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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
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long been popular with software developers. Bazaar's ease of use,
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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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A brief history of version control systems
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------------------------------------------
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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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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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The design and implementation of Bazaar builds on the lessons learned
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from all the previous generations of tools. In particular, Bazaar
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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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--------------------------
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Many traditional VCS tools require a central server which provides the
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change history or *repository* for a tree of files. To work on the files,
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users need to connect to the server and *checkout* the files. This gives
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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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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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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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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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normally kept in the same place as the code that is being version controlled.
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This allows the user to commit their changes whenever it makes sense, even
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when offline. Network access is only required when publishing changes or
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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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Key features of Bazaar
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----------------------
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While Bazaar is not the only distributed VCS tool around, it does have some
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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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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
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* introduces some popular ways of using Bazaar to collaborate.
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Chapters 2-6 provide a closer look at how to use Bazaar to complete
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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
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functionality is understood. This material can be read when required and in
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If you are already familar with other version control tools,
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you may wish to get started quickly by reading the following documents:
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* `Bazaar in five minutes`_ - a mini-tutorial
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* `Bazaar Quick Start Card`_ - a one page summary of commonly used commands.
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In addition, the online help and `Bazaar User Reference`_ provide all the
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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/quick-start-summary.svg
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.. _Bazaar User Reference: ../user-reference/bzr_man.html
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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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us on the mailing list, bazaar@lists.canonical.com.
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