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Bazaar is a tool for helping people collaborate. It tracks the changes
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that you and other people make to a group of files - such as software
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source code - to give you snapshots of each stage of their evolution.
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Using that information, Bazaar can effortlessly merge your work with
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Tools like Bazaar are called version control systems (VCS) and have
14
long been popular with software developers. Bazaar's ease of use,
15
flexibility and simple setup make it ideal not only for software
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developers but also for other groups who work together on files and
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documents, such as technical writers, web designers and translators.
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This guide takes you through installing Bazaar and how to use it,
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whether on your own or with a team of other people. If you're already
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familiar with distributed version control and want to dive straight in,
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you may wish to skim this section and jump straight to
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Bazaar is a tool for helping people collaborate together. It does this by
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tracking how a group of files evolves and using that information to help
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people merge their changes together as safely as possible.
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In general, tools that do this are known as revision control systems or
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version control systems (VCS). In the past, VCS tools have been popular
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with software developers. In the future, VCS tools will undoubtedly also be
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important for other groups of people looking to collaborate together on
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files and documents, e.g. technical writers and translators.
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A brief history of version control systems
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18
------------------------------------------
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Version control tools have been evolving for several decades now. In
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simple terms, there have been 4 generations of tools:
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VCS tools have been evolving for several decades now. In simple terms,
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there have been 5 generations of tools:
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1. file versioning tools, e.g. SCCS, RCS
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2. tree versioning tools - central style, e.g. CVS
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3. tree versioning tools - central style, take two, e.g. Subversion
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4. tree versioning tools - distributed style, e.g. Bazaar.
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1. file versioning tools, e.g. SCCS, VCS
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2. tree versioning tools - central style, e.g. CVS
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3. tree versioning tools - central style, done right, e.g. Subversion
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4. tree versioning tools - distributed style, e.g. Arch
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5. tree versioning tools - distributed style, done right, e.g. Bazaar.
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The design and implementation of Bazaar builds on the lessons learned
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30
from all the previous generations of tools. In particular, Bazaar
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31
cleanly supports both the central and the distributed version
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control models so you can change models as it makes sense, without
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needing to change tools.
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Central vs distributed VCS
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35
--------------------------
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users need to connect to the server and *checkout* the files. This gives
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40
them a directory or *working tree* in which a person can make changes.
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To record or *commit* these changes, the user needs access to the central
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server and they need to ensure they have merged their work with the latest
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server and they need to unsure they have merged their work with the latest
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43
version stored before trying to commit. This approach is known as the
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The centralized model has proven useful over time but it can have some notable
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47
drawbacks. Firstly, a centralized VCS requires that one is able to connect
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to the server whenever one wants to do version control work. Secondly, the
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centralized model tightly links the act of **snapshotting** changes with the act
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of **publishing** those changes. This can be good in some circumstances but
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it has a negative influence on quality in others.
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centralized model tightly links the act of snapshotting changes with the act
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of publishing those changes. This can have a negative influence on quality.
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Distributed VCS tools let users and teams have multiple repositories
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rather than just a single central one. In Bazaar's case, the history is
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Decentralized VCS tools let users and teams have multiple repositories
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rather than just one central one. In Bazaar's case, the history is
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54
normally kept in the same place as the code that is being version controlled.
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55
This allows the user to commit their changes whenever it makes sense, even
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56
when offline. Network access is only required when publishing changes or
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57
when accessing changes in another location.
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In fact, using distributed VCS tools wisely can have advantages well
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beyond the obvious one of disconnected operations for developers.
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Other advantages include:
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* easier for developers to create experimental branches
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* easier ad-hoc collaboration with peers
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* less time required on mechanical tasks - more time for creativity
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* increased release management flexibility through the use of
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"feature-wide" commits
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* trunk quality and stability can be kept higher, making everyone's
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* in open source communities:
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* easier for non-core developers to create and maintain changes
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* easier for core developers to work with non-core developers and
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move them into the core
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* in companies, easier to work with distributed and outsourced teams.
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For a detailed look at the advantages of distributed VCS tools over
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centralized VCS tools, see http://bazaar-vcs.org/BzrWhy.
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For a detailed look at the advantages of decentralized VCS tools over
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centralized VCS tools, see http://bazaar-vcs.org/BzrWhy. In a nutshell,
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it comes down to this: distributed VCS tools make effective collaboration
62
easier, saving effort and increasing quality along the way.
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Key features of Bazaar
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68
While Bazaar is not the only distributed VCS tool around, it does have some
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69
notable features that make it an excellent choice for many teams and
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communities. A summary of these and comparisons with other VCS tools
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can be found on the Bazaar Wiki, http://bazaar-vcs.org.
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Of the many features, one in particular is worth highlighting:
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Bazaar is completely free software written in Python. As a result,
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it is easy to contribute improvements. If you wish to get involved,
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please see http://bazaar-vcs.org/BzrSupport.
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communities. These include:
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* it **Just Works** - a high focus on usability and performance
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* **adaptive** - cleanly supports many different ways of working together
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* **intelligent merging** that lets you collaborate without fear
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* **truly portable** across many operating systems including Windows
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* **renaming** of files and directories is properly supported
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* **safe with your data** - integrity is checked using cryptographic
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techniques and all changes can be digitally signed if required
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* **low administration**, e.g. automatic packing of repositories
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* **efficiently stores data** across branches in a flexible and safe way
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* an **open architecture and API** that makes it easy to integrate
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* a **large number of plugins** including bzr-svn and GUI front-ends
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* **excellent integration** with a range of companion tools and services
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including PQM, Bundle Buggy and Launchpad
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* **completely open source**
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* **commercial training and support** available from Canonical,
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the company that sponsors Ubuntu.
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While all of these are important, perhaps the greatest asset Bazaar has is
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an active and growing open source community behind it. Bazaar is completely
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free software written in Python so it is easy to contribute improvements.
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Our collective goal is to build and support a distributed VCS tool that
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developers love to use, a tool that helps them get their job done without
95
getting in their way. If you wish to get involved, please see
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http://bazaar-vcs.org/Community.
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This manual provides an easy to read introduction to Bazaar and how to use
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it effectively. It is recommended that all users read at least the rest of
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* explains the core concepts users need to know
117
* introduces some popular ways of using Bazaar to collaborate.
119
Chapters 2-6 provide a closer look at how to use Bazaar to complete
120
various tasks. It is recommended that most users read these in first-to-last
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order shortly after starting to use Bazaar. Chapter 7 and beyond provide
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additional information that helps you make the most of Bazaar once the core
123
functionality is understood. This material can be read when required and in
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If you are already familiar with other version control tools,
127
you may wish to get started quickly by reading the following documents:
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* `Bazaar in five minutes`_ - a mini-tutorial
131
* `Bazaar Quick Start Card`_ - a one page summary of commonly used commands.
133
In addition, the online help and `Bazaar User Reference`_ provide all the
134
details on the commands and options available.
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it effectively. If you are already familar with other version control tools,
104
you may wish to get started with Bazaar more quickly by reading the
105
following documents initially instead:
107
* `Bazaar in five minutes`_ - a mini-tutorial
109
* `Bazaar Quick Start Summary`_ - a one page summary of commonly used commands.
111
The online help and `Bazaar User Reference`_ are also particularly useful as
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they provide all the gory details on the commands and options available.
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.. _Bazaar in five minutes: ../mini-tutorial/index.html
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.. _Bazaar Quick Start Card: ../quick-reference/index.html
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.. _Bazaar User Reference: ../user-reference/index.html
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.. _Bazaar Quick Start Summary: ../quick-reference/quick-start-summary.svg
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.. _Bazaar User Reference: ../user-reference/bzr_man.html
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Either way, it is recommended that all users read the rest of this chapter
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* explains the core concepts users need to know
122
* introduces some popular ways of using Bazaar to collaborate.
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Remaining chapters provide a closer look at how to use Bazaar to complete
125
various tasks together with details on implementing some recommended
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128
We hope you find this manual useful. If you have suggestions on how it
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or the rest of Bazaar's documentation can be improved, please contact
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doc/en/user-guide/introducing_bazaar.txt
