Debian Live Manual Debian Live Project <debian-live@lists.debian.org>

Rights: Copyright: Copyright (C) 2006-2015 Live Systems Project, Copyright (C) 2016-2026 The Debian Live team
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# Debian Live Manual

# Über Live Systeme

# Über dieses Handbuch

#### 1. Über dieses Handbuch

##### 1.1 Für die Ungeduldigen

##### 1.2 Begriffe

##### 1.3 Autoren

##### 1.4 Contributing to this document

###### 1.4.1 Applying changes

###### 1.4.2 Translation

# About the Debian Live Project

#### 2. About the Debian Live Project

##### 2.1 Motivation

###### 2.1.1 What is wrong with current live systems

###### 2.1.2 Why create our own live system?

##### 2.2 Philosophy

###### 2.2.1 Only unchanged packages from Debian "main" and "non-free-firmware"

###### 2.2.2 No package configuration of the live system

##### 2.3 Contact

# Benutzer

# Installation

#### 3. Installation

##### 3.1 Requirements

##### 3.2 Installing live-build

###### 3.2.1 From the Debian repository

###### 3.2.2 From source

##### 3.3 Installing live-boot and live-config

###### 3.3.1 From the Debian repository

###### 3.3.2 From source

# The basics

#### 4. The basics

##### 4.1 What is a live system?

##### 4.2 Downloading prebuilt images

##### 4.3 First steps: building an ISO hybrid image

##### 4.4 Using an ISO hybrid live image

###### 4.4.1 Burning an ISO image to a physical medium

###### 4.4.2 Copying an ISO hybrid image to a USB stick

###### 4.4.3 Using the space left on a USB stick

###### 4.4.4 Booting the live medium

##### 4.5 Using a virtual machine for testing

###### 4.5.1 Testing an ISO image with QEMU

###### 4.5.2 Testing an ISO image with VirtualBox

##### 4.6 Building and using an HDD image

##### 4.7 Building a netboot image

###### 4.7.1 DHCP server

###### 4.7.2 TFTP server

###### 4.7.3 NFS server

###### 4.7.4 Netboot testing HowTo

###### 4.7.5 Qemu

##### 4.8 Webbooting

###### 4.8.1 Getting the webboot files

###### 4.8.2 Booting webboot images

# Overview of tools

#### 5. Overview of tools

##### 5.1 The live-build package

###### 5.1.1 The `lb config` command

###### 5.1.2 The `lb build` command

###### 5.1.3 The `lb clean` command

##### 5.2 The live-boot package

##### 5.3 The live-config package

# Managing a configuration

#### 6. Managing a configuration

##### 6.1 Dealing with configuration changes

###### 6.1.1 Why use auto scripts? What do they do?

###### 6.1.2 Use example auto scripts

##### 6.2 Clone a configuration published via Git

# Customizing contents

#### 7. Customization overview

##### 7.1 Build time vs. boot time configuration

##### 7.2 Stages of the build

##### 7.3 Supplement lb config with files

##### 7.4 Customization tasks

# Customizing package installation

#### 8. Customizing package installation

##### 8.1 Package sources

###### 8.1.1 Distribution, archive areas and mode

###### 8.1.2 Distribution mirrors

###### 8.1.3 Distribution mirrors used at build time

###### 8.1.4 Distribution mirrors used at run time

###### 8.1.5 Additional repositories

##### 8.2 Choosing packages to install

###### 8.2.1 Package lists

###### 8.2.2 Using metapackages

###### 8.2.3 Local package lists

###### 8.2.4 Local binary package lists

###### 8.2.5 Generated package lists

###### 8.2.6 Using conditionals inside package lists

###### 8.2.7 Removing packages at install time

###### 8.2.8 Summary

###### 8.2.9 Desktop and language tasks

###### 8.2.10 Kernel flavour and version

###### 8.2.11 Custom kernels

##### 8.3 Installing modified or third-party packages

###### 8.3.1 Using `packages.chroot` to install custom packages

###### 8.3.2 Using an APT repository to install custom packages

###### 8.3.3 Custom packages and APT

##### 8.4 Configuring APT at build time

###### 8.4.1 Choosing apt or aptitude

###### 8.4.2 Using a proxy with APT

###### 8.4.3 Tweaking APT to save space

###### 8.4.4 Passing options to apt or aptitude

###### 8.4.5 APT pinning

# Customizing contents

#### 9. Customizing contents

##### 9.1 Includes

###### 9.1.1 Live/chroot local includes

###### 9.1.2 Binary local includes

##### 9.2 Hooks

###### 9.2.1 Chroot local hooks

###### 9.2.2 Binary local hooks

###### 9.2.3 Boot-time hooks

##### 9.3 Preseeding Debconf questions

# Customizing run time behaviours

#### 10. Customizing run time behaviours

##### 10.1 Customizing the live user

##### 10.2 Customizing locale and language

##### 10.3 Persistence

###### 10.3.1 The persistence.conf file

###### 10.3.2 Using more than one persistence store

###### 10.3.3 Using persistence with encryption

# Customizing the binary image

#### 11. Customizing the binary image

##### 11.1 Bootloaders

##### 11.2 ISO metadata

# Customizing Debian Installer

#### 12. Customizing Debian Installer

##### 12.1 Types of Debian Installer

##### 12.2 Customizing Debian Installer by preseeding

##### 12.3 Customizing Debian Installer content

# Projekt

# Contributing to the project

#### 13. Contributing to the project

##### 13.1 Translation of man pages

# Reporting bugs

#### 14. Reporting bugs

##### 14.1 Known issues

##### 14.2 Do the research

##### 14.3 Rebuild from scratch

##### 14.4 Use up-to-date packages

##### 14.5 Collect information

##### 14.6 Isolate the failing case if possible

##### 14.7 Use the correct package to report the bug against

###### 14.7.1 At build time while bootstrapping

###### 14.7.2 At build time while installing packages

###### 14.7.3 At boot time

###### 14.7.4 At run time

##### 14.8 Where to report bugs

# Coding Style

#### 15. Coding Style

##### 15.1 Compatibility

##### 15.2 Indenting

##### 15.3 Wrapping

##### 15.4 Variables

##### 15.5 Miscellaneous

# Beispiele

#### 16. Examples

##### 16.1 Using the examples

##### 16.2 Tutorial 1: A default image

##### 16.3 Tutorial 2: A web browser utility

##### 16.4 Tutorial 3: A personalized image

###### 16.4.1 First revision

###### 16.4.2 Second revision

##### 16.5 A VNC Kiosk Client

##### 16.6 A minimal image for a 512MB USB key

##### 16.7 A localized GNOME desktop and installer

# Anhang

# Style guide

#### 17. Style guide

##### 17.1 Guidelines for authors

###### 17.1.1 Linguistic features

###### 17.1.2 Procedures

##### 17.2 Guidelines for translators

###### 17.2.1 Translation hints

1

# Debian Live Manual

2

# Über Live Systeme

3

# Über dieses Handbuch

4

#### 1. Über dieses Handbuch

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This manual serves as a single access point to all documentation related to the Debian Live Project and in particular applies to the software produced by the project for the Debian "bookworm" release. An up-to-date version can always be found at ‹https://live-team.pages.debian.net/live-manual/›

6

While live-manual is primarily focused on helping you build a live system and not on end-user topics, an end user may find some useful information in these sections: The Basics covers downloading prebuilt images and preparing images to be booted from media or the network, either using the web builder or running live-build directly on your system. Customizing run time behaviours describes some options that may be specified at the boot prompt, such as selecting a keyboard layout and locale, and using persistence.

7

Einige der erwähnten Befehle im Text müssen als Superuser ausgeführt werden. Dies kann entweder dadurch erreicht werden, indem zuerst auf den root Benutzer gewechselt wird mittels `su` oder durch die Benutzung von `sudo`. Um die Befehle welche als unprivilegierter Benutzer ausgeführt werden können und diesen welche Superuser Rechte benötigen, sind den Befehlen `$` respektive `#` vorangestellt. Dieses Symbol ist nicht Teil des Befehls.

8

##### 1.1 Für die Ungeduldigen

9

Obowhl wir denken dass alles in diesem Handbuch mehr oder weniger für die einen oder anderen Benutzer wichtig ist, sind wir uns bewusst, dass es sich um viel Material handelt. Für ein schnelles Erfolgserlebnis in der Anwendung dieser Software schlagen wir die folgende Reihenfolge vor, bevor sie sich mit den Details befassen:

10

First, read this chapter, About this manual, from the beginning and ending with the Terms section. Next, skip to the three tutorials at the front of the Examples section designed to teach you image building and customization basics. Read Using the examples first, followed by Tutorial 1: A default image, Tutorial 2: A web browser utility and finally Tutorial 3: A personalized image. By the end of these tutorials, you will have a taste of what can be done with live systems.

11

We encourage you to return to more in-depth study of the manual, perhaps next reading The basics, skimming or skipping Building a netboot image, and finishing by reading the Customization overview and the chapters that follow it. By this point, we hope you are thoroughly excited by what can be done with live systems and motivated to read the rest of the manual, cover-to-cover.

12

##### 1.2 Begriffe

13

- Live system: An operating system that can boot without installation to a hard drive. Live systems do not alter local operating system(s) or file(s) already installed on the computer hard drive unless instructed to do so. Live systems are typically booted from media such as CDs, DVDs or USB sticks. Some may also boot over the network (via netboot images, see Building a netboot image), and over the Internet (via the boot parameter `fetch=URL`, see Webbooting).

14

- Live medium: As distinct from live system, the live medium refers to the CD, DVD or USB stick where the binary produced by live-build and used to boot the live system is written. More broadly, the term also refers to any place where this binary resides for the purposes of booting the live system, such as the location for the network boot files.

15

- Debian Live Project: The project which maintains, among others, the live-boot, live-build, live-config, live-tools and live-manual packages.

16

- Host system: The environment used to create the live system.

17

- Target system: The environment used to run the live system.

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- live-boot: A collection of scripts used to boot live systems.

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- live-build: A collection of scripts used to build customized live systems.

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- live-config: A collection of scripts used to configure a live system during the boot process.

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- live-tools: A collection of additional scripts used to perform useful tasks within a running live system.

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- live-manual: This document is maintained in a package called live-manual.

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- Debian Installer (d-i): The official installation system for the Debian distribution.

24

- Boot parameters: Parameters that can be entered at the bootloader prompt to influence the kernel or live-config.

25

- chroot: The chroot program, `chroot(8)`, enables us to run different instances of the GNU/Linux environment on a single system simultaneously without rebooting.

26

- Binary image: A file containing the live system, such as live-image-amd64.hybrid.iso or live-image-amd64.img.

27

- Target distribution: The distribution upon which your live system will be based. This can differ from the distribution of your host system.

28

- stable/testing/unstable: The stable distribution, currently codenamed bookworm, contains the latest officially released distribution of Debian. The testing distribution, temporarily codenamed trixie, is the staging area for the next stable release. A major advantage of using this distribution is that it has more recent versions of software relative to the stable release. The unstable distribution, permanently codenamed sid, is where active development of Debian occurs. Generally, this distribution is run by developers and those who like to live on the edge. Throughout the manual, we tend to use codenames for the releases, such as trixie or sid, as that is what is supported by the tools themselves.

29

##### 1.3 Autoren

30

Liste der Autoren (in alphabetischer Reihenfolge):

31

- Ben Armstrong

32

- Brendan Sleight

33

- Carlos Zuferri

34

- Chris Lamb

35

- Daniel Baumann

36

- Franklin Piat

37

- Jonas Stein

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- Kai Hendry

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- Marco Amadori

40

- Mathieu Geli

41

- Matthias Kirschner

42

- Richard Nelson

43

- Roland Clobus

44

- Trent W. Buck

45

##### 1.4 Contributing to this document

46

This manual is intended as a community project and all proposals for improvements and contributions are extremely welcome. Please see the section Contributing to the project for detailed information on how to fetch the commit key and make good commits.

47

###### 1.4.1 Applying changes

48

In order to make changes to the English manual you have to edit the right files in `manual/en/` but prior to the submission of your contribution, please preview your work. To preview the live-manual, ensure the packages needed for building it are installed by executing:

49

# apt-get install make po4a ruby ruby-nokogiri sisu-complete

50

You may build the live-manual from the top level directory of your Git checkout by executing:

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$ make build

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Since it takes a while to build the manual in all supported languages, authors may find it convenient to use one of the fast proofing shortcuts when reviewing the new documentation they have added to the English manual. Using `PROOF=1` builds live-manual in html format, but without the segmented html files, and using `PROOF=2` builds live-manual in pdf format, but only the A4 and letter portraits. That is why using either of the `PROOF=` possibilities can save up a considerable amount of time, e.g:

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$ make build PROOF=1

54

When proofing one of the translations it is possible to build only one language by executing, e.g:

55

$ make build LANGUAGES=de

56

It is also possible to build by document type, e.g:

57

$ make build FORMATS=pdf

58

Or combine both, e.g:

59

$ make build LANGUAGES=de FORMATS=html

60

After revising your work and making sure that everything is fine, do not use `make commit` unless you are updating translations in the commit, and in that case, do not mix changes to the English manual and translations in the same commit, but use separate commits for each. See the Translation section for more details.

61

###### 1.4.2 Translation

62

Note: For the translation of the man pages see Translation of man pages

63

In order to translate live-manual, follow these steps depending on whether you are starting a translation from scratch or continue working on an already existing one:

64

- Start a new translation from scratch

65

- Translate the about_manual.ssi.pot, about_project.ssi.pot and index.html.in.pot files in `manual/pot/` to your language with your favourite editor (such as poedit) and send the translated `.po` files to the mailing list to check their integrity. live-manual's integrity check not only ensures that the `.po` files are 100% translated but it also detects possible errors.

66

- Once checked, to enable a new language in the autobuild it is enough to add the initial translated files to `manual/po/${LANGUAGE}/` and edit `manual/_sisu/home/index.html` adding the name of the language and its name in English between brackets. And then, add the folder `manual/${LANGUAGE}/` to the file `.gitignore`. Finally, run `make commit`.

67

- Continue with an already started translation

68

- If your target language has already been added, you can randomly continue translating the remaining .po files in `manual/po/${LANGUAGE}/` using your favourite editor (such as poedit) .

69

- Do not forget that you need to run `make commit` to ensure that the translated manuals are updated from the .po files and then you can review your changes launching `make build` before `git add .`, `git commit -m "Translating..."` and `git push`. Remember that since `make build` can take a considerable amount of time, you can proofread languages individually as explained in Applying changes

70

After running `make commit` you will see some text scroll by. These are basically informative messages about the processing status and also some hints about what can be done in order to improve live-manual. Unless you see a fatal error, you usually can proceed and submit your contribution.

71

live-manual comes with two utilities that can greatly help translators to find untranslated and changed strings. The first one is "make translate". It launches an script that tells you in detail how many untranslated strings there are in each .po file. The second one, the "make fixfuzzy" target, only acts upon changed strings but it helps you to find and fix them one by one.

72

Keep in mind that even though these utilities might be really helpful to do translation work on the command line, the use of an specialized tool like poedit is the recommended way to do the task. It is also a good idea to read the Debian localization (l10n) documentation and, specifically to live-manual, the Guidelines for translators.

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Note: You can use `make clean` to clean your git tree before pushing. This step is not compulsory thanks to the .gitignore file but it is a good practice to avoid committing files involuntarily.

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# About the Debian Live Project

75

#### 2. About the Debian Live Project

76

##### 2.1 Motivation

77

###### 2.1.1 What is wrong with current live systems

78

When Debian Live Project was initiated (around 2006), there were already several Debian based live systems available and they are doing a great job. From the Debian perspective most of them have one or more of the following disadvantages:

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- They are not Debian projects and therefore lack support from within Debian.

80

- They mix different distributions, e.g. testing and unstable.

81

- They support i386 only.

82

- They modify the behaviour and/or appearance of packages by stripping them down to save space.

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- They include packages from outside of the Debian archive.

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- They ship custom kernels with additional patches that are not part of Debian.

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- They are large and slow due to their sheer size and thus not suitable for rescue issues.

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- They are not available in different flavours, e.g. CDs, DVDs, USB-stick and netboot images.

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###### 2.1.2 Why create our own live system?

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Debian is the Universal Operating System: Debian has a live system to show around and to accurately represent the Debian system with the following main advantages:

89

- It is a subproject of Debian.

90

- It reflects the (current) state of one distribution.

91

- It runs on as many architectures as possible.

92

- It consists of unchanged Debian packages only.

93

- It does not contain any packages that are not in the Debian archive.

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- It uses an unaltered Debian kernel with no additional patches.

95

##### 2.2 Philosophy

96

###### 2.2.1 Only unchanged packages from Debian "main" and "non-free-firmware"

97

We will only use packages from the Debian repository in the "main" section. The non-free section is not part of Debian and therefore cannot be used for official live system images.

98

Starting with Debian 12 bookworm we added the "non-free-firmware" section for better support of modern hardware.

99

We will not change any packages. Whenever we need to change something, we will do that in coordination with its package maintainer in Debian.

100

As an exception, our own packages such as live-boot, live-build or live-config may temporarily be used from our own repository for development reasons (e.g. to create development snapshots). They will be uploaded to Debian on a regular basis.

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###### 2.2.2 No package configuration of the live system

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In this phase we will not ship or install sample or alternative configurations. All packages are used in their default configuration as they are after a regular installation of Debian.

103

Whenever we need a different default configuration, we will do that in coordination with its package maintainer in Debian.

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A system for configuring packages is provided using debconf allowing custom configured packages to be installed in your custom produced live system images, but for the prebuilt live images we choose to leave packages in their default configuration, unless absolutely necessary in order to work in the live environment. Wherever possible, we prefer to adapt packages within the Debian archive to work better in a live system versus making changes to the live toolchain or prebuilt image configurations. For more information, please see Customization overview.

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##### 2.3 Contact

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- Mailing list: The primary contact for the project is the mailing list at ‹https://lists.debian.org/debian-live/›. You can email the list directly by addressing your mail to ‹debian-live@lists.debian.org›​. The list archives are available at ‹https://lists.debian.org/debian-live/›.

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- IRC: A number of users and developers are present in the #debian-live channel on irc.debian.org (OFTC). When asking a question on IRC, please be patient for an answer. If no answer is forthcoming, please email the mailing list.

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- BTS : The Debian Bug Tracking System (BTS) contains details of bugs reported by users and developers. Each bug is given a number, and is kept on file until it is marked as having been dealt with. For more information, please see Reporting bugs.

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# Benutzer

110

# Installation

111

#### 3. Installation

112

##### 3.1 Requirements

113

Building live system images has very few system requirements for the host system:

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- Superuser (root) access

115

- An up-to-date version of live-build

116

- A POSIX-compliant shell, such as bash or dash

117

- debootstrap

118

- Linux 2.6 or newer

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- A mount point with dev and exec rights.

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# mount <your_mount_point> -odev,exec,remount

121

Note that using Debian or a Debian-derived distribution is not required - live-build will run on almost any distribution with the above requirements.

122

##### 3.2 Installing live-build

123

You can install live-build in a number of different ways:

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- From the Debian repository

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- From source

126

- From snapshots

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If you are using Debian, the recommended way is to install live-build via the Debian repository.

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###### 3.2.1 From the Debian repository

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Simply install live-build like any other package:

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# apt-get install live-build

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###### 3.2.2 From source

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live-build is developed using the Git version control system. On Debian based systems, this is provided by the git package. To check out the latest code, execute:

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$ git clone https://salsa.debian.org/live-team/live-build.git

134

You can build and install your own Debian package by executing:

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$ cd live-build
$ dpkg-buildpackage -b -uc -us
$ cd ..

136

Now install whichever of the freshly built `.deb` files you were interested in, e.g.

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# dpkg -i live-build_4.0-1_all.deb

138

You can also install live-build directly to your system by executing:

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# make install

140

and uninstall it with:

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# make uninstall

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##### 3.3 Installing live-boot and live-config

143

Note: You do not need to install live-boot or live-config on your system to create customized live systems. However, doing so will do no harm and is useful for reference purposes. If you only want the documentation, you may now install the live-boot-doc and live-config-doc packages separately.

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###### 3.3.1 From the Debian repository

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Both live-boot and live-config are available from the Debian repository as per Installing live-build.

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###### 3.3.2 From source

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To use the latest source from git, you can follow the process below. Please ensure you are familiar with the terms mentioned in Terms.

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- Checkout the live-boot and live-config sources

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$ git clone https://salsa.debian.org/live-team/live-boot.git
$ git clone https://salsa.debian.org/live-team/live-config.git

150

Consult the live-boot and live-config man pages for details on customizing if that is your reason for building these packages from source.

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- Build live-boot and live-config .deb files

152

You must build either on your target distribution or in a chroot containing your target platform: this means if your target is trixie then you should build against trixie.

153

Use a personal builder such as pbuilder or sbuild if you need to build live-boot for a target distribution that differs from your build system. For example, for trixie live images, build live-boot in a trixie chroot. If your target distribution happens to match your build system distribution, you may build directly on the build system using `dpkg-buildpackage` (provided by the dpkg-dev package):

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$ cd live-boot
$ dpkg-buildpackage -b -uc -us
$ cd ../live-config
$ dpkg-buildpackage -b -uc -us

155

- Use applicable generated .deb files

156

As live-boot and live-config are installed by live-build system, installing the packages in the host system is not sufficient: you should treat the generated .deb files like any other custom packages. Since your purpose for building from source is likely to test new things over the short term before the official release, follow Installing modified or third-party packages to temporarily include the relevant files in your configuration. In particular, notice that both packages are divided into a generic part, a documentation part and one or more back-ends. Include the generic part, only one back-end matching your configuration, and optionally the documentation. Assuming you are building a live image in the current directory and have generated all .deb files for a single version of both packages in the directory above, these bash commands would copy all of the relevant packages including default back-ends:

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$ cp ../live-boot{_,-initramfs-tools,-doc}*.deb config/packages.chroot/
$ cp ../live-config{_,-sysvinit,-doc}*.deb config/packages.chroot/

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# The basics

159

#### 4. The basics

160

This chapter contains a brief overview of the build process and instructions for using the three most commonly used image types. The most versatile image type, `iso-hybrid`, may be used on a virtual machine, optical medium or USB portable storage device. In certain special cases, as explained later, the `hdd` type may be more suitable. The chapter includes detailed instructions for building and using a `netboot` type image, which is a bit more involved due to the setup required on the server. This is an slightly advanced topic for anyone who is not already familiar with netbooting, but it is included here because once the setup is done, it is a very convenient way to test and deploy images for booting on the local network without the hassle of dealing with image media.

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The section finishes with a quick introduction to webbooting which is, perhaps, the easiest way of using different images for different purposes, switching from one to the other as needed using the internet as a means.

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Throughout the chapter, we will often refer to the default filenames produced by live-build. If you are downloading a prebuilt image instead, the actual filenames may vary.

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##### 4.1 What is a live system?

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A live system usually means an operating system booted on a computer from a removable medium, such as a CD-ROM or USB stick, or from a network, ready to use without any installation on the usual drive(s), with auto-configuration done at run time (see Terms).

165

With live systems, it's an operating system, built for one of the supported architectures (currently amd64 and arm64). It is made from the following parts:

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- Linux kernel image, usually named `vmlinuz*`

167

- Initial RAM disk image (initrd): a RAM disk set up for the Linux boot, containing modules possibly needed to mount the System image and some scripts to do it.

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- System image: The operating system's filesystem image. Usually, a SquashFS compressed filesystem is used to minimize the live system image size. Note that it is read-only. So, during boot the live system will use a RAM disk and 'union' mechanism to enable writing files within the running system. However, all modifications will be lost upon shutdown unless optional persistence is used (see Persistence).

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- Bootloader: A small piece of code crafted to boot from the chosen medium, possibly presenting a prompt or menu to allow selection of options/configuration. It loads the Linux kernel and its initrd to run with an associated system filesystem. Different solutions can be used, depending on the target medium and format of the filesystem containing the previously mentioned components: isolinux to boot from a CD or DVD in ISO9660 format, syslinux for HDD or USB drive booting from a VFAT partition, extlinux for ext2/3/4 and btrfs partitions, pxelinux for PXE netboot, GRUB for ext2/3/4 partitions, etc.

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You can use live-build to build the system image from your specifications, set up a Linux kernel, its initrd, and a bootloader to run them, all in one medium-dependent format (ISO9660 image, disk image, etc.).

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##### 4.2 Downloading prebuilt images

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You can download one of the prebuilt images from ‹https://www.debian.org/CD/live/›. For many of the popular desktop environments (GNOME, Xfce, KDE, etc.) a specific live image is prepared.

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If you are unsure which file to download, use the 'Live GNOME' image from the 'stable' release. You can then skip reading the next sections and run the image in a virtual machine.

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##### 4.3 First steps: building an ISO hybrid image

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Regardless of the image type, you will need to perform the same basic steps to build an image each time. As a first example, create a build directory, change to that directory and then execute the following sequence of live-build commands to create a basic ISO hybrid image containing a default live system without X.org. It is suitable for burning to CD or DVD media, and also to copy onto a USB stick.

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The name of the working directory is absolutely up to you, but if you take a look at the examples used throughout live-manual, it is a good idea to use a name that helps you identify the image you are working with in each directory, especially if you are working or experimenting with different image types. In this case you are going to build a default system so let's call it, for example, live-default.

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$ mkdir live-default && cd live-default

178

Then, run the `lb config` command. This will create a "config/" hierarchy in the current directory for use by other commands:

179

$ lb config

180

No parameters are passed to these commands, so defaults for all of their various options will be used. See The lb config command for more details.

181

Now that the "config/" hierarchy exists, build the image with the `lb build` command:

182

# lb build

183

This process can take a while, depending on the speed of your computer and your network connection. When it is complete, there should be a `live-image-amd64.hybrid.iso` image file, ready to use, in the current directory.

184

Note: If you are building on an amd64 system the name of the resulting image will be `live-image-amd64.hybrid.iso`. Keep in mind this naming convention throughout the manual.

185

##### 4.4 Using an ISO hybrid live image

186

After either building or downloading an ISO hybrid image the usual next step is to prepare your medium for booting, either CD-R(W) or DVD-R(W) optical media or a USB stick.

187

###### 4.4.1 Burning an ISO image to a physical medium

188

Burning an ISO image is easy. Just install xorriso and use it from the command-line to burn the image. For instance:

189

# apt-get install xorriso
$ xorriso -as cdrecord -v dev=/dev/sr0 blank=as_needed live-image-amd64.hybrid.iso

190

###### 4.4.2 Copying an ISO hybrid image to a USB stick

191

ISO images prepared with `xorriso`, can be simply copied to a USB stick with the `cp` program or an equivalent. Plug in a USB stick with a size large enough for your image file and determine which device it is, which we hereafter refer to as `${USBSTICK}`. This is the device file of your key, such as `/dev/sdb`, not a partition, such as `/dev/sdb1`! You can find the right device name by looking in `dmesg`'s output after plugging in the stick, or better yet, `ls -l /dev/disk/by-id`.

192

Once you are certain you have the correct device name, use the `cp` command to copy the image to the stick. This will definitely overwrite any previous contents on your stick!

193

$ cp live-image-amd64.hybrid.iso ${USBSTICK}
$ sync

194

Note: The sync command is useful to ensure that all the data, which is stored in memory by the kernel while copying the image, is written to the USB stick.

195

###### 4.4.3 Using the space left on a USB stick

196

After copying the `live-image-amd64.hybrid.iso` to a USB stick, the first partition on the device will be filled up by the live system. To use the remaining free space, use a partitioning tool such as gparted or parted to create a new partition on the stick.

197

# gparted ${USBSTICK}

198

After the partition is created, where `${PARTITION}` is the name of the partition, such as `/dev/sdb2`, you have to create a filesystem on it. One possible choice would be ext4.

199

# mkfs.ext4 ${PARTITION}

200

Note: If you want to use the extra space with Windows, apparently that OS cannot normally access any partitions but the first. Some solutions to this problem have been discussed on our mailing list, but it seems there are no easy answers.

201

Remember: Every time you install a new live-image-amd64.hybrid.iso on the stick, all data on the stick will be lost because the partition table is overwritten by the contents of the image, so back up your extra partition first to restore again after updating the live image.

202

###### 4.4.4 Booting the live medium

203

The first time you boot your live medium, whether CD, DVD, USB key, or PXE boot, some setup in your computer's BIOS may be needed first. Since BIOSes vary greatly in features and key bindings, we cannot get into the topic in depth here. Some BIOSes provide a key to bring up a menu of boot devices at boot time, which is the easiest way if it is available on your system. Otherwise, you need to enter the BIOS configuration menu and change the boot order to place the boot device for the live system before your normal boot device.

204

Once you've booted the medium, you are presented with a boot menu. If you just press enter here, the system will boot using the default entry, `Live` and default options. For more information about boot options, see the "help" entry in the menu and also the live-boot and live-config man pages found within the live system.

205

Assuming you've selected `Live` and booted a default desktop live image, after the boot messages scroll by, you should be automatically logged into the `user` account and see a desktop, ready to use. If you have booted a console-only image, you should be automatically logged in on the console to the `user` account and see a shell prompt, ready to use.

206

##### 4.5 Using a virtual machine for testing

207

It can be a great time-saver for the development of live images to run them in a virtual machine (VM). This is not without its caveats:

208

- Running a VM requires enough RAM for both the guest OS and the host and a CPU with hardware support for virtualization is recommended.

209

- There are some inherent limitations to running on a VM, e.g. poor video performance, limited choice of emulated hardware.

210

- When developing for specific hardware, there is no substitute for running on the hardware itself.

211

- Occasionally there are bugs that relate only to running in a VM. When in doubt, test your image directly on the hardware.

212

Provided you can work within these constraints, survey the available VM software and choose one that is suitable for your needs.

213

###### 4.5.1 Testing an ISO image with QEMU

214

The most versatile VM in Debian is QEMU. If your processor has hardware support for virtualization, use the qemu-kvm package; the qemu-kvm package description briefly lists the requirements.

215

First, install qemu-kvm if your processor supports it. If not, install qemu, in which case the program name is `qemu` instead of `kvm` in the following examples. The qemu-utils package is also valuable for creating virtual disk images with `qemu-img`.

216

# apt-get install qemu-kvm qemu-utils

217

Booting an ISO image is simple:

218

$ kvm -cdrom live-image-amd64.hybrid.iso -m 4G

219

See the man pages for more details.

220

Note: For live systems containing a desktop environment that you want to test with qemu, you may wish to include the spice-vdagent package in your live-build configuration. This will automatically adjust the resolution and enable the clipboard between the virtual machine and the host.

221

$ echo "spice-vdagent" >> config/package-lists/spice.list.chroot

222

###### 4.5.2 Testing an ISO image with VirtualBox

223

In order to test the ISO with virtualbox:

224

# apt-get install virtualbox virtualbox-qt virtualbox-dkms
$ virtualbox

225

Create a new virtual machine, change the storage settings to use `live-image-amd64.hybrid.iso` as the CD/DVD device, and start the machine.

226

Note: For live systems containing X.org that you want to test with virtualbox, you may wish to include the VirtualBox X.org driver package, virtualbox-guest-dkms and virtualbox-guest-x11, in your live-build configuration. Otherwise, the resolution is limited to 800x600.

227

$ echo "virtualbox-guest-dkms virtualbox-guest-x11" >> config/package-lists/my.list.chroot

228

In order to make the dkms package work, also the kernel headers for the kernel flavour used in your image need to be installed. Instead of manually listing the correct linux-headers package in above created package list, the selection of the right package can be done automatically by live-build.

229

$ lb config --linux-packages "linux-image linux-headers"

230

##### 4.6 Building and using an HDD image

231

Building an HDD image is similar to an ISO hybrid one in all respects except you specify `-b hdd` and the resulting filename is `live-image-amd64.img` which cannot be burnt to optical media. It is suitable for booting from USB sticks, USB hard drives, and various other portable storage devices. Normally, an ISO hybrid image can be used for this purpose instead, but if you have a BIOS which does not handle hybrid images properly, you need an HDD image.

232

Note: if you created an ISO hybrid image with the previous example, you will need to clean up your working directory with the `lb clean` command (see The lb clean command):

233

# lb clean --binary

234

Run the `lb config` command as before, except this time specifying the HDD image type:

235

$ lb config -b hdd

236

Now build the image with the `lb build` command:

237

# lb build

238

When the build finishes, a `live-image-amd64.img` file should be present in the current directory.

239

The generated binary image contains a VFAT partition and the syslinux bootloader, ready to be directly written on a USB device. Once again, using an HDD image is just like using an ISO hybrid one on USB. Follow the instructions in Using an ISO hybrid live image, except use the filename `live-image-amd64.img` instead of `live-image-amd64.hybrid.iso`.

240

Likewise, to test an HDD image with Qemu, install qemu as described above in Testing an ISO image with QEMU. Then run `kvm` or `qemu`, depending on which version your host system needs, specifying `live-image-amd64.img` as the first hard drive.

241

$ kvm -hda live-image-amd64.img

242

##### 4.7 Building a netboot image

243

The following sequence of commands will create a basic netboot image containing a default live system without X.org. It is suitable for booting over the network.

244

Note: if you performed any previous examples, you will need to clean up your working directory with the `lb clean` command:

245

# lb clean

246

In this specific case, a `lb clean --binary` would not be enough to clean up the necessary stages. The cause for this is that in netboot setups, a different initramfs configuration needs to be used which live-build performs automatically when building netboot images. Since the initramfs creation belongs to the chroot stage, switching to netboot in an existing build directory means to rebuild the chroot stage too. Therefore, `lb clean` (which will remove the chroot stage, too) needs to be used.

247

Run the `lb config` command as follows to configure your image for netbooting:

248

$ lb config -b netboot --net-root-path "/srv/debian-live" --net-root-server "192.168.0.2"

249

In contrast with the ISO and HDD images, netbooting does not, itself, serve the filesystem image to the client, so the files must be served via NFS. Different network filesystems can be chosen through lb config. The `--net-root-path` and `--net-root-server` options specify the location and server, respectively, of the NFS server where the filesystem image will be located at boot time. Make sure these are set to suitable values for your network and server.

250

Now build the image with the `lb build` command:

251

# lb build

252

In a network boot, the client runs a small piece of software which usually resides on the EPROM of the Ethernet card. This program sends a DHCP request to get an IP address and information about what to do next. Typically, the next step is getting a higher level bootloader via the TFTP protocol. That could be pxelinux, GRUB, or even boot directly to an operating system like Linux.

253

For example, if you unpack the generated `live-image-amd64.netboot.tar` archive in the `/srv/debian-live` directory, you'll find the filesystem image in `live/filesystem.squashfs` and the kernel, initrd and pxelinux bootloader in `tftpboot/`.

254

We must now configure three services on the server to enable netbooting: the DHCP server, the TFTP server and the NFS server.

255

###### 4.7.1 DHCP server

256

We must configure our network's DHCP server to be sure to give an IP address to the netbooting client system, and to advertise the location of the PXE bootloader.

257

Here is an example for inspiration, written for the ISC DHCP server `isc-dhcp-server` in the `/etc/dhcp/dhcpd.conf` configuration file:

258

# /etc/dhcp/dhcpd.conf - configuration file for isc-dhcp-server
ddns-update-style none;
option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;
default-lease-time 600;
max-lease-time 7200;
log-facility local7;
subnet 192.168.0.0 netmask 255.255.255.0 {
range 192.168.0.1 192.168.0.254;
filename "pxelinux.0";
next-server 192.168.0.2;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.0.255;
option routers 192.168.0.1;
}

259

###### 4.7.2 TFTP server

260

This serves the kernel and initial ramdisk to the system at run time.

261

You should install the tftpd-hpa package. It can serve all files contained inside a root directory, usually `/srv/tftp`. To let it serve files inside `/srv/debian-live/tftpboot`, run as root the following command:

262

# dpkg-reconfigure -plow tftpd-hpa

263

and fill in the new tftp server directory when being asked about it.

264

###### 4.7.3 NFS server

265

Once the guest computer has downloaded and booted a Linux kernel and loaded its initrd, it will try to mount the Live filesystem image through a NFS server.

266

You need to install the nfs-kernel-server package.

267

Then, make the filesystem image available through NFS by adding a line like the following to `/etc/exports`:

268

/srv/debian-live *(ro,async,no_root_squash,no_subtree_check)

269

and tell the NFS server about this new export with the following command:

270

# exportfs -rv

271

Setting up these three services can be a little tricky. You might need some patience to get all of them working together. For more information, see the syslinux wiki at ‹https://wiki.syslinux.org/wiki/index.php?title=PXELINUX› or the Debian Installer Manual's TFTP Net Booting section at ‹https://www.debian.org/releases/stable/amd64/ch04s05.en.html›. They might help, as their processes are very similar.

272

###### 4.7.4 Netboot testing HowTo

273

Netboot image creation is made easy with live-build, but testing the images on physical machines can be really time consuming.

274

To make our life easier, we can use virtualization.

275

###### 4.7.5 Qemu

276

- Install qemu, bridge-utils, sudo.

277

Edit `/etc/qemu-ifup`:

278

#!/bin/sh
sudo -p "Password for $0:" /sbin/ifconfig $1 172.20.0.1
echo "Executing /etc/qemu-ifup"
echo "Bringing up $1 for bridged mode..."
sudo /sbin/ifconfig $1 0.0.0.0 promisc up
echo "Adding $1 to br0..."
sudo /usr/sbin/brctl addif br0 $1
sleep 2

279

Get, or build a `grub-floppy-netboot`.

280

Launch `qemu` with "`-net nic,vlan=0 -net tap,vlan=0,ifname=tun0`"

281

##### 4.8 Webbooting

282

Webbooting is a convenient way of retrieving and booting live systems using the internet as a means. The requirements for webbooting are very few. On the one hand, you need a medium with a bootloader, an initial ramdisk and a kernel. On the other hand, a web server to store the squashfs files which contain the filesystem.

283

###### 4.8.1 Getting the webboot files

284

As usual, you can build the images yourself or use the prebuilt files. Using prebuilt images would be handy for doing initial testing until one can fine tune their own needs. If you have built a live image you will find the files needed for webbooting in the build directory under `binary/live/`. The files are called `vmlinuz`, `initrd.img` and `filesystem.squashfs`.

285

It is also possible to extract those files from an already existing iso image. In order to achieve that, loopback mount the image as follows:

286

# mount -o loop image.iso /mnt

287

The files are to be found under the `live/` directory. In this specific case, it would be `/mnt/live/`. This method has the disadvantage that you need to be root to be able to mount the image. However, it has the advantage that it is easily scriptable and thus, easily automated.

288

But undoubtedly, the easiest way of extracting the files from an iso image and uploading it to the web server at the same time, is using the midnight commander or mc. If you have the genisoimage package installed, the two-pane file manager allows you to browse the contents of an iso file in one pane and upload the files via ftp in the other pane. Even though this method requires manual work, it does not require root privileges.

289

###### 4.8.2 Booting webboot images

290

While some users will prefer virtualization to test webbooting, we refer to real hardware here to match the following possible use case which should only be considered as an example.

291

In order to boot a webboot image it is enough to have the components mentioned above, i.e. `vmlinuz` and `initrd.img` in a usb stick inside a directory named `live/` and install syslinux as bootloader. Then boot from the usb stick and type `fetch=URL/PATH/TO/FILE` at the boot options. live-boot will retrieve the squashfs file and store it into ram. This way, it is possible to use the downloaded compressed filesystem as a regular live system. For example:

292

append boot=live components fetch=http://192.168.2.50/images/webboot/filesystem.squashfs

293

Use case: You have a web server in which you have stored two squashfs files, one which contains a full desktop, like for example gnome, and a standard one. If you need a graphical environment for one machine, you can plug your usb stick in and webboot the gnome image. If you need one of the tools included in the second type of image, perhaps for another machine, you can webboot the standard one.

294

# Overview of tools

295

#### 5. Overview of tools

296

This chapter contains an overview of the three main tools used in building live systems: live-build, live-boot and live-config.

297

##### 5.1 The live-build package

298

live-build is a collection of scripts to build live systems. These scripts are also referred to as "commands".

299

The idea behind live-build is to be a framework that uses a configuration directory to completely automate and customize all aspects of building a Live image.

300

Many concepts are similar to those used to build Debian packages with debhelper:

301

- The scripts have a central location for configuring their operation. In debhelper, this is the `debian/` subdirectory of a package tree. For example, dh_install will look, among others, for a file called `debian/install` to determine which files should exist in a particular binary package. In much the same way, live-build stores its configuration entirely under a `config/` subdirectory.

302

- The scripts are independent - that is to say, it is always safe to run each command.

303

Unlike debhelper, live-build provides the tools to generate a skeleton configuration directory. This could be considered to be similar to tools such as dh-make. For more information about these tools, read on, since the remainder of this section discuses the four most important commands. Note that the preceding `lb` is a generic wrapper for live-build commands.

304

- lb config: Responsible for initializing a Live system configuration directory. See The lb config command for more information.

305

- lb build: Responsible for starting a Live system build. See The lb build command for more information.

306

- lb clean: Responsible for removing parts of a Live system build. See The lb clean command for more information.

307

###### 5.1.1 The `lb config` command

308

As discussed in live-build, the scripts that make up live-build read their configuration with the `source` command from a single directory named `config/`. As constructing this directory by hand would be time-consuming and error-prone, the `lb config` command can be used to create the initial skeleton configuration tree.

309

Issuing `lb config` without any arguments creates the `config/` subdirectory which is populated with some default settings in configuration files, and two skeleton trees named `auto/` and `local/`.

310

$ lb config
[2025-02-15 12:34:56] lb config
P: Using http proxy: http://127.0.0.1:3142
P: Creating config tree for a debian/testing/amd64 system
P: Symlinking hooks...

311

Using `lb config` without any arguments would be suitable for users who need a very basic image, or who intend to provide a more complete configuration via `auto/config` later (see Managing a configuration for details).

312

Normally, you will want to specify some options. For example, to specify which package manager to use while building the image:

313

$ lb config --apt aptitude

314

It is possible to specify many options, such as:

315

$ lb config --binary-images netboot --bootappend-live "boot=live components hostname=live-host username=live-user" ...

316

A full list of options is available in the `lb_config` man page.

317

###### 5.1.2 The `lb build` command

318

The `lb build` command reads in your configuration from the `config/` directory. It then runs the lower level commands needed to build your Live system.

319

###### 5.1.3 The `lb clean` command

320

It is the job of the `lb clean` command to remove various parts of a build so subsequent builds can start from a clean state. By default, `chroot`, `binary` and `source` stages are cleaned, but the cache is left intact. Also, individual stages can be cleaned. For example, if you have made changes that only affect the binary stage, use `lb clean --binary` prior to building a new binary. If your changes invalidate the bootstrap and/or package caches, e.g. changes to `--mode`, `--architecture`, or `--bootstrap`, you must use `lb clean --purge`. See the `lb_clean` man page for a full list of options.

321

##### 5.2 The live-boot package

322

live-boot is a collection of scripts providing hooks for the initramfs-tools, used to generate an initramfs capable of booting live systems, such as those created by live-build. This includes the live system ISOs, netboot tarballs, and USB stick images.

323

At boot time it will look for read-only media containing a `/live/` directory where a root filesystem (often a compressed filesystem image like squashfs) is stored. If found, it will create a writable environment, using OverlayFS, for Debian like systems to boot from.

324

More information on initial ramfs in Debian can be found in the Debian Linux Kernel Handbook at ‹https://kernel-team.pages.debian.net/kernel-handbook/› in the chapter on initramfs.

325

##### 5.3 The live-config package

326

live-config consists of the scripts that run at boot time after live-boot to configure the live system automatically. It handles such tasks as setting the hostname, locales and timezone, creating the live user, inhibiting cron jobs and performing autologin of the live user.

327

# Managing a configuration

328

#### 6. Managing a configuration

329

This chapter explains how to manage a live configuration from initial creation, through successive revisions and successive releases of both the live-build software and the live image itself.

330

##### 6.1 Dealing with configuration changes

331

Live configurations rarely are perfect on the first try. It may be fine to pass `lb config` options from the command-line to perform a single build, but it is more typical to revise those options and build again until you are satisfied. To support these changes, you will need auto scripts which ensure your configuration is kept in a consistent state.

332

###### 6.1.1 Why use auto scripts? What do they do?

333

The `lb config` command stores the options you pass to it in `config/*` files along with many other options set to default values. If you run `lb config` again, it will not reset any option that was defaulted based on your initial options. So, for example, if you run `lb config` again with a new value for `--binary-images`, any dependent options that were defaulted for the old image type may no longer work with the new ones. Nor are these files intended to be read or edited. They store values for over a hundred options, so nobody, let alone yourself, will be able to see in these which options you actually specified. And finally, if you run `lb config`, then upgrade live-build and it happens to rename an option, `config/*` would still contain variables named after the old option that are no longer valid.

334

For all these reasons, `auto/*` scripts will make your life easier. They are simple wrappers to the `lb config`, `lb build` and `lb clean` commands that are designed to help you manage your configuration. The `auto/config` script stores your `lb config` command with all desired options, the `auto/clean` script removes the files containing configuration variable values, and the `auto/build` script keeps a `build.log` of each build. Each of these scripts is run automatically every time you run the corresponding `lb` command. By using these scripts, your configuration is easier to read and is kept internally consistent from one revision to the next. Also, it will be much easier for you identify and fix options which need to change when you upgrade live-build after reading the updated documentation.

335

###### 6.1.2 Use example auto scripts

336

For your convenience, live-build comes with example auto shell scripts to copy and edit. Start a new, default configuration, then copy the examples into it:

337

$ mkdir mylive && cd mylive && lb config
$ mkdir auto
$ cp /usr/share/doc/live-build/examples/auto/* auto/

338

Edit `auto/config`, adding any options as you see fit. For instance:

339

#!/bin/sh
lb config noauto \
--distribution stable \
--binary-images hdd \
--mirror-bootstrap http://ftp.ch.debian.org/debian/ \
--mirror-binary http://ftp.ch.debian.org/debian/ \
"${@}"

340

Now, each time you use `lb config`, `auto/config` will reset the configuration based on these options. When you want to make changes to them, edit the options in this file instead of passing them to `lb config`. When you use `lb clean`, `auto/clean` will clean up the `config/*` files along with any other build products. And finally, when you use `lb build`, a log of the build will be written by `auto/build` in `build.log`.

341

Note: A special `noauto` parameter is used here to suppress another call to `auto/config`, thereby preventing infinite recursion. Make sure you don't accidentally remove it when making edits. Also, take care to ensure when you split the `lb config` command across multiple lines for readability, as shown in the example above, that you don't forget the backslash (\) at the end of each line that continues to the next.

342

##### 6.2 Clone a configuration published via Git

343

Use the `lb config --config` option to clone a Git repository that contains a live system configuration. If you would like to base your configuration on one maintained by the Debian Live Project, look at ‹https://salsa.debian.org/live-team/› for the repository named `live-images` in the category `Subgroups and projects`. This repository contains the configurations for the live systems prebuilt images.

344

For example, to build a standard image, use the `live-images` repository as follows:

345

$ mkdir live-images && cd live-images
$ lb config --config https://salsa.debian.org/live-team/live-images.git::debian
$ cd images/standard

346

Edit `auto/config` and any other things you need in the `config` tree to suit your needs. For example, the unofficial non-free prebuilt images are made by simply adding `--archive-areas "main contrib non-free"`.

347

You may optionally define a shortcut in your Git configuration by adding the following to your `${HOME}/.gitconfig`:

348

[url "https://salsa.debian.org/live-team/"]
insteadOf = lso:

349

This enables you to use `lso:` anywhere you need to specify the address of a `salsa.debian.org` git repository. If you also drop the optional `.git` suffix, starting a new image using this configuration is as easy as:

350

$ lb config --config lso:live-images::debian

351

Cloning the entire `live-images` repository pulls the configurations used for several images. If you feel like building a different image after you have finished with the first one, change to another directory and again and optionally, make any changes to suit your needs.

352

In any case, remember that every time you will have to build the image as superuser: `lb build`

353

# Customizing contents

354

#### 7. Customization overview

355

This chapter gives an overview of the various ways in which you may customize a live system.

356

##### 7.1 Build time vs. boot time configuration

357

Live system configuration options are divided into build-time options which are options that are applied at build time and boot-time options which are applied at boot time. Boot-time options are further divided into those occurring early in the boot, applied by the live-boot package, and those that happen later in the boot, applied by live-config. Any boot-time option may be modified by the user by specifying it at the boot prompt. The image may also be built with default boot parameters so users can normally just boot directly to the live system without specifying any options when all of the defaults are suitable. In particular, the argument to `lb --bootappend-live` consists of any default kernel command line options for the Live system, such as persistence, keyboard layouts, or timezone. See Customizing locale and language, for example.

358

Build-time configuration options are described in the `lb config` man page. Boot-time options are described in the man pages for live-boot and live-config. Although the live-boot and live-config packages are installed within the live system you are building, it is recommended that you also install them on your build system for easy reference when you are working on your configuration. It is safe to do so, as none of the scripts contained within them are executed unless the system is configured as a live system.

359

##### 7.2 Stages of the build

360

The build process is divided into stages, with various customizations applied in sequence in each. The first stage to run is the bootstrap stage. This is the initial phase of populating the chroot directory with packages to make a barebones Debian system. This is followed by the chroot stage, which completes the construction of chroot directory, populating it with all of the packages listed in the configuration, along with any other materials. Most customization of content occurs in this stage. The final stage of preparing the live image is the binary stage, which builds a bootable image, using the contents of the chroot directory to construct the root filesystem for the Live system, and including the installer and any other additional material on the target medium outside of the Live system's filesystem. After the live image is built, if enabled, the source tarball is built in the source stage.

361

Within each of these stages, there is a particular sequence in which commands are applied. These are arranged in such a way as to ensure customizations can be layered in a reasonable fashion. For example, within the chroot stage, preseeds are applied before any packages are installed, packages are installed before any locally included files are copied, and hooks are run later, after all of the materials are in place.

362

##### 7.3 Supplement lb config with files

363

Although `lb config` creates a skeletal configuration in the `config/` directory, to accomplish your goals, you may need to provide additional files in subdirectories of `config/`. Depending on where the files are stored in the configuration, they may be copied into the live system's filesystem or into the binary image filesystem, or may provide build-time configurations of the system that would be cumbersome to pass as command-line options. You may include things such as custom lists of packages, custom artwork, or hook scripts to run either at build time or at boot time, boosting the already considerable flexibility of debian-live with code of your own.

364

##### 7.4 Customization tasks

365

The following chapters are organized by the kinds of customization task users typically perform: Customizing package installation, Customizing contents and Customizing locale and language cover just a few of the things you might want to do.

366

# Customizing package installation

367

#### 8. Customizing package installation

368

Perhaps the most basic customization of a live system is the selection of packages to be included in the image. This chapter guides you through the various build-time options to customize live-build's installation of packages. The broadest choices influencing which packages are available to install in the image are the distribution and archive areas. To ensure decent download speeds, you should choose a nearby distribution mirror. You can also add your own repositories for backports, experimental or custom packages, or include packages directly as files. You can define lists of packages, including metapackages which will install many related packages at once, such as packages for a particular desktop or language. Finally, a number of options give some control over apt, or if you prefer, aptitude, at build time when packages are installed. You may find these handy if you use a proxy, want to disable installation of recommended packages to save space, or need to control which versions of packages are installed via APT pinning, to name a few possibilities.

369

##### 8.1 Package sources

370

###### 8.1.1 Distribution, archive areas and mode

371

The distribution you choose has the broadest impact on which packages are available to include in your live image. Specify the codename, which defaults to testing. Any current distribution carried in the archive may be specified by its codename here. (See Terms for more details.) The `--distribution` option not only influences the source of packages within the archive, but also instructs live-build to enable other sources.

372

For example, to build against the stable release, with security, updates (enabled per default) and additionally proposed-updates and backports, specify:

373

$ lb config --distribution stable --proposed-updates true --backports true

374

Similarly, for the unstable release, sid, which has neither security nor updates, specify:

375

$ lb config --distribution sid

376

Within the distribution archive, archive areas are major divisions of the archive. In Debian, these are `main`, `contrib` and `non-free`. Only `main` contains software that is part of the Debian distribution, hence that is the default. One or more values may be specified, e.g.

377

$ lb config --archive-areas "main contrib non-free"

378

Experimental support is available for some Debian derivatives through a `--mode` option. By default, this option is set to `debian` only if you are building on a Debian or on an unknown system. If `lb config` is invoked on any of the supported derivatives, it will default to create an image of that derivative. If `lb config` is run in e.g. `ubuntu` mode, the distribution names and archive areas for the specified derivative are supported instead of the ones for Debian. The mode also modifies live-build behaviour to suit the derivatives.

379

Note: The projects for whom these modes were added are primarily responsible for supporting users of these options. The Debian Live Project, in turn, provides development support on a best-effort basis only, based on feedback from the derivative projects as we do not develop or support these derivatives ourselves.

380

###### 8.1.2 Distribution mirrors

381

The Debian archive is replicated across a large network of mirrors around the world so that people in each region can choose a nearby mirror for best download speed. Each of the `--mirror-*` options governs which distribution mirror is used at various stages of the build. Recall from Stages of the build that the bootstrap stage is when the chroot is initially populated by debootstrap with a minimal system, and the chroot stage is when the chroot used to construct the live system's filesystem is built. Thus, the corresponding mirror switches are used for those stages, and later, in the binary stage, the `--mirror-binary` and `--mirror-binary-security` values are used, superseding any mirrors used in an earlier stage.

382

###### 8.1.3 Distribution mirrors used at build time

383

To set the distribution mirrors used at build time to point at a local mirror, it is sufficient to set `--mirror-bootstrap` and `--mirror-chroot-security` as follows.

384

$ lb config --mirror-bootstrap http://localhost/debian/ \
--mirror-chroot-security http://localhost/debian-security/

385

The chroot mirror, specified by `--mirror-chroot`, defaults to the `--mirror-bootstrap` value.

386

###### 8.1.4 Distribution mirrors used at run time

387

The `--mirror-binary*` options govern the distribution mirrors placed in the binary image. These may be used to install additional packages while running the live system. The defaults employ `deb.debian.org`, a service that chooses a geographically close mirror based, among other things, on the user's IP family and the availability of the mirrors. This is a suitable choice when you cannot predict which mirror will be best for all of your users. Or you may specify your own values as shown in the example below. An image built from this configuration would only be suitable for users on a network where "`mirror`" is reachable.

388

$ lb config --mirror-binary http://mirror/debian/ \
--mirror-binary-security http://mirror/debian-security/ \
--mirror-binary-backports http://mirror/debian-backports/

389

###### 8.1.5 Additional repositories

390

You may add more repositories, broadening your package choices beyond what is available in your target distribution. These may be, for example, for backports, experimental or custom packages. To configure additional repositories, create `config/archives/your-repository.list.chroot`, and/or `config/archives/your-repository.list.binary` files. As with the `--mirror-*` options, these govern the repositories used in the chroot stage when building the image, and in the binary stage, i.e. for use when running the live system.

391

For example, `config/archives/live.list.chroot` allows you to install packages from the debian-live snapshot repository at live system build time.

392

deb http://debian-live.alioth.debian.org/ sid-snapshots main contrib non-free

393

If you add the same line to `config/archives/live.list.binary`, the repository will be added to your live system's `/etc/apt/sources.list.d/` directory.

394

If such files exist, they will be picked up automatically.

395

You should also put the ASCII-armored GPG key used to sign the repository into `config/archives/your-repository.key.{binary,chroot}` files.

396

Should you need custom APT pinning, such APT preferences snippets can be placed in `config/archives/your-repository.pref.{binary,chroot}` files and will be automatically added to your live system's `/etc/apt/preferences.d/` directory.

397

Similarly, if you need custom APT_AUTH.CONF(5) authentication configuration, this can be placed in `config/archives/your-repository.auth.{binary,chroot}` files and will be automatically added to your live system's `/etc/apt/auth.conf.d/` directory

398

##### 8.2 Choosing packages to install

399

There are a number of ways to choose which packages live-build will install in your image, covering a variety of different needs. You can simply name individual packages to install in a package list. You can also use metapackages in those lists, or select them using package control file fields. And finally, you may place package files in your `config/` tree, which is well suited to testing of new or experimental packages before they are available from a repository.

400

###### 8.2.1 Package lists

401

Package lists are a powerful way of expressing which packages should be installed. The list syntax supports conditional sections which makes it easy to build lists and adapt them for use in multiple configurations. Package names may also be injected into the list using shell helpers at build time.

402

Note: The behaviour of live-build when specifying a package that does not exist is determined by your choice of APT utility. See Choosing apt or aptitude for more details.

403

###### 8.2.2 Using metapackages

404

The simplest way to populate your package list is to use a task metapackage maintained by your distribution. For example:

405

$ lb config
$ echo task-gnome-desktop > config/package-lists/desktop.list.chroot

406

This supersedes the older predefined list method supported in `live-build` 2.x. Unlike predefined lists, task metapackages are not specific to the Live System project. Instead, they are maintained by specialist working groups within the distribution and therefore reflect the consensus of each group about which packages best serve the needs of the intended users. They also cover a much broader range of use cases than the predefined lists they replace.

407

All task metapackages are prefixed `task-`, so a quick way to determine which are available (though it may contain a handful of false hits that match the name but aren't metapackages) is to match on the package name with:

408

$ apt-cache search --names-only ^task-

409

In addition to these, you will find other metapackages with various purposes. Some are subsets of broader task packages, like `gnome-core`, while others are individual specialized parts of a Debian Pure Blend, such as the `education-*` metapackages. To list all metapackages in the archive, install the `debtags` package and list all packages with the `role::metapackage` tag as follows:

410

$ debtags search role::metapackage

411

###### 8.2.3 Local package lists

412

Whether you list metapackages, individual packages, or a combination of both, all local package lists are stored in `config/package-lists/`. Since more than one list can be used, this lends itself well to modular designs. For example, you may decide to devote one list to a particular choice of desktop, another to a collection of related packages that might as easily be used on top of a different desktop. This allows you to experiment with different combinations of sets of packages with a minimum of fuss, sharing common lists between different live image projects.

413

Package lists that exist in this directory need to have a `.list` suffix in order to be processed, and then an additional stage suffix, `.chroot` or `.binary` to indicate which stage the list is for.

414

The packages in the `.list.chroot_install` list are present both in the live system and in the installed system.

415

Note: If you don't specify the stage suffix, the list will be used for both stages. Normally, you want to specify `.list.chroot` so that the packages will only be installed in the live filesystem and not have an extra copy of the `.deb` placed on the medium.

416

###### 8.2.4 Local binary package lists

417

To make a binary stage list, place a file suffixed with `.list.binary` in `config/package-lists/`. These packages are not installed in the live filesystem, but are included on the live medium under `pool/`. You would typically use such a list with one of the non-live installer variants. As mentioned above, if you want this list to be the same as your chroot stage list, simply use the `.list` suffix by itself.

418

###### 8.2.5 Generated package lists

419

It sometimes happens that the best way to compose a list is to generate it with a script. Any line starting with an exclamation point indicates a command to be executed within the chroot when the image is built. For example, one might include the line `! grep-aptavail -n -sPackage -FPriority standard | sort` in a package list to produce a sorted list of available packages with `Priority: standard`.

420

In fact, selecting packages with the `grep-aptavail` command (from the `dctrl-tools` package) is so useful that `live-build` provides a `Packages` helper script as a convenience. This script takes two arguments: `field` and `pattern`. Thus, you can create a list with the following contents:

421

$ lb config
$ echo '! Packages Priority standard' > config/package-lists/standard.list.chroot

422

###### 8.2.6 Using conditionals inside package lists

423

Any of the live-build configuration variables stored in `config/*` (minus the `LB_` prefix) may be used in conditional statements in package lists. Generally, this means any `lb config` option uppercased and with dashes changed to underscores. But in practice, it is only the ones that influence package selection that make sense, such as `DISTRIBUTION`, `ARCHITECTURES` or `ARCHIVE_AREAS`.

424

For example, to install `ia32-libs` if the `--architectures amd64` is specified:

425

#if ARCHITECTURES amd64
ia32-libs
#endif

426

You may test for any one of a number of values, e.g. to install memtest86+ if either `--architectures i386` or `--architectures amd64` is specified:

427

#if ARCHITECTURES i386 amd64
memtest86+
#endif

428

You may also test against variables that may contain more than one value, e.g. to install vrms if either `contrib` or `non-free` is specified via `--archive-areas`:

429

#if ARCHIVE_AREAS contrib non-free
vrms
#endif

430

The nesting of conditionals is not supported.

431

###### 8.2.7 Removing packages at install time

432

You can list packages in files with `.list.chroot_live` and `.list.chroot_install` suffixes inside the `config/package-lists` directory. If both a live and an install list exist, the packages in the `.list.chroot_live` list are removed with a hook after the installation (if the user uses the installer). The packages in the `.list.chroot_install` list are present both in the live system and in the installed system. This is a special tweak for the installer and may be useful if you have `--debian-installer live` set in your config, and wish to remove live system-specific packages at install time.

433

###### 8.2.8 Summary

434

The table below shows which configuration files are required to achieve the desired availability of the package.

435

| X.chroot | X.chroot_live | X | X.binary
--- | --- | --- | --- | ---
Package is installed in the live system | Yes | Yes | Yes | No
Package is removed after installing the live system | No | Yes | No | N/A
Package can be installed from the live system without network | N/A | N/A | Yes *1 | Yes

436

*1: Because the installer needs this package

437

`X` = `config/package-lists/custom_name.list`

438

###### 8.2.9 Desktop and language tasks

439

Desktop and language tasks are special cases that need some extra planning and configuration. Live images are different from Debian Installer images in this respect. In the Debian Installer, if the medium was prepared for a particular desktop environment flavour, the corresponding task will be automatically installed. Thus, there are internal `gnome-desktop`, `kde-desktop`, `lxde-desktop` and `xfce-desktop` tasks, none of which are offered in `tasksel`'s menu. Likewise, there are no menu entries for tasks for languages, but the user's language choice during the install influences the selection of corresponding language tasks.

440

When developing a desktop live image, the image typically boots directly to a working desktop, the choices of both desktop and default language having been made at build time, not at run time as in the case of the Debian Installer. That's not to say that a live image couldn't be built to support multiple desktops or multiple languages and offer the user a choice, but that is not live-build's default behaviour.

441

Because there is no provision made automatically for language tasks, which include such things as language-specific fonts and input-method packages, if you want them, you need to specify them in your configuration. For example, a GNOME desktop image containing support for German might include these task metapackages:

442

$ lb config
$ echo "task-gnome-desktop task-laptop" >> config/package-lists/my.list.chroot
$ echo "task-german task-german-desktop task-german-gnome-desktop" >> config/package-lists/my.list.chroot

443

###### 8.2.10 Kernel flavour and version

444

One or more kernel flavours will be included in your image by default, depending on the architecture. You can choose different flavours via the `--linux-flavours` option. Each flavour is suffixed to the default stub `linux-image` to form each metapackage name which in turn depends on an exact kernel package to be included in your image.

445

Thus by default, an `amd64` architecture image will include the `linux-image-amd64` flavour metapackage, and an `i386` architecture image will include the `linux-image-586` metapackage.

446

When more than one kernel package version is available in your configured archives, you can specify a different kernel package name stub with the `--linux-packages` option. For example, supposing you are building an `amd64` architecture image and add the experimental archive for testing purposes so you can install the `linux-image-3.18.0-trunk-amd64` kernel. You would configure that image as follows:

447

$ lb config --linux-packages linux-image-3.18.0-trunk
$ echo "deb http://deb.debian.org/debian/ experimental main" > config/archives/experimental.list.chroot

448

###### 8.2.11 Custom kernels

449

You can build and include your own custom kernels, so long as they are integrated within the Debian package management system. The live-build system does not support kernels not built as `.deb` packages.

450

The proper and recommended way to deploy your own kernel packages is to follow the instructions in the `kernel-handbook`. Remember to modify the ABI and flavour suffixes appropriately, then include a complete build of the `linux` and matching `linux-latest` packages in your repository.

451

If you opt to build the kernel packages without the matching metapackages, you need to specify an appropriate `--linux-packages` stub as discussed in Kernel flavour and version. As we explain in Installing modified or third-party packages, it is best if you include your custom kernel packages in your own repository, though the alternatives discussed in that section work as well.

452

It is beyond the scope of this document to give advice on how to customize your kernel. However, you must at least ensure your configuration satisfies these minimum requirements:

453

- Use an initial ramdisk.

454

- Include the union filesystem module (i.e. usually `OverlayFS`).

455

- Include any other filesystem modules required by your configuration (i.e. usually `squashfs`).

456

##### 8.3 Installing modified or third-party packages

457

While it is against the philosophy of a live system, it may sometimes be necessary to build a live system with modified versions of packages that are in the Debian repository. This may be to modify or support additional features, languages and branding, or even to remove elements of existing packages that are undesirable. Similarly, "third-party" packages may be used to add bespoke and/or proprietary functionality.

458

This section does not cover advice regarding building or maintaining modified packages. Joachim Breitner's 'How to fork privately' method from ‹http://www.joachim-breitner.de/blog/archives/282-How-to-fork-privately.html› may be of interest, however. The creation of bespoke packages is covered in the Debian New Maintainers' Guide at ‹https://www.debian.org/doc/manuals/maint-guide/› and elsewhere.

459

There are two ways of installing modified custom packages:

460

- `packages.chroot`

461

- Using a custom APT repository

462

Using `packages.chroot` is simpler to achieve and useful for "one-off" customizations but has a number of drawbacks, while using a custom APT repository is more time-consuming to set up.

463

###### 8.3.1 Using `packages.chroot` to install custom packages

464

To install a custom package, simply copy it to the `config/packages.chroot/` directory. Packages that are inside this directory will be automatically installed into the live system during build - you do not need to specify them elsewhere.

465

Packages must be named in the prescribed way. One simple way to do this is to use `dpkg-name`.

466

Using `packages.chroot` for installation of custom packages has disadvantages:

467

- It is not possible to use secure APT.

468

- You must install all appropriate packages in the `config/packages.chroot/` directory.

469

- It does not lend itself to storing live system configurations in revision control.

470

###### 8.3.2 Using an APT repository to install custom packages

471

Unlike using `packages.chroot`, when using a custom APT repository you must ensure that you specify the packages elsewhere. See Choosing packages to install for details.

472

While it may seem unnecessary effort to create an APT repository to install custom packages, the infrastructure can be easily re-used at a later date to offer updates of the modified packages.

473

The APT repository does not necessarily need to be online, you can use a local repository instead. However, in both cases the repository needs to be signed.

474

Example:

475

$ gpg --armor --output config/archives/custom_repo.gpg.key${EXTENSION} --export-options export-minimal --export ${SIGNING_KEY}
$ cat << EOF > config/archives/custom_repo.list${EXTENSION}
deb [signed-by=/etc/apt/trusted.gpg.d/custom_repo.gpg.key${EXTENSION}.asc] ${URI} ${SUITE} ${COMPONENTS}
EOF
$ echo "${PACKAGES_FROM_REPOSITORY}" > config/package-lists/custom_repo.list${EXTENSION}

476

Where:

477

- `${EXTENSION}` : the optional stage suffix, see the summary

478

- `${SIGNING_KEY}`: the keyID of the signature of the repository

479

- `${URI}`: the URI to the repository, e.g. `http://deb.debian.org/debian/` or `file://$(pwd)/my_local_repository`

480

- `${SUITE}`: the suite within the repository, e.g. `my-debian-based-distro`

481

- `${COMPONENTS}`: the components within the repository, e.g. `main`

482

- `${PACKAGES_FROM_REPOSITORY}`: the names of the packages to install (dependencies will automatically be installed as well)

483

###### 8.3.3 Custom packages and APT

484

live-build uses APT to install all packages into the live system so will therefore inherit behaviours from this program. One relevant example is that (assuming a default configuration) given a package available in two different repositories with different version numbers, APT will elect to install the package with the higher version number.

485

Because of this, you may wish to increment the version number in your custom packages' `debian/changelog` files to ensure that your modified version is installed over one in the official Debian repositories. This may also be achieved by altering the live system's APT pinning preferences - see APT pinning for more information.

486

##### 8.4 Configuring APT at build time

487

You can configure APT through a number of options applied only at build time. (APT configuration used in the running live system may be configured in the normal way for live system contents, that is, by including the appropriate configurations through `config/includes.chroot/`.) For a complete list, look for options starting with `apt` in the `lb_config` man page.

488

###### 8.4.1 Choosing apt or aptitude

489

You can elect to use either apt or aptitude when installing packages at build time. Which utility is used is governed by the `--apt` argument to `lb config`. Choose the method implementing the preferred behaviour for package installation, the notable difference being how missing packages are handled.

490

- `apt`: With this method, if a missing package is specified, the package installation will fail. This is the default setting.

491

- `aptitude`: With this method, if a missing package is specified, the package installation will succeed.

492

###### 8.4.2 Using a proxy with APT

493

One commonly required APT configuration is to deal with building an image behind a proxy. You may specify your APT proxy with the `--apt-http-proxy` option as needed, e.g.

494

$ lb config --apt-http-proxy http://proxy/

495

###### 8.4.3 Tweaking APT to save space

496

You may find yourself needing to save some space on the image medium, in which case one or the other or both of the following options may be of interest.

497

If you don't want to include APT indices in the image, you can omit those with:

498

$ lb config --apt-indices false

499

This will not influence the entries in `/etc/apt/sources.list`, but merely whether `/var/lib/apt` contains the indices files or not. The tradeoff is that APT needs those indices in order to operate in the live system, so before performing `apt-cache search` or `apt-get install`, for instance, the user must `apt-get update` first to create those indices.

500

If you find the installation of recommended packages bloats your image too much, provided you are prepared to deal with the consequences discussed below, you may disable that default option of APT with:

501

$ lb config --apt-recommends false

502

The most important consequence of turning off recommends is that `live-boot` and `live-config` themselves recommend some packages that provide important functionality used by most Live configurations.

503

Two packages which you most probably will want to add again are:

504

- `user-setup` which `live-config` recommends is used to create the live user.

505

- `sudo` which `live-config` recommends is used to obtain root access in the live-image, which is needed to shutdown the computer.

506

$ lb config --apt-recommends false
$ echo "user-setup sudo" > config/package-lists/recommends.list.chroot

507

In all but the most exceptional circumstances you need to add back at least some of these recommends to your package lists or else your image will not work as expected, if at all. Look at the recommended packages for each of the `live-*` packages included in your build and if you are not certain you can omit them, add them back into your package lists.

508

The more general consequence is that if you don't install recommended packages for any given package, that is, "packages that would be found together with this one in all but unusual installations" ( Debian Policy Manual, section 7.2 ), some packages that users of your Live system actually need may be omitted. Therefore, we suggest you review the difference turning off recommends makes to your packages list (see the `binary.packages` file generated by `lb build`) and re-include in your list any missing packages that you still want installed. Alternatively, if you find you only want a small number of recommended packages left out, leave recommends enabled and set a negative APT pin priority on selected packages to prevent them from being installed, as explained in APT pinning.

509

###### 8.4.4 Passing options to apt or aptitude

510

If there is not a `lb config` option to alter APT's behaviour in the way you need, use `--apt-options` or `--aptitude-options` to pass any options through to your configured APT tool. See the man pages for `apt` and `aptitude` for details. Note that both options have default values that you will need to retain in addition to any overrides you may provide. So, for example, suppose you have included something from `snapshot.debian.org` for testing purposes and want to specify `Acquire::Check-Valid-Until=false` to make APT happy with the stale `Release` file, you would do so as per the following example, appending the new option after the default value `--yes`:

511

$ lb config --apt-options "--yes -oAcquire::Check-Valid-Until=false"

512

Please check the man pages to fully understand these options and when to use them. This is an example only and should not be construed as advice to configure your image this way. This option would not be appropriate for, say, a final release of a live image.

513

For more complicated APT configurations involving `apt.conf` options you might want to create a `config/apt/apt.conf` file instead. See also the other `apt-*` options for a few convenient shortcuts for frequently needed options.

514

###### 8.4.5 APT pinning

515

For background, please first read the `apt_preferences(5)` man page. APT pinning can be configured either for build time, or else for run time. For the former, create `config/archives/*.pref`, `config/archives/*.pref.chroot`, and `config/apt/preferences`. For the latter, create `config/includes.chroot/etc/apt/preferences`.

516

Let's say you are building a trixie live system but need all the live packages that end up in the binary image to be installed from sid at build time. You need to add sid to your APT sources and pin the live packages from it higher, but all other packages from it lower, than the default priority. Thus, only the packages you want are installed from sid at build time and all others are taken from the target system distribution, trixie. The following will accomplish this:

517

$ echo "deb http://mirror/debian/ sid main" > config/archives/sid.list.chroot
$ cat >> config/archives/sid.pref.chroot << EOF
Package: live-*
Pin: release n=sid
Pin-Priority: 600
Package: *
Pin: release n=sid
Pin-Priority: 1
EOF

518

Negative pin priorities will prevent a package from being installed, as in the case where you do not want a package that is recommended by another package. Suppose you are building an LXDE image using `task-lxde-desktop` in `config/package-lists/desktop.list.chroot`, but don't want the user prompted to store wifi passwords in the keyring. This metapackage depends on lxde-core, which recommends gksu, which in turn recommends gnome-keyring. So you want to omit the recommended gnome-keyring package. This can be done by adding the following stanza to `config/apt/preferences`:

519

Package: gnome-keyring
Pin: version *
Pin-Priority: -1

520

# Customizing contents

521

#### 9. Customizing contents

522

This chapter discusses fine-tuning customization of the live system contents beyond merely choosing which packages to include. Includes allow you to add or replace arbitrary files in your live system image, hooks allow you to execute arbitrary commands at different stages of the build and at boot time, and preseeding allows you to configure packages when they are installed by supplying answers to debconf questions.

523

##### 9.1 Includes

524

While ideally a live system would include files entirely provided by unmodified packages, it is sometimes convenient to provide or modify some content by means of files. Using includes, it is possible to add (or replace) arbitrary files in your live system image. live-build provides two mechanisms for using them:

525

- Chroot local includes: These allow you to add or replace files to the chroot/Live filesystem. Please see Live/chroot local includes for more information.

526

- Binary local includes: These allow you to add or replace files in the binary image. Please see Binary local includes for more information.

527

Please see Terms for more information about the distinction between the "Live" and "binary" images.

528

###### 9.1.1 Live/chroot local includes

529

Chroot local includes can be used to add or replace files in the chroot/Live filesystem so that they may be used in the Live system. A typical use is to populate the skeleton user directory (`/etc/skel`) used by the Live system to create the live user's home directory. Another is to supply configuration files that can be simply added or replaced in the image without processing; see Chroot local hooks if processing is needed.

530

To include files, simply add them to your `config/includes.chroot` directory. This directory corresponds to the root directory `/` of the live system. For example, to add a file `/var/www/index.html` in the live system, use:

531

$ mkdir -p config/includes.chroot/var/www
$ cp /path/to/my/index.html config/includes.chroot/var/www

532

Your configuration will then have the following layout:

533

-- config
[...]
|-- includes.chroot
| `-- var
| `-- www
| `-- index.html
[...]

534

Chroot local includes are installed after package installation so that files installed by packages are overwritten.

535

###### 9.1.2 Binary local includes

536

To include material such as documentation or videos on the medium filesystem so that it is accessible immediately upon insertion of the medium without booting the Live system, you can use binary local includes. This works in a similar fashion to chroot local includes. For example, suppose the files `~/video_demo.*` are demo videos of the live system described by and linked to by an HTML index page. Simply copy the material to `config/includes.binary/` as follows:

537

$ cp ~/video_demo.* config/includes.binary/

538

These files will now appear in the root directory of the live medium.

539

##### 9.2 Hooks

540

Hooks allow commands to be run in the chroot and binary stages of the build in order to customize the image. Depending on whether you are building a live image or a regular system image you have to place your hooks in `config/hooks/live` or `config/hooks/normal` respectively. These are frequently referred to as local hooks because they are executed inside the build environment.

541

There are also boot-time hooks that allow you to run commands once the image has already been built, during the boot process.

542

###### 9.2.1 Chroot local hooks

543

To run commands in the chroot stage, create a hook script with a `.hook.chroot` suffix containing the commands either in the `config/hooks/live` or `config/hooks/normal` directories. The hook will run in the chroot after the rest of your chroot configuration has been applied, so remember to ensure your configuration includes all packages and files your hook needs in order to run. See the example chroot hook scripts for various common chroot customization tasks provided in `/usr/share/doc/live-build/examples/hooks` which you can copy or symlink to use them in your own configuration.

544

###### 9.2.2 Binary local hooks

545

To run commands in the binary stage, create a hook script with a `.hook.binary` suffix containing the commands either in the `config/hooks/live` or `config/hooks/normal` directories. The hook will run after all other binary commands are run, but before binary_checksums, the very last binary command. The commands in your hook do not run in the chroot, so take care not to modify any files outside of the build tree, or you may damage your build system! See the example binary hook scripts for various common binary customization tasks provided in `/usr/share/doc/live-build/examples/hooks` which you can copy or symlink to use them in your own configuration.

546

###### 9.2.3 Boot-time hooks

547

To execute commands at boot time, you can supply live-config hooks as explained in the "Customization" section of its man page. Examine live-config's own hooks provided in `/lib/live/config/`, noting the sequence numbers. Then provide your own hook prefixed with an appropriate sequence number, either as a chroot local include in `config/includes.chroot/lib/live/config/`, or as a custom package as discussed in Installing modified or third-party packages.

548

##### 9.3 Preseeding Debconf questions

549

Files in the `config/preseed/` directory suffixed with `.cfg` followed by the stage (`.chroot` or `.binary`) are considered to be debconf preseed files and are installed by live-build using `debconf-set-selections` during the corresponding stage.

550

For more information about debconf, please see `debconf(7)` in the debconf package.

551

# Customizing run time behaviours

552

#### 10. Customizing run time behaviours

553

All configuration that is done during run time is done by live-config. Here are some of the most common options of live-config that users are interested in. A full list of all possibilities can be found in the man page of live-config.

554

##### 10.1 Customizing the live user

555

One important consideration is that the live user is created by live-boot at boot time, not by live-build at build time. This not only influences where materials relating to the live user are introduced in your build, as discussed in Live/chroot local includes, but also any groups and permissions associated with the live user.

556

You can specify additional groups that the live user will belong to by using any of the possibilities to configure live-config. For example, to add the live user to the `fuse` group, you can either add the following file in `config/includes.chroot/etc/live/config.conf.d/10-user-setup.conf`:

557

LIVE_USER_DEFAULT_GROUPS="audio cdrom dip floppy video plugdev netdev powerdev scanner bluetooth fuse"

558

or use `live-config.user-default-groups=audio,cdrom,dip,floppy,video,plugdev,netdev,powerdev,scanner,bluetooth,fuse` as a boot parameter.

559

It is also possible to change the default username "user" and the default password "live". If you want to do that for any reason, you can easily achieve it as follows:

560

To change the default username you can simply specify it in your config:

561

$ lb config --bootappend-live "boot=live components username=live-user"

562

One possible way of changing the default password is by means of a hook as described in Boot-time hooks. In order to do that you can use the "passwd" hook from `/usr/share/doc/live-config/examples/hooks`, prefix it accordingly (e.g. 2000-passwd) and add it to `config/includes.chroot/lib/live/config/`

563

##### 10.2 Customizing locale and language

564

When the live system boots, language is involved in two steps:

565

- the locale generation

566

- setting the keyboard configuration

567

The default locale when building a Live system is `locales=en_US.UTF-8`. To define the locale that should be generated, use the `locales` parameter in the `--bootappend-live` option of `lb config`, e.g.

568

$ lb config --bootappend-live "boot=live components locales=de_CH.UTF-8"

569

Multiple locales may be specified as a comma-delimited list.

570

This parameter, as well as the keyboard configuration parameters indicated below, can also be used at the kernel command line. You can specify a locale by `language_country` (in which case the default encoding is used) or the full `language_country.encoding` word. A list of supported locales and the encoding for each can be found in `/usr/share/i18n/SUPPORTED`.

571

Both the console and X keyboard configuration are performed by `live-config` using the `console-setup` package. To configure them, use the `keyboard-layouts`, `keyboard-variants`, `keyboard-options` and `keyboard-model` boot parameters via the `--bootappend-live` option. Valid options for these can be found in `/usr/share/X11/xkb/rules/base.lst`. To find layouts and variants for a given language, try searching for the English name of the language and/or the country where the language is spoken, e.g:

572

$ egrep -i '(^!|german.*switzerland)' /usr/share/X11/xkb/rules/base.lst
! model
! layout
ch German (Switzerland)
! variant
legacy ch: German (Switzerland, legacy)
de_nodeadkeys ch: German (Switzerland, eliminate dead keys)
de_sundeadkeys ch: German (Switzerland, Sun dead keys)
de_mac ch: German (Switzerland, Macintosh)
! option

573

Note that each variant lists the layout to which it applies in the description.

574

Often, only the layout needs to be configured. For example, to get the locale files for German and Swiss German keyboard layout in X use:

575

$ lb config --bootappend-live "boot=live components locales=de_CH.UTF-8 keyboard-layouts=ch"

576

However, for very specific use cases, you may wish to include other parameters. For example, to set up a French system with a French-Dvorak layout (called Bepo) on a TypeMatrix EZ-Reach 2030 USB keyboard, use:

577

$ lb config --bootappend-live \
"boot=live components locales=fr_FR.UTF-8 keyboard-layouts=fr keyboard-variants=bepo keyboard-model=tm2030usb"

578

Multiple values may be specified as comma-delimited lists for each of the `keyboard-*` options, with the exception of `keyboard-model`, which accepts only one value. Please see the `keyboard(5)` man page for details and examples of `XKBMODEL`, `XKBLAYOUT`, `XKBVARIANT` and `XKBOPTIONS` variables. If multiple `keyboard-variants` values are given, they will be matched one-to-one with `keyboard-layouts` values (see `setxkbmap(1)` `-variant` option). Empty values are allowed; e.g. to define two layouts, the default being US QWERTY and the other being US Dvorak, use:

579

$ lb config --bootappend-live \
"boot=live components keyboard-layouts=us,us keyboard-variants=,dvorak"

580

##### 10.3 Persistence

581

A live cd paradigm is a pre-installed system which runs from read-only media, like a cdrom, where writes and modifications do not survive reboots of the host hardware which runs it.

582

A live system is a generalization of this paradigm and thus supports other media in addition to CDs; but still, in its default behaviour, it should be considered read-only and all the run-time evolutions of the system are lost at shutdown.

583

'Persistence' is a common name for different kinds of solutions for saving across reboots some, or all, of this run-time evolution of the system. To understand how it works it would be handy to know that even if the system is booted and run from read-only media, modifications to the files and directories are written on writable media, typically a ram disk (tmpfs) and ram disks' data do not survive reboots.

584

The data stored on this ramdisk should be saved on a writable persistent medium like local storage media, a network share or even a session of a multisession (re)writable CD/DVD. All these media are supported in live systems in different ways, and all but the last one require a special boot parameter to be specified at boot time: `persistence`.

585

If the boot parameter `persistence` is set (and `nopersistence` is not set), local storage media (e.g. hard disks, USB drives) will be probed for persistence volumes during boot. It is possible to restrict which types of persistence volumes to use by specifying certain boot parameters described in the live-boot(7) man page. A persistence volume is any of the following:

586

- a partition, identified by its GPT name.

587

- a filesystem, identified by its filesystem label.

588

- an image file located on the root of any readable filesystem (even an NTFS partition of a foreign OS), identified by its filename.

589

The volume label for overlays must be `persistence` but it will be ignored unless it contains in its root a file named `persistence.conf` which is used to fully customize the volume's persistence, this is to say, specifying the directories that you want to save in your persistence volume after a reboot. See The persistence.conf file for more details.

590

Here are some examples of how to prepare a volume to be used for persistence. It can be, for instance, an ext4 partition on a hard disk or on a usb key created with, e.g.:

591

# mkfs.ext4 -L persistence /dev/sdb1

592

See also Using the space left on a USB stick.

593

If you already have a partition on your device, you could just change the label with one of the following:

594

# tune2fs -L persistence /dev/sdb1 # for ext2,3,4 filesystems

595

Here's an example of how to create an ext4-based image file to be used for persistence:

596

$ dd if=/dev/null of=persistence bs=1 count=0 seek=1G # for a 1GB sized image file
$ /sbin/mkfs.ext4 -F persistence

597

Once the image file is created, as an example, to make `/usr` persistent but only saving the changes you make to that directory and not all the contents of `/usr`, you can use the "union" option. If the image file is located in your home directory, copy it to the root of your hard drive's filesystem and mount it in `/mnt` as follows:

598

# cp persistence /
# mount -t ext4 /persistence /mnt

599

Then, create the `persistence.conf` file adding content and unmount the image file.

600

# echo "/usr union" >> /mnt/persistence.conf
# umount /mnt

601

Now, reboot into your live medium with the boot parameter "persistence".

602

###### 10.3.1 The persistence.conf file

603

A volume with the label `persistence` must be configured by means of the `persistence.conf` file to make arbitrary directories persistent. That file, located on the volume's filesystem root, controls which directories it makes persistent, and in which way.

604

How custom overlay mounts are configured is described in full detail in the persistence.conf(5) man page, but a simple example should be sufficient for most uses. Let's say we want to make our home directory and APT cache persistent in an ext4 filesystem on the /dev/sdb1 partition:

605

# mkfs.ext4 -L persistence /dev/sdb1
# mount -t ext4 /dev/sdb1 /mnt
# echo "/home" >> /mnt/persistence.conf
# echo "/var/cache/apt" >> /mnt/persistence.conf
# umount /mnt

606

Then we reboot. During the first boot the contents of `/home` and `/var/cache/apt` will be copied into the persistence volume, and from then on all changes to these directories will live in the persistence volume. Please note that any paths listed in the `persistence.conf` file cannot contain white spaces or the special `.` and `..` path components. Also, neither `/lib`, `/lib/live` (or any of their sub-directories) nor `/` can be made persistent using custom mounts. As a workaround for this limitation you can add `/ union` to your `persistence.conf` file to achieve full persistence.

607

###### 10.3.2 Using more than one persistence store

608

There are different methods of using multiple persistence store for different use cases. For instance, using several volumes at the same time or selecting only one, among various, for very specific purposes.

609

Several different custom overlay volumes (with their own `persistence.conf` files) can be used at the same time, but if several volumes make the same directory persistent, only one of them will be used. If any two mounts are "nested" (i.e. one is a sub-directory of the other) the parent will be mounted before the child so no mount will be hidden by the other. Nested custom mounts are problematic if they are listed in the same `persistence.conf` file. See the persistence.conf(5) man page for how to handle that case if you really need it (hint: you usually don't).

610

One possible use case: If you wish to store the user data i.e. `/home` and the superuser data i.e. `/root` in different partitions, create two partitions with the `persistence` label and add a `persistence.conf` file in each one like this, `# echo "/home" > persistence.conf` for the first partition that will save the user's files and `# echo "/root" > persistence.conf` for the second partition which will store the superuser's files. Finally, use the `persistence` boot parameter.

611

If a user would need multiple persistence store of the same type for different locations or testing, such as `private` and `work`, the boot parameter `persistence-label` used in conjunction with the boot parameter `persistence` will allow for multiple but unique persistence media. An example would be if a user wanted to use a persistence partition labeled `private` for personal data like browser bookmarks or other types, they would use the boot parameters: `persistence` `persistence-label=private`. And to store work related data, like documents, research projects or other types, they would use the boot parameters: `persistence` `persistence-label=work`.

612

It is important to remember that each of these volumes, `private` and `work`, also needs a `persistence.conf` file in its root. The live-boot man page contains more information about how to use these labels with legacy names.

613

###### 10.3.3 Using persistence with encryption

614

Using the persistence feature means that some sensible data might get exposed to risk. Especially if the persistent data is stored on a portable device such as a usb stick or an external hard drive. That is when encryption comes in handy. Even if the entire procedure might seem complicated because of the number of steps to be taken, it is really easy to handle encrypted partitions with live-boot. In order to use luks, which is the supported encryption type, you need to install cryptsetup both on the machine you are creating the encrypted partition with and also in the live system you are going to use the encrypted persistent partition with.

615

To install cryptsetup on your machine:

616

# apt-get install cryptsetup

617

To install cryptsetup in your live system, add it to your package-lists:

618

$ lb config
$ echo "cryptsetup cryptsetup-initramfs" > config/package-lists/encryption.list.chroot

619

Once you have your live system with cryptsetup, you basically only need to create a new partition, encrypt it and boot with the `persistence` and `persistence-encryption=luks` parameters. We could have already anticipated this step and added the boot parameters following the usual procedure:

620

$ lb config --bootappend-live "boot=live components persistence persistence-encryption=luks"

621

Let's go into the details for all of those who are not familiar with encryption. In the following example we are going to use a partition on a usb stick which corresponds to `/dev/sdc2`. Please be warned that you need to determine which partition is the one you are going to use in your specific case.

622

The first step is plugging in your usb stick and determine which device it is. The recommended method of listing devices in live-manual is using `ls -l /dev/disk/by-id`. After that, create a new partition and then, encrypt it with a passphrase as follows:

623

# cryptsetup --verify-passphrase luksFormat /dev/sdc2

624

Then open the luks partition in the virtual device mapper. Use any name you like. We use live here as an example:

625

# cryptsetup luksOpen /dev/sdc2 live

626

The next step is filling the device with zeros before creating the filesystem:

627

# dd if=/dev/zero of=/dev/mapper/live

628

Now, we are ready to create the filesystem. Notice that we are adding the label `persistence` so that the device is mounted as persistence store at boot time.

629

# mkfs.ext4 -L persistence /dev/mapper/live

630

To continue with our setup, we need to mount the device, for example in `/mnt`.

631

# mount /dev/mapper/live /mnt

632

And create the `persistence.conf` file in the root of the partition. This is, as explained before, strictly necessary. See The persistence.conf file.

633

# echo "/ union" > /mnt/persistence.conf

634

Then unmount the mount point:

635

# umount /mnt

636

And optionally, although it might be a good way of securing the data we have just added to the partition, we can close the device:

637

# cryptsetup luksClose live

638

Let's summarize the process. So far, we have created an encryption capable live system, which can be copied to a usb stick as explained in Copying an ISO hybrid image to a USB stick. We have also created an encrypted partition, which can be located in the same usb stick to carry it around and we have configured the encrypted partition to be used as persistence store. So now, we only need to boot the live system. At boot time, live-boot will prompt us for the passphrase and will mount the encrypted partition to be used for persistence.

639

# Customizing the binary image

640

#### 11. Customizing the binary image

641

##### 11.1 Bootloaders

642

live-build uses syslinux and some of its derivatives (depending on the image type) as bootloaders by default. They can be easily customized to suit your needs.

643

In order to use a full theme, copy `/usr/share/live/build/bootloaders` into `config/bootloaders` and edit the files in there. If you do not want to bother modifying all supported bootloader configurations, only providing a local customized copy of one of the bootloaders, e.g. isolinux in `config/bootloaders/isolinux` is enough too, depending on your use case.

644

When modifying one of the default themes, if you want to use a personalized background image that will be displayed together with the boot menu, add a splash.png picture of 640x480 pixels. Then, remove the splash.svg file.

645

There are many possibilities when it comes to making changes. For instance, syslinux derivatives are configured by default with a timeout of 0 (zero) which means that they will pause indefinitely at their splash screen until you press a key.

646

To modify the boot timeout of a default `iso-hybrid` image just edit a default isolinux.cfg file specifying the timeout in units of 1/10 seconds. A modified isolinux.cfg to boot after five seconds would be similar to this:

647

include menu.cfg
default vesamenu.c32
prompt 0
timeout 50

648

##### 11.2 ISO metadata

649

When creating an ISO9660 binary image, you can use the following options to add various textual metadata for your image. This can help you easily identify the version or configuration of an image without booting it.

650

- `LB_ISO_APPLICATION/--iso-application NAME`: This should describe the application that will be on the image. The maximum length for this field is 128 characters.

651

- `LB_ISO_PREPARER/--iso-preparer NAME`: This should describe the preparer of the image, usually with some contact details. The default for this option is the live-build version you are using, which may help with debugging later. The maximum length for this field is 128 characters.

652

- `LB_ISO_PUBLISHER/--iso-publisher NAME`: This should describe the publisher of the image, usually with some contact details. The maximum length for this field is 128 characters.

653

- `LB_ISO_VOLUME/--iso-volume NAME`: This should specify the volume ID of the image. This is used as a user-visible label on some platforms such as Windows and Apple Mac OS. The maximum length for this field is 32 characters.

654

# Customizing Debian Installer

655

#### 12. Customizing Debian Installer

656

Live system images can be integrated with Debian Installer. There are a number of different types of installation, varying in what is included and how the installer operates.

657

Please note the careful use of capital letters when referring to the "Debian Installer" in this section - when used like this we refer explicitly to the official installer for the Debian system, not anything else. It is often seen abbreviated to "d-i".

658

##### 12.1 Types of Debian Installer

659

The three main types of installer are:

660

"Normal" Debian Installer: This is a normal live system image with a separate kernel and initrd which (when selected from the appropriate bootloader) launches into a standard Debian Installer instance, just as if you had downloaded a CD image of Debian and booted it. Images containing a live system and such an otherwise independent installer are often referred to as "combined images".

661

On such images, Debian is installed by fetching and installing .deb packages using debootstrap, from local media or some network-based network, resulting in a default Debian system being installed to the hard disk.

662

This whole process can be preseeded and customized in a number of ways; see the relevant pages in the Debian Installer manual for more information. Once you have a working preseeding file, live-build can automatically put it in the image and enable it for you.

663

"Live" Debian Installer: This is a live system image with a separate kernel and initrd which (when selected from the appropriate bootloader) launches into an instance of the Debian Installer.

664

Installation will proceed in an identical fashion to the "normal" installation described above, but at the actual package installation stage, instead of using debootstrap to fetch and install packages, the live filesystem image is copied to the target. This is achieved with a special udeb called live-installer.

665

After this stage, the Debian Installer continues as normal, installing and configuring items such as bootloaders and local users, etc.

666

Note: to support both normal and live installer entries in the bootloader of the same live medium, you must disable live-installer by preseeding `live-installer/enable=false`.

667

"Desktop" Debian Installer: Regardless of the type of Debian Installer included, `d-i` can be launched from the Desktop by clicking on an icon. This is user friendlier in some situations. In order to make use of this, the debian-installer-launcher package needs to be included.

668

Note that by default, live-build does not include Debian Installer images in the images, it needs to be specifically enabled with `lb config`. Also, please note that for the "Desktop" installer to work, the kernel of the live system must match the kernel `d-i` uses for the specified architecture. For example:

669

$ lb config --debian-installer live
$ echo debian-installer-launcher >> config/package-lists/my.list.chroot

670

##### 12.2 Customizing Debian Installer by preseeding

671

As described in the Debian Installer Manual, Appendix B at ‹https://www.debian.org/releases/stable/amd64/apb.en.html›, "Preseeding provides a way to set answers to questions asked during the installation process, without having to manually enter the answers while the installation is running. This makes it possible to fully automate most types of installation and even offers some features not available during normal installations." This kind of customization is best accomplished with live-build by placing the configuration in a `preseed.cfg` file included in `config/includes.installer/`. For example, to preseed setting the locale to `en_US`:

672

$ echo "d-i debian-installer/locale string en_US" \
>> config/includes.installer/preseed.cfg

673

##### 12.3 Customizing Debian Installer content

674

For experimental or debugging purposes, you might want to include locally built `d-i` component udeb packages. Place these in `config/packages.binary/` to include them in the image. Additional or replacement files and directories may be included in the installer initrd as well, in a similar fashion to Live/chroot local includes, by placing the material in `config/includes.installer/`.

675

# Projekt

676

# Contributing to the project

677

#### 13. Contributing to the project

678

When submitting a contribution, please clearly identify its copyright holder and include any applicable licensing statement. Note that to be accepted, the contribution must be licensed under the same license as the rest of the documents, namely, GPL version 3 or later.

679

Contributions to the project, such as translations and patches, are greatly welcome. Anyone can send merge requests. The projects are hosted on Salsa: ‹https://salsa.debian.org/live-team› follow Salsa's documentation for instructions on how to contribute.

680

Even though all commits might be revised, we ask you to use your common sense and make good commits with good commit messages.

681

- Write commit messages that consist of complete, meaningful sentences in English, starting with a capital letter and ending with a full stop. Usually, these will start with the form "Fixing/Adding/Removing/Correcting/Translating/...".

682

- Write good commit messages. The first line must be an accurate summary of the contents of the commit which will be included in the changelog. If you need to make some further explanations, write them below leaving a blank line after the first one and then another blank line after each paragraph. Lines of paragraphs should not exceed 80 characters in length.

683

- Commit atomically, this is to say, do not mix unrelated things in the same commit. Make one different commit for each change you make.

684

##### 13.1 Translation of man pages

685

You can also contribute to the project working on the translation of the man pages for the different live-* packages that the project maintains. The procedure is different depending on whether you are starting a translation from scratch or continue working on an already existing one:

686

- Working on an already existing translation

687

If you want to maintain the translation of an already existing language you have to make your changes to your `manpages/po/${LANGUAGE}/*.po` file or files and then run `make rebuild` from inside the `manpages/` directory. This will update the actual man pages in `manpages/${LANGUAGE}/*`

688

- Starting a new translation from scratch

689

In order to add a new translation of any of the project's man pages you have to follow a similar procedure. It could be summarized as follows:

690

- Open the `manpages/pot/` file or files in your favourite editor, such as poedit, and save it as a .po file in `manpages/po/${LANGUAGE}/`. (You will have to create your `${LANGUAGE}/` directory).

691

- Run `make rebuild` from inside the `manpages/` directory to create the `manpages/${LANGUAGE}/` files which will contain the actual man pages.

692

Remember that you will have to add all the directories and files, then make the commit and finally push to the git server.

693

# Reporting bugs

694

#### 14. Reporting bugs

695

Live systems are far from being perfect, but we want to make it as close as possible to perfect - with your help. Do not hesitate to report a bug. It is better to fill a report twice than never. However, this chapter includes recommendations on how to file good bug reports.

696

For the impatient:

697

- First check whether the bugs has been reported already. You can see the full list of bugs that are assigned to the live-team at ‹https://bugs.debian.org/cgi-bin/pkgreport.cgi?maint=debian-live%40lists.debian.org›.

698

- Before submitting a bug report always try to reproduce the bug with the most recent versions of the packages of live-build, live-boot, live-config and live-tools that you're using.

699

- Try to give as specific information as possible about the bug. This includes (at least) the version of live-build, live-boot, live-config, and live-tools used and the distribution of the live system you are building.

700

##### 14.1 Known issues

701

Currently known issues are listed in the BTS at ‹https://bugs.debian.org/cgi-bin/pkgreport.cgi?maint=debian-live%40lists.debian.org›.

702

Note: Since Debian testing and Debian unstable distributions are moving targets, when you specify either of them as the target system distribution, a successful build may not always be possible.

703

If this causes too much difficulty for you, do not build a system based on testing or unstable, but rather, use stable. live-build always defaults to the stable release.

704

It is out of the scope of this manual to train you to correctly identify and fix problems in packages of the development distributions, however, you can always try the following: If a build fails when the target distribution is testing, try unstable. If unstable does work, revert to testing and pin the newer version of the failing package from unstable (see APT pinning for details).

705

##### 14.2 Do the research

706

Before filing the bug, please search the web for the particular error message or symptom you are getting. As it is highly unlikely that you are the only person experiencing a particular problem. There is always a chance that it has been discussed elsewhere and a possible solution, patch, or workaround has been proposed.

707

You should pay particular attention to the live systems mailing list, as well as the homepage, as these are likely to contain the most up-to-date information. If such information exists, always include the references to it in your bug report.

708

In addition, you should check the current bug lists for live-build, live-boot, live-config and live-tools to see whether something similar has already been reported.

709

##### 14.3 Rebuild from scratch

710

To ensure that a particular bug is not caused by an uncleanly built system, please always rebuild the whole live system from scratch to see if the bug is reproducible.

711

##### 14.4 Use up-to-date packages

712

Using outdated packages can cause significant problems when trying to reproduce (and ultimately fix) your problem. Make sure your build system is up-to-date and any packages included in your image are up-to-date as well. If possible, try to reproduce the bug with the newest code from source, see Installation for details.

713

##### 14.5 Collect information

714

Please provide enough information with your report. Include, at least, the exact version of live-build where the bug is encountered and the steps to reproduce it. Please use your common sense and provide any other relevant information if you think that it might help in solving the problem.

715

To make the most out of your bug report, we require at least the following information:

716

- Architecture of the host system

717

- Distribution of the host system

718

- Version of live-build on the host system

719

- Version of debootstrap on the host system

720

- Architecture of the live system

721

- Distribution of the live system

722

- Version of live-boot on the live system

723

- Version of live-config on the live system

724

- Version of live-tools on the live system

725

You can generate a log of the build process by using the `tee` command. We recommend doing this automatically with an `auto/build` script (see Managing a configuration for details).

726

# lb build 2>&1 | tee build.log

727

At boot time, live-boot and live-config store their logfiles in `/var/log/live/`. Check them for error messages.

728

Additionally, to rule out other errors, it is always a good idea to tar up your `config/` directory and upload it somewhere (do not send it as an attachment to the mailing list), so that we can try to reproduce the errors you encountered. If this is difficult (e.g. due to size) you can use the output of `lb config --dump` which produces a summary of your config tree (i.e. lists files in subdirectories of `config/` but does not include them).

729

Remember to send in any logs that were produced with English locale settings, e.g. run your live-build commands with a leading `LC_ALL=C` or `LC_ALL=en_US`.

730

##### 14.6 Isolate the failing case if possible

731

If possible, isolate the failing case to the smallest possible change that breaks. It is not always easy to do this so if you cannot manage it for your report, do not worry. However, if you plan your development cycle well, using small enough change sets per iteration, you may be able to isolate the problem by constructing a simpler 'base' configuration that closely matches your actual configuration plus just the broken change set added to it. If you have a hard time sorting out which of your changes broke, it may be that you are including too much in each change set and should develop in smaller increments.

732

##### 14.7 Use the correct package to report the bug against

733

In general, you should report build time errors against the live-build package, boot time errors against live-boot, and run time errors against live-config. If you are unsure of which package is appropriate or need more help before submitting a bug report, please report it against the debian-live pseudo-package. We will then take care about it and reassign it where appropriate.

734

However, we would appreciate it if you try to narrow it down according to where the bug appears.

735

###### 14.7.1 At build time while bootstrapping

736

live-build first bootstraps a basic Debian system with debootstrap. If a bug appears here, check if the error is related to a specific Debian package (most likely), or if it is related to the bootstrapping tool itself.

737

In both cases, this is not a bug in the live system, but rather in Debian itself and probably we cannot fix it directly. Please report such a bug against the bootstrapping tool or the failing package.

738

###### 14.7.2 At build time while installing packages

739

live-build installs additional packages from the Debian archive and depending on the Debian distribution used and the daily archive state, it can fail. If a bug appears here, check if the error is also reproducible on a normal system.

740

If this is the case, this is not a bug in the live system, but rather in Debian - please report it against the failing package. Running debootstrap separately from the Live system build or running `lb bootstrap --debug` will give you more information.

741

Also, if you are using a local mirror and/or any sort of proxy and you are experiencing a problem, please always reproduce it first by bootstrapping from an official mirror.

742

###### 14.7.3 At boot time

743

If your image does not boot, please report it to the mailing list together with the information requested in Collect information. Do not forget to mention, how/when the image failed exactly, whether using virtualization or real hardware. If you are using a virtualization technology of any kind, please always run it on real hardware before reporting a bug. Providing a screenshot of the failure is also very helpful.

744

###### 14.7.4 At run time

745

If a package was successfully installed, but fails while actually running the Live system, this is probably a bug in live-config.

746

##### 14.8 Where to report bugs

747

The Debian Live Project keeps track of all bugs in the Bug Tracking System (BTS). For information on how to use the system, please see ‹https://bugs.debian.org/›. You can also submit the bugs by using the `reportbug` command from the package with the same name.

748

Please note that bugs found in distributions derived from Debian (such as Ubuntu and others) should not be reported to the Debian BTS unless they can be also reproduced on a Debian system using official Debian packages.

749

# Coding Style

750

#### 15. Coding Style

751

This chapter documents the coding style used in live systems.

752

##### 15.1 Compatibility

753

- Avoid "bashisms", the codebase must be POSIX compliant and thus universally compatible.

754

- Furthermore it must comply with the version of the POSIX specification chosen by the current Debian Policy.

755

- You can check your scripts with 'sh -n' and 'checkbashisms'.

756

- Make sure all shell code runs with 'set -e'.

757

##### 15.2 Indenting

758

- Always use tabs over spaces.

759

- Keep case branch terminators (";;") aligned with the "content" of the branch, rather than the branch "entry".

760

Good:

761

case "${1}" in
foo)
foobar
;;
bar)
foobar
;;
esac

762

##### 15.3 Wrapping

763

- Generally, lines should be 80 chars at maximum.

764

- Placement of keywords like `then` and `do` should be chosen with good judgement with respect to clutter and readability. For small bits of code in particular it should be preferred to have them on the same line as the prior keyword they relate to (`if`; `for`; etc). Only place on the next line where it makes good sense to do so; typically this might only be to comply with maximum line length restrictions. One situation where they should always be placed on the next line is where what they follow is broken up onto multiple lines, and thus it being on a new line creates clear separation between that and the body of code following it. I.e. :

765

Preferred:

766

if foo; then
bar
fi
for FOO in $ITEMS; do
bar
done
if [ "${MY_LOCATION_VARIABLE}" = "something" ] && [ -e "${MY_OUTPUT_FILE}" ]
then
MY_OTHER_VARIABLE="$(some_bin ${FOOBAR} | awk -F_ '{ print $1 }')"
fi
if [ "${MY_FOO}" = "something" ] && [ -e "path/${FILE_1}" ] ||
[ "${MY_BAR}" = "something_else" ] && [ ${ALLOW} = "true" ]
then
foobar
fi

767

Less ideal:

768

if [ "${MY_LOCATION_VARIABLE}" = "something" ] && [ -e "${MY_OUTPUT_FILE}" ]; then
MY_OTHER_VARIABLE="$(some_bin ${FOOBAR} | awk -F_ '{ print $1 }')"
fi

769

Horrible:

770

if [ "${MY_LOCATION_VARIABLE}" = "something" ] && [ -e "${MY_OUTPUT_FILE}" ] || [ "${MY_LOCATION_VARIABLE}" = "something-else" ] && [ -e "${MY_OUTPUT_FILE_2}" ]; then
MY_OTHER_VARIABLE="$(some_bin ${FOOBAR} | awk -F_ '{ print $1 }')"
fi

771

- Prefer placing the opening brace of a function on a new line (for consistency with established style), and keep the braces aligned with the function name:

772

Good:

773

Foo ()
{
bar
}

774

Bad (inconsistent with existing style):

775

Foo () {
bar
}

776

Awful:

777

Foo ()
{
bar
}

778

##### 15.4 Variables

779

- Variables are always in capital letters.

780

- Config variables used in live-build should start with an `LB_` prefix.

781

- Local function variables should be restricted to local scope.

782

- Variables in connection to a boot parameter in live-config start with `LIVE_`.

783

- All other variables in live-config start with `_` prefix.

784

- Use braces around variables; e.g. write `${FOO}` instead of `$FOO`.

785

- Always protect variables with quotes to respect potential whitespaces (except where necessary to achieve correct word splitting): write `"${FOO}"` not `${FOO}`.

786

- For consistency reasons, always use quotes when assigning values to variables:

787

Bad:

788

FOO=bar

789

Good:

790

FOO="bar"

791

- If multiple variables are used, prefer quoting the full expression:

792

Typically bad:

793

if [ -f "${FOO}"/foo/"${BAR}"/bar ]; then
foobar
fi

794

Good:

795

if [ -f "${FOO}/foo/${BAR}/bar" ]; then
foobar
fi

796

##### 15.5 Miscellaneous

797

- Prefer "`|`" (without the surround quotes) as a separator in calls to sed, e.g. "`sed -e 's|foo|bar|'`" (without "").

798

- Don't use the `test` command for comparisons or tests, use "`[`" and "`]`" (without ""); e.g. "`if [ -x /bin/foo ]; ...`" and not "`if test -x /bin/foo; ...`".

799

- Use `case` wherever it makes code more readable than conditional checks (`if foo; ...` and tests without the actual `if` keyword, e.g. `[ -e "${FILE}" ] || exit 0`).

800

- Use "Foo_bar" style names for functions, i.e. a capital first letter, then all lowercase, with sensible use of underscores for better readability.

801

# Beispiele

802

# Beispiele

803

#### 16. Examples

804

This chapter covers example builds for specific use cases with live systems. If you are new to building your own live system images, we recommend you first look at the three tutorials in sequence, as each one teaches new techniques that will help you use and understand the remaining examples.

805

##### 16.1 Using the examples

806

To use these examples you need a system to build them on that meets the requirements listed in Requirements and has live-build installed as described in Installing live-build.

807

Note that, for the sake of brevity, in these examples we do not specify a local mirror to use for the build. You can speed up downloads considerably if you use a local mirror. You may specify the options when you use `lb config`, as described in Distribution mirrors used at build time, or for more convenience, set the default for your build system in `/etc/live/build.conf`. Simply create this file and in it, set the corresponding `LB_MIRROR_*` variables to your preferred mirror. All other mirrors used in the build will be defaulted from these values. For example:

808

LB_MIRROR_BOOTSTRAP="http://mirror/debian/"
LB_MIRROR_CHROOT_SECURITY="http://mirror/debian-security/"
LB_MIRROR_CHROOT_BACKPORTS="http://mirror/debian-backports/"

809

##### 16.2 Tutorial 1: A default image

810

Use case: Create a simple first image, learning the basics of live-build.

811

In this tutorial, we will build a default ISO hybrid live system image containing only base packages (no Xorg) and some live system support packages, as a first exercise in using live-build.

812

You can't get much simpler than this:

813

$ mkdir tutorial1 ; cd tutorial1 ; lb config

814

Examine the contents of the `config/` directory if you wish. You will see stored here a skeletal configuration, ready to customize or, in this case, use immediately to build a default image.

815

Now, as superuser, build the image, saving a log as you build with `tee`.

816

# lb build 2>&1 | tee build.log

817

Assuming all goes well, after a while, the current directory will contain `live-image-amd64.hybrid.iso`. This ISO hybrid image can be booted directly in a virtual machine as described in Testing an ISO image with Qemu and Testing an ISO image with VirtualBox, or else imaged onto optical media or a USB flash device as described in Burning an ISO image to a physical medium and Copying an ISO hybrid image to a USB stick, respectively.

818

##### 16.3 Tutorial 2: A web browser utility

819

Use case: Create a web browser utility image, learning how to apply customizations.

820

In this tutorial, we will create an image suitable for use as a web browser utility, serving as an introduction to customizing live system images.

821

$ mkdir tutorial2
$ cd tutorial2
$ lb config
$ echo "task-lxde-desktop firefox-esr" >> config/package-lists/my.list.chroot

822

Our choice of LXDE for this example reflects our desire to provide a minimal desktop environment, since the focus of the image is the single use we have in mind, the web browser. We could go even further and provide a default configuration for the web browser in `config/includes.chroot/etc/iceweasel/profile/`, or additional support packages for viewing various kinds of web content, but we leave this as an exercise for the reader.

823

Build the image, again as superuser, keeping a log as in Tutorial 1:

824

# lb build 2>&1 | tee build.log

825

Again, verify the image is OK and test, as in Tutorial 1.

826

##### 16.4 Tutorial 3: A personalized image

827

Use case: Create a project to build a personalized image, containing your favourite software to take with you on a USB stick wherever you go, and evolving in successive revisions as your needs and preferences change.

828

Since we will be changing our personalized image over a number of revisions, and we want to track those changes, trying things experimentally and possibly reverting them if things don't work out, we will keep our configuration in the popular `git` version control system. We will also use the best practice of autoconfiguration via `auto` scripts as described in Managing a configuration.

829

###### 16.4.1 First revision

830

$ mkdir -p tutorial3/auto
$ cp /usr/share/doc/live-build/examples/auto/* tutorial3/auto/
$ cd tutorial3

831

Edit `auto/config` to read as follows:

832

#!/bin/sh
lb config noauto \
--distribution stable \
"${@}"

833

Perform `lb config` to generate the config tree, using the `auto/config` script you just created:

834

$ lb config

835

Now populate your local package list:

836

$ echo "task-lxde-desktop spice-vdagent hexchat" >> config/package-lists/my.list.chroot

837

First, `--distribution stable` ensures that ⌠stable} is used instead of the default {testing⌡. Second, we have added spice-vdagent for easier testing the image in qemu. And finally, we have added an initial favourite package: hexchat.

838

Now, build the image:

839

# lb build

840

Note that unlike in the first two tutorials, we no longer have to type `2>&1 | tee build.log` as that is now included in `auto/build`.

841

Once you've tested the image (as in Tutorial 1) and are satisfied it works, it's time to initialize our `git` repository, adding only the auto scripts we just created, and then make the first commit:

842

$ git init
$ cp /usr/share/doc/live-build/examples/gitignore .gitignore
$ git add .gitignore auto config
$ git commit -m "Initial import."

843

###### 16.4.2 Second revision

844

In this revision, we're going to clean up from the first build, replace the smplayer package with vlc package, rebuild, test and commit.

845

The `lb clean` command will clean up all generated files from the previous build except for the cache, which saves having to re-download packages. This ensures that the subsequent `lb build` will re-run all stages to regenerate the files from our new configuration.

846

# lb clean

847

Now install the vlc package before the lxde package chooses between smplayer, vlc and mplayer-gui in our local package list in `config/package-lists/my.list.chroot`:

848

$ echo "vlc task-lxde-desktop spice-vdagent hexchat" >> config/package-lists/my.list.chroot

849

Build again:

850

# lb build

851

Test, and when you're satisfied, commit the next revision:

852

$ git commit -a -m "Replacing smplayer with vlc."

853

Of course, more complicated changes to the configuration are possible, perhaps adding files in subdirectories of `config/`. When you commit new revisions, just take care not to hand edit or commit the top-level files in `config` containing `LB_*` variables, as these are build products, too, and are always cleaned up by `lb clean` and re-created with `lb config` via their respective `auto` scripts.

854

We've come to the end of our tutorial series. While many more kinds of customization are possible, even just using the few features explored in these simple examples, an almost infinite variety of different images can be created. The remaining examples in this section cover several other use cases drawn from the collected experiences of users of live systems.

855

##### 16.5 A VNC Kiosk Client

856

Use case: Create an image with live-build to boot directly to a VNC server.

857

Make a build directory and create an skeletal configuration inside it, disabling recommends to make a minimal system. And then create two initial package lists: the first one generated with a script provided by live-build named `Packages` (see Generated package lists), and the second one including xorg, gdm3, metacity and xvnc4viewer.

858

$ mkdir vnc-kiosk-client
$ cd vnc-kiosk-client
$ lb config --apt-recommends false
$ echo '! Packages Priority standard' > config/package-lists/standard.list.chroot
$ echo "xorg gdm3 metacity xtightvncviewer" > config/package-lists/my.list.chroot

859

As explained in Tweaking APT to save space you may need to re-add some recommended packages to make your image work properly.

860

An easy way to list recommends is using apt-cache. For example:

861

$ apt-cache depends live-config live-boot

862

In this example we found out that we had to re-include several packages recommended by live-config and live-boot: `user-setup` to make autologin work and `sudo` as an essential program to shutdown the system. Besides, it could be handy to add `live-tools` to be able to copy the image to RAM and `eject` to eventually eject the live medium. So:

863

$ echo "live-tools user-setup sudo eject" > config/package-lists/recommends.list.chroot

864

After that, create the directory `/etc/skel` in `config/includes.chroot` and put a custom `.xsession` in it for the default user that will launch metacity and start xvncviewer, connecting to port `5901` on a server at `192.168.1.2`:

865

$ mkdir -p config/includes.chroot/etc/skel
$ cat > config/includes.chroot/etc/skel/.xsession << EOF
#!/bin/sh
/usr/bin/metacity &
/usr/bin/xvncviewer 192.168.1.2:1
exit
EOF

866

Build the image:

867

# lb build

868

Enjoy.

869

##### 16.6 A minimal image for a 512MB USB key

870

Use case: Create a default image with some components removed in order to fit on a 512MB USB key with a little space left over to use as you see fit.

871

When optimizing an image to fit a certain media size, you need to understand the tradeoffs you are making between size and functionality. In this example, we trim only so much as to make room for additional material within a 512MB media size, but without doing anything to destroy the integrity of the packages contained within, such as the purging of locale data via the localepurge package, or other such "intrusive" optimizations. Of particular note, we use `--debootstrap-options` to create a minimal system from scratch and `--binary image hdd` to create an image that can be copied to a USB key.

872

$ lb config --binary-image hdd --apt-indices false --apt-recommends false --debootstrap-options "--variant=minbase" --firmware-chroot false --memtest none

873

To make the image work properly, we must re-add, at least, two recommended packages which are left out by the `--apt-recommends false` option. See Tweaking APT to save space

874

$ echo "user-setup sudo" > config/package-lists/recommends.list.chroot

875

Additionally, you'll want to have network access, so another two recommended packages need to be re-added:

876

$ echo "ifupdown isc-dhcp-client" >> config/package-lists/recommends.list.chroot

877

Now, build the image in the usual way:

878

# lb build 2>&1 | tee build.log

879

On the author's system at the time of writing this, the above configuration produced a 298MiB image. This compares favourably with the 380MiB image produced by the default configuration in Tutorial 1, when `--binary-image hdd` is added.

880

Leaving off APT's indices with `--apt-indices false` saves a fair amount of space, the tradeoff being that you need to do an `apt-get update` before using apt in the live system. Dropping recommended packages with `--apt-recommends false` saves some additional space, at the expense of omitting some packages you might otherwise expect to be there. `--debootstrap-options "--variant=minbase"` bootstraps a minimal system from the start. Not automatically including firmware packages with `--firmware-chroot false` saves some space too. And finally, `--memtest none` prevents the installation of a memory tester.

881

Note: A minimal system can also be achieved using hooks, like for example the `stripped.hook.chroot` hook found in `/usr/share/doc/live-build/examples/hooks`. It may shave off additional small amounts of space and produce an image of 277MiB. However, it does so by removal of documentation and other files from packages installed on the system. This violates the integrity of those packages and that, as the comment header warns, may have unforeseen consequences. That is why using a minimal debootstrap is the recommended way of achieving this goal.

882

##### 16.7 A localized GNOME desktop and installer

883

Use case: Create a GNOME desktop image, localized for Switzerland and including an installer.

884

We want to make an iso-hybrid image using our preferred desktop, in this case GNOME, containing all of the same packages that would be installed by the standard Debian installer for GNOME.

885

Our initial problem is the discovery of the names of the appropriate language tasks. Currently, live-build cannot help with this. While we might get lucky and find this by trial-and-error, there is a tool, `grep-dctrl`, which can be used to dig it out of the task descriptions in tasksel-data, so to prepare, make sure you have both of those things:

886

# apt-get install dctrl-tools tasksel-data

887

Now we can search for the appropriate tasks, first with:

888

$ grep-dctrl -FTest-lang de /usr/share/tasksel/descs/debian-tasks.desc -sTask
Task: german

889

By this command, we discover the task is called, plainly enough, german. Now to find the related tasks:

890

$ grep-dctrl -FEnhances german /usr/share/tasksel/descs/debian-tasks.desc -sTask
Task: german-desktop
Task: german-kde-desktop

891

At boot time we will generate the de_CH.UTF-8 locale and select the ch keyboard layout. Now let's put the pieces together. Recalling from Using metapackages that task metapackages are prefixed `task-`, we just specify these language boot parameters, then add standard priority packages and all our discovered task metapackages to our package list as follows:

892

$ mkdir live-gnome-ch
$ cd live-gnome-ch
$ lb config \
--bootappend-live "boot=live components locales=de_CH.UTF-8 keyboard-layouts=ch" \
--debian-installer live
$ echo '! Packages Priority standard' > config/package-lists/standard.list.chroot
$ echo task-gnome-desktop task-german task-german-desktop >> config/package-lists/desktop.list.chroot
$ echo debian-installer-launcher >> config/package-lists/installer.list.chroot

893

Note that we have included the debian-installer-launcher package to launch the installer from the live desktop.

894

# Anhang

895

# Style guide

896

#### 17. Style guide

897

##### 17.1 Guidelines for authors

898

This section deals with some general considerations to be taken into account when writing technical documentation for live-manual. They are divided into linguistic features and recommended procedures.

899

Note: Authors should first read Contributing to this document

900

###### 17.1.1 Linguistic features

901

- Use plain English

902

Keep in mind that a high percentage of your readers are not native speakers of English. So as a general rule try to use short, meaningful sentences, followed by a full stop.

903

This does not mean that you have to use a simplistic, naive style. It is a suggestion to try to avoid, as much as possible, complex subordinate sentences that make the text difficult to understand for non-native speakers of English.

904

- Variety of English

905

The most widely spread varieties of English are British and American so it is very likely that most authors will use either one or the other. In a collaborative environment, the ideal variety would be "International English" but it is very difficult, not to say impossible, to decide on which variety among all the existing ones, is the best to use.

906

We expect that different varieties may mix without creating misunderstandings but in general terms you should try to be coherent and before deciding on using British, American or any other English flavour at your discretion, please take a look at how other people write and try to imitate them.

907

- Be balanced

908

Do not be biased. Avoid including references to ideologies completely unrelated to live-manual. Technical writing should be as neutral as possible. It is in the very nature of scientific writing.

909

- Be politically correct

910

Try to avoid sexist language as much as possible. If you need to make references to the third person singular preferably use "they" rather than "he" or "she" or awkward inventions such as "s/he", "s(he)" and the like.

911

- Be concise

912

Go straight to the point and do not wander around aimlessly. Give as much information as necessary but do not give more information than necessary, this is to say, do not explain unnecessary details. Your readers are intelligent. Presume some previous knowledge on their part.

913

- Minimize translation work

914

Keep in mind that whatever you write will have to be translated into several other languages. This implies that a number of people will have to do an extra work if you add useless or redundant information.

915

- Be coherent

916

As suggested before, it is almost impossible to standardize a collaborative document into a perfectly unified whole. However, every effort on your side to write in a coherent way with the rest of the authors will be appreciated.

917

- Be cohesive

918

Use as many text-forming devices as necessary to make your text cohesive and unambiguous. (Text-forming devices are linguistic markers such as connectors).

919

- Be descriptive

920

It is preferable to describe the point in one or several paragraphs than merely using a number of sentences in a typical "changelog" style. Describe it! Your readers will appreciate it.

921

- Dictionary

922

Look up the meaning of words in a dictionary or encyclopedia if you do not know how to express certain concepts in English. But keep in mind that a dictionary can either be your best friend or can turn into your worst enemy if you do not know how to use it correctly.

923

English has the largest vocabulary that exists (with over one million words). Many of these words are borrowings from other languages. When looking up the meaning of words in a bilingual dictionary the tendency of a non-native speaker of English is to choose the one that sounds more similar in their mother tongue. This often turns into an excessively formal discourse which does not sound quite natural in English.

924

As a general rule, if a concept can be expressed using different synonyms, it is a good advice to choose the first word proposed by the dictionary. If in doubt, choosing words of Germanic origin (Usually monosyllabic words) is often the right thing to do. Be warned that these two techniques might produce a rather informal discourse but at least your choice of words will be of wide use and generally accepted.

925

Using a dictionary of collocations is recommended. They are extremely helpful when it comes to know which words usually occur together.

926

Again it is a good practice to learn from the work of others. Using a search engine to check how other authors use certain expressions may help a lot.

927

- False friends, idioms and other idiomatic expressions

928

Watch out for false friends. No matter how proficient you are in a foreign language you cannot help falling from time to time in the trap of the so called "false friends", words that look similar in two languages but whose meanings or uses might be completely different.

929

Try to avoid idioms as much as possible. "Idioms" are expressions that may convey a completely different meaning from what their individual words seem to mean. Sometimes, idioms might be difficult to understand even for native speakers of English!

930

- Avoid slang, abbreviations, contractions...

931

Even though you are encouraged to use plain, everyday English, technical writing belongs to the formal register of the language.

932

Try to avoid slang, unusual abbreviations that are difficult to understand and above all contractions that try to imitate the spoken language. Not to mention typical irc and family friendly expressions.

933

###### 17.1.2 Procedures

934

- Test before write

935

It is important that authors test their examples before adding them to live-manual to ensure that everything works as described. Testing on a clean chroot or VM can be a good starting point. Besides, it would be ideal if the tests were then carried out on different machines with different hardware to spot possible problems that may arise.

936

- Examples

937

When providing an example try to be as specific as you can. An example is, after all, just an example.

938

It is often better to use a line that only applies to a specific case than using abstractions that may confuse your readers. In this case you can provide a brief explanation of the effects of the proposed example.

939

There may be some exceptions when the example suggests using some potentially dangerous commands that, if misused, may cause data loss or other similar undesirable effects. In this case you should provide a thorough explanation of the possible side effects.

940

- External links

941

Links to external sites should only be used when the information on those sites is crucial when it comes to understanding a special point. Even so, try to use links to external sites as sparsely as possible. Internet links are likely to change from time to time resulting in broken links and leaving your arguments in an incomplete state.

942

Besides, people who read the manual offline will not have the chance to follow those links.

943

- Avoid branding and things that violate the license under which the manual is published

944

Try to avoid branding as much as possible. Keep in mind that other downstream projects might make use of the documentation you write. So you are complicating things for them if you add certain specific material.

945

live-manual is licensed under the GNU GPL. This has a number of implications that apply to the distribution of the material (of any kind, including copyrighted graphics or logos) that is published with it.

946

- Write a first draft, revise, edit, improve, redo if necessary

947

- Brainstorm!. You need to organize your ideas first in a logical sequence of events.

948

- Once you have somehow organized those ideas in your mind write a first draft.

949

- Revise grammar, syntax and spelling. Keep in mind that the proper names of the releases, such as trixie or sid, should not be capitalized when referred to as code names. In order to check the spelling you can run the "spell" target. i.e. `make spell`

950

- Improve your statements and redo any part if necessary.

951

- Chapters

952

Use the conventional numbering system for chapters and subtitles. e.g. 1, 1.1, 1.1.1, 1.1.2 ... 1.2, 1.2.1, 1.2.2 ... 2, 2.1 ... and so on. See markup below.

953

If you have to enumerate a series of steps or stages in your description, you can also use ordinal numbers: First, second, third ... or First, Then, After that, Finally ... Alternatively you can use bulleted items.

954

- Markup

955

And last but not least, live-manual uses SiSU to process the text files and produce a multiple format output. It is recommended to take a look at SiSU's manual to get familiar with its markup, or else type:

956

$ sisu --help markup

957

Here are some markup examples that may prove useful:

958

- For emphasis/bold text:

959

*{foo}* or !{foo}!

960

produces: foo or foo. Use it to emphasize certain key words.

961

- For italics:

962

/{foo}/

963

produces: foo. Use them e.g. for the names of Debian packages.

964

- For monospace:

965

#{foo}#

966

produces: `foo`. Use it e.g. for the names of commands. And also to highlight some key words or things like paths.

967

- For code blocks:

968

code{
$ foo
# bar
}code

969

produces:

970

$ foo
# bar

971

Use `code{` to open and `}code` to close the tags. It is important to remember to leave a space at the beginning of each line of code.

972

##### 17.2 Guidelines for translators

973

This section deals with some general considerations to be taken into account when translating the contents of live-manual.

974

As a general recommendation, translators should have read and understood the translation rules that apply to their specific languages. Usually, translation groups and mailing lists provide information on how to produce translated work that complies with Debian quality standards.

975

Note: Translators should also read Contributing to this document. In particular the section Translation

976

###### 17.2.1 Translation hints

977

- Comments

978

The role of the translator is to convey as faithfully as possible the meaning of words, sentences, paragraphs and texts as written by the original authors into their target language.

979

So they should refrain from adding personal comments or extra bits of information of their own. If they want to add a comment for other translators working on the same documents, they can leave it in the space reserved for that. That is, the header of the strings in the po files preceded by a number sign #. Most graphical translation programs can automatically handle those types of comments.

980

- TN, Translator's Note

981

It is perfectly acceptable however, to include a word or an expression in brackets in the translated text if, and only if, that makes the meaning of a difficult word or expression clearer to the reader. Inside the brackets the translator should make evident that the addition was theirs using the abbreviation "TN" or "Translator's Note".

982

- Impersonal sentences

983

Documents written in English make an extensive use of the impersonal form "you". In some other languages that do not share this characteristic, this might give the false impression that the original texts are directly addressing the reader when they are actually not doing so. Translators must be aware of that fact and reflect it in their language as accurately as possible.

984

- False friends

985

The trap of "false friends" explained before especially applies to translators. Double check the meaning of suspicious false friends if in doubt.

986

- Markup

987

Translators working initially with pot files and later on with po files will find many markup features in the strings. They can translate the text anyway, as long as it is translatable, but it is extremely important that they use exactly the same markup as the original English version.

988

- Code blocks

989

Even though the code blocks are usually untranslatable, including them in the translation is the only way to score a 100% complete translation. And even though it means more work at first because it might require the intervention of the translators if the code changes, it is the best way, in the long run, to identify what has already been translated and what has not when checking the integrity of the .po files.

990

- Newlines

991

The translated texts need to have the exact same newlines as the original texts. Be careful to press the "Enter" key or type \n if they appear in the original files. These newlines often appear, for instance, in the code blocks.

992

Make no mistake, this does not mean that the translated text needs to have the same length as the English version. That is nearly impossible.

993

- Untranslatable strings

994

Translators should never translate:

995

- The code names of releases (which should be written in lowercase)

996

- The names of programs

997

- The commands given as examples

998

- Metadata (often between colons :metadata:)

999

- Links

1000

- Paths