.
Short paragraph giving an overview of the document; optional but recommended field.

Section where the document belongs; see The section field. Required field.

Format sections

The next section(s) describe the different formats for the document described in the main section. There must be at least one such section. If there are more, each of them must register files in different formats (e.g. having two Format: HTML sections in a single control file is not allowed). The following fields are available:


Format for the document. Required field. The following formats are recognised (see Supported file formats above): HTML, Text, PDF, PostScript, Info, DVI and DebianDoc-SGML. The values of this field are case-insensitive (e.g. both Text and text are valid).

Index or top-level file for this document format. Only applies to document formats HTML and Info, and required if the format is HTML or Info. This field has to contain the canonical file name of the main page of the document. This file will be specified as the front page link when the document is registered.

Space-delimited list of filenames and/or POSIX shell globs (using *, ?, and [] meta-characters), representing in aggregate the files which constitute the documentation in this format. Required field.

Except for the Info format, the files referred to in both Index and Files fields should be placed somewhere under the /usr/share/doc hierarchy. If for some reason it's not possible, then the registering package should provide a symbolic link pointing from the above hierarchy to the real files and register its documentation through the link, allowing the doc-base, dhelp, or dwww packages to actually handle the documentation. Of course, files in the Info format should be located in the /usr/share/info directory.

The section field

The section field holds a slash-separated list of hierarchical section components. The hierarchy is mostly based on the sections outlined in the Debian Menu Policy, § 2.1. "Preferred menu structure"; however the top-level Applications component was removed, and a few doc-base-specific sections were added.

The full section list is:

Documentation of tools to aid people with disabilities or for machines lacking usual input devices.
Amateur Radio
Anything relating to ham radio.
Data Management
Interactive database programs, collection managers, address books, bibliography tools, etc.
Documentation of Debian specific tools, policies, etc.
Documentation of editors, other than office word processors, for text-based information.
Educational and training software.
Software that allows you to run non-native software or more than one OS at a time.
File Management
Tools for file management, archiving, searching, CD/DVD burning, backup, etc.
Games and recreations. Entries should be placed in the appropriate subsection.
• Games/Action
Games that involve a lot of action and require fast reflexes.
• Games/Adventure
Role playing and adventure games, interactive movies and stories, etc.
• Games/Blocks
Tetris-like games involving falling blocks.
• Games/Board
Games played on a board.
• Games/Card
Games involving a deck of cards.
• Games/Puzzles
Tests of ingenuity and logic.
• Games/Simulation
Simulations of the real world in all detail and complexity.
• Games/Strategy
Games involving long-term strategic thinking.
• Games/Tools
Server browsers, configurators, editors, and other game-related tools that are not games themselves.
• Games/Toys
Amusements, eye-candy, entertaining demos, screen hacks (screen-savers), etc.
2D and 3D graphics manipulation software.
Documentation of programs that provide user documentation.
• Help/Books
• Help/FAQ
Frequently Asked Questions.
• Help/HOWTO
Various HOWTOs.
• Help/RFC
• Help/Standards
Mobile Devices
Software that allows you to interface with mobile devices (phones, PDAs, etc.).
Network related software. This is a two-level section; do not put entries directly here.
• Network/Communication
Mail, USENET news, chat, instant messaging, IP telephony, video conferencing software, etc.
• Network/File Transfer
File transfer software such as download managers, FTP clients, P2P clients, etc.
• Network/Monitoring
Network monitoring software.
• Network/Remote Access
Tools for remotely managing a computer.
• Network/Web Browsing
Web browsers, tools for offline browsing, etc.
• Network/Web News
Web feed (RSS, Atom, etc.) and podcast aggregators.
Office suites, word processors, spreadsheets, CRM, ERP, financial software, etc.

IDEs, debuggers, compilers, APIs, libraries, programming languages. Documentation related to only one specific language should be put in the subsection named like the language, for example:
 • Programming/C
 • Programming/C++
 • Programming/Java
 • Programming/OCaml
 • Programming/Perl
 • Programming/Python
 • Programming/Ruby

Project Management
Timetable managers, group task trackers, bug tracking software, etc.
Documentation of scientific and engineering-related software. Please use the appropriate subsection.
• Science/Astronomy
Astronomy-related software.
• Science/Biology
Biology-related software.
• Science/Chemistry
Chemistry-related software.
• Science/Data Analysis
Software designed for processing, extracting, and presenting generic scientific data.
• Science/Electronics
Circuit design tools, simulators and assemblers for microprocessors, etc.
• Science/Engineering
CAD, UML tools, diagram-drawing and other engineering-related software.
• Science/Geoscience
Geoscience-related software.
• Science/Mathematics
Mathematics-related software.
• Science/Medicine
Medicine-related software.
• Science/Physics
Physics-related software.
• Science/Social
Social sciences-related software.
Programs that affect the whole screen.
• Screen/Saving
Tools for blanking the screen. Entries of screen hacks and configuration GUIs should go to other appropriate sections.
• Screen/Locking
Tools for locking the screen.
Various shells to be used inside a terminal emulator.
Sound players, editors, and rippers/recorders.
System related software. Place entries in one of the subsections.
• System/Administration
Administrative and system configuration utilities, also tools for personal user settings.
• System/Hardware
Tools for manipulating specific hardware, especially non-standard laptop hardware.
• System/Language Environment
This section is reserved for language-env as a special case.
• System/Monitoring
System information and monitoring tools, log viewers, etc.
• System/Package Management
Package managers and related tools.
• System/Security
Security, cryptography and privacy related software, antiviruses, tools to track and report bugs, etc.
Terminal Emulators
Graphical terminal emulators.
Text oriented tools like dictionaries, OCR, translation, text analysis software, etc.
TV and Radio
TV-in, TV-out, FM radio, teletext browsers, etc.
Software for typesetting text and graphics from structured input files like LaTeX or docbook sources, database exports etc.
Software for viewing images, documents and other (non-video) media.
Video players, editors, and rippers/recorders.
Web Development
Software for web site editing, web programming, and site administration.
Window Managers
X window managers.

Registering Documents With doc-base

In order to register a piece of online documentation to doc-base, all the package needs to do is install the control file (see Control Files) as file /usr/share/doc-base/document-id.

Further processing of the control file is handled by a dpkg trigger (cf. /usr/share/doc/dpkg/triggers.txt.gz) provided by doc-base. The trigger will call install-docs to generate the /var/lib/doc-base/documents/<document-id> file and register the online manuals to dwww and dhelp, when the package is installed, and unregister the manuals when the package is removed.

doc-base 0.8.x features and incompatibilities

Splitting control files over multiple binary packages

Since version 0.8.7, it is possible to provide documents with the same document-id by more than one binary package. All such documents will be merged together and the merged document will be generated in the /var/lib/doc-base/documents/<document-id> file. This feature can be useful in cases when the same documentation, but in different formats, is provided by two binary packages.

For example the foo-text package could install the /usr/share/doc-base/foo-text file with the following contents:

Document: foo
Title: This is foo
Author: John Foo <>
Abstract: Description of foo
Section: Text

Format: text
Files: /usr/share/foo-text/foo.txt.gz

and the foo-html package could install the following /usr/share/doc-base/foo-html file:

Document: foo
Title: This is foo
Author: John Foo <>
Abstract: Description of foo
Section: Text

Format: HTML
Index: /usr/share/foo-html/index.html
Files: /usr/share/foo-html/*.html

When both packages are installed, install-docs will merge the contents of the two files into /var/lib/doc-base/documents/foo:

Document: foo
Title: This is foo
Author: John Foo <>
Abstract: Description of foo
Section: Text

Format: HTML
Index: /usr/share/foo-html/index.html
Files: /usr/share/foo-html/*.html

Format: text
Files: /usr/share/foo-text/foo.txt.gz

Registering local documents

Version 0.8.7 and further allow a user to register local documentation. In order to do this, local administrators need to create their own control file (see Control Files), place it in the /etc/doc-base/documents directory, and then register it with install-docs -i /etc/doc-base/documents/<document-id>.

Before removing the file, it should be de-registered with install-docs -r /etc/doc-base/documents/<document-id>.

Since version 0.8.12, install-docs --install-changed may be used instead of the two above commands.

dpkg triggers

doc-base 0.8.11 and greater use the dpkg triggers feature to register and unregister the documentation. There is no longer a need to call install-docs from maintainer scripts.

Checking syntax of control files

With the new -c / --check option of install-docs, it is possible to check the control file:

$ install-docs --check /usr/share/doc-base/doc-base
 /usr/share/doc-base/doc-base: No problems found

$ install-docs -c /usr/share/doc-base/xlogmaster
 Error in `/usr/share/doc-base/xlogmaster', line 15: `Index' value missing for format info
  /usr/share/doc-base/xlogmaster: Fatal error found, the file won't be registered

$ install-docs -c /usr/share/doc-base/MC-FAQ /usr/share/doc-base/gnu-privacy-handbook
 /usr/share/doc-base/MC-FAQ: 1 warning(s) or non-fatal error(s) found
 /usr/share/doc-base/gnu-privacy-handbook: 1 warning(s) or non-fatal error(s) found

More details about the warnings and non-fatal errors can be found using the -v / --verbose option:

$ install-docs -v -c /usr/share/doc-base/MC-FAQ /usr/share/doc-base/gnu-privacy-handbook
 Warning in `/usr/share/doc-base/MC-FAQ', line 1: invalid value of `Document' field
  /usr/share/doc-base/MC-FAQ: 1 warning(s) or non-fatal error(s) found
 Warning in `/usr/share/doc-base/gnu-privacy-handbook', line 12: file
  /usr/share/doc/gnupg-doc/GNU_Privacy_Handbook/html/book1.html' does not exist
  /usr/share/doc-base/gnu-privacy-handbook: 1 warning(s) or non-fatal error(s) found

With the --rootdir option, it is possible to check non-installed packages:

$ dpkg-deb -x autoclass_3.3.4-6_i386.deb AUTOCLASS_UNPACKED
$ install-docs --rootdir AUTOCLASS_UNPACKED -vc AUTOCLASS_UNPACKED/usr/share/doc-base/*
 AUTOCLASS_UNPACKED/usr/share/doc-base/autoclass-results: No problems found
 AUTOCLASS_UNPACKED/usr/share/doc-base/autoclass-theory: No problems found

If the --rootdir option was omitted, install-docs would complain:

Warning in `AUTOCLASS_UNPACKED/usr/share/doc-base/autoclass-results', line 20: file mask '/usr/share/doc/autoclass/kdd-95.pdf' does not match any files
Warning in `AUTOCLASS_UNPACKED/usr/share/doc-base/autoclass-theory', line 20: file mask '/usr/share/doc/autoclass/tr-fia-90-12-7-01.pdf' does not match any files

Getting information about installed documents

If you want to get information about the status of an installed manual, you can use the -s / --status option of install-docs, followed by the document id:

$ install-docs -s foo
 Document: foo
 Abstract: This manual is about foos, bars, and Debian.
 Author: Wile E. Coyote
 Section: Debian
 Title: Debian Foo's Manual

 Format: debiandoc-sgml
 Files: /usr/share/doc/foo/sgml/foo.sgml.gz

 Format: html
 Files: /usr/share/doc/foo/html-sgml/*.html
 Index: /usr/share/doc/foo/html-sgml/index.html

 Control-Files: /usr/share/doc-base/foo (changed: Tue Apr  8 23:09:24 2008)

doc-base always creates a /var/lib/doc-base/documents/<document-id> file when installing a document.

See also