2
2
.. into HTML or text. In the future we plan to extract the example commands
3
3
.. and automatically test them.
5
.. This text was previously on the wiki at http://bazaar.canonical.com/IntroductionToBzr
5
.. This text was previously on the wiki at
6
.. http://bazaar.canonical.com/IntroductionToBzr
6
7
.. but has been moved into the source tree so it can be kept in sync with
7
8
.. the source and possibly automatically checked.
13
Current for bzr-0.7pre, 2006-01-06.
14
Current for bzr-0.8, 2006-04
19
If you are already familiar with decentralized revision control, then please feel free to skip ahead to "Introducing Yourself to Bazaar-NG". If, on the other hand, you are familiar with revision control but not decentralized revision control, then please start at "How DRCS is different." Otherwise, get some coffee or tea, get comfortable and get ready to catch up.
20
If you are already familiar with decentralized revision control, then
21
please feel free to skip ahead to "Introducing Yourself to Bazaar". If,
22
on the other hand, you are familiar with revision control but not
23
decentralized revision control, then please start at "How DRCS is
24
different." Otherwise, get some coffee or tea, get comfortable and get
21
27
The Purposes of Revision Control
22
28
================================
24
Odds are that you have worked on some sort of textual data -- the sources to a program, web sites or the config files that Unix system administrators have to deal with in /etc. The chances are also good that you have made some sort of mistake that you deeply regretted. Perhaps you deleted the configuration file for your mailserver or perhaps mauled the source code for a pet project. Whatever happened, you have just deleted important information that you would desperately like to get back. If this has ever happened to you, then you are probably ready for Bazaar-NG.
26
Revision control systems (which I'll henceforth call RCS) such as Bazaar-NG give you the ability to track changes for a directory by turning it into something slightly more complicated than a directory that we call a **branch**. The branch not only stores how the directory looks right now, but also how it looked at various points in the past. Then, when you do something you wish you hadn't, you can restore the directory to the way it looked at some point in the past.
28
Revision control systems give users the ability to save changes to a branch by "committing a **revision**". The revision created is essentially a summary of the changes that were made since the last time the tree was saved.
30
These revisions have other uses as well. For example, one can comment revisions to record what the recent set of changes meant by providing an optional log message. Real life log messages include things like "Fixed the web template to close the table" and "Added sftp suppport. Fixes #595"
30
Odds are that you have worked on some sort of textual data -- the sources
31
to a program, web sites or the config files that Unix system
32
administrators have to deal with in /etc. The chances are also good that
33
you have made some sort of mistake that you deeply regretted. Perhaps you
34
deleted the configuration file for your mailserver or perhaps mauled the
35
source code for a pet project. Whatever happened, you have just deleted
36
important information that you would desperately like to get back. If this
37
has ever happened to you, then you are probably ready for Bazaar.
39
Revision control systems (which I'll henceforth call RCS) such as
40
Bazaar give you the ability to track changes for a directory by turning
41
it into something slightly more complicated than a directory that we call
42
a **branch**. The branch not only stores how the directory looks right
43
now, but also how it looked at various points in the past. Then, when you
44
do something you wish you hadn't, you can restore the directory to the way
45
it looked at some point in the past.
47
Revision control systems give users the ability to save changes to a
48
branch by "committing a **revision**". The revision created is essentially
49
a summary of the changes that were made since the last time the tree was
52
These revisions have other uses as well. For example, one can comment
53
revisions to record what the recent set of changes meant by providing an
54
optional log message. Real life log messages include things like "Fixed
55
the web template to close the table" and "Added sftp suppport. Fixes #595"
32
We keep these logs so that if later there is some sort of problem with sftp, we can figure out when the problem probably happened.
57
We keep these logs so that if later there is some sort of problem with
58
sftp, we can figure out when the problem probably happened.
34
60
How DRCS is Different
35
61
---------------------
37
Many Revision Control Systems (RCS) are stored on servers. If one wants to work on the code stored within an RCS, then one needs to connect to the server and "checkout" the code. Doing so gives one a directory in which a person can make changes and then commit. The RCS client then connects to the RCS server and stores the changes. This method is known as the centralized model.
39
The centralized model can have some drawbacks. A centralized RCS requires that one is able to connect to the server whenever one wants to do version control work. This can be a bit of a problem if your server on some other machine on the internet and you are not. Or, worse yet, you ''are'' on the internet but the server is missing!
41
Decentralized Revision Control Systems (which I'll call DRCS after this point) deal with this problem by keeping branches on the same machine as the client. In Bazaar-NG's case, the branch is kept in the same place as the code that is being version controlled. This allows the user to save his changes (**commit**) whenever he wants -- even if he is offline. The user only needs internet access when he wants to access the changes in someone else's branch that are somewhere else.
44
A common requirement that many people have is the need to keep track of the changes for a directory such as file and subdirectory changes. Performing this tracking by hand is a awkward process that over time becomes unwieldy. That is, until one considers version control tools such as Bazaar-NG. These tools automate the process of storing data by creating a **revision** of the directory tree whenever the user asks.
46
Revision control software such as Bazaar-NG can do much more than just storage and performing undo. For example, with Bazaar-NG developer can take the modifications in one branch of software and apply them to another, related, branch -- even if those changes exist in a branch owned by somebody else. This allows developers to cooperate without giving write access to repository.
48
Bazaar-NG remembers the ''ancestry'' of a revision: the previous revisions that it is based upon. A single revision may have more than one direct descendant, each with different changes, representing a divergence in the evolution of the tree. By branching, Bazaar-NG allows multiple people to cooperate on the evolution of a project, without all needing to work in strict lock-step. Branching can be useful even for a single developer.
50
Introducing yourself to Bazaar-NG
51
=================================
53
Bazaar-NG installs a single new command, **bzr**. Everything else is a subcommand of this. You can get some help with `bzr help`. There will be more in the future.
55
One function of a version control system is to keep track of who changed what. In a decentralized system, that requires an identifier for each author that is globally unique. Most people already have one of these: an email address. Bzr is smart enough to automatically generate an email address by looking up your username and hostname. If you don't like the guess that Bazaar-NG makes, then three options exist:
57
1. (**Bazaar-NG 0.6 and later**). Setting the email address in the
58
``~/.bazaar/bazaar.conf`` by adding the following lines. Please note that
63
Many Revision Control Systems (RCS) are stored on servers. If one wants to
64
work on the code stored within an RCS, then one needs to connect to the
65
server and "checkout" the code. Doing so gives one a directory in which a
66
person can make changes and then commit. The RCS client then connects to
67
the RCS server and stores the changes. This method is known as the
70
The centralized model can have some drawbacks. A centralized RCS requires
71
that one is able to connect to the server whenever one wants to do version
72
control work. This can be a bit of a problem if your server on some other
73
machine on the internet and you are not. Or, worse yet, you ''are'' on the
74
internet but the server is missing!
76
Decentralized Revision Control Systems (which I'll call DRCS after this
77
point) deal with this problem by keeping branches on the same machine as
78
the client. In Bazaar's case, the branch is kept in the same place as
79
the code that is being version controlled. This allows the user to save
80
his changes (**commit**) whenever he wants -- even if he is offline. The
81
user only needs internet access when he wants to access the changes in
82
someone else's branch that are somewhere else.
85
A common requirement that many people have is the need to keep track of
86
the changes for a directory such as file and subdirectory changes.
87
Performing this tracking by hand is a awkward process that over time
88
becomes unwieldy. That is, until one considers version control tools such
89
as Bazaar. These tools automate the process of storing data by creating
90
a **revision** of the directory tree whenever the user asks.
92
Revision control software such as Bazaar can do much more than just
93
storage and performing undo. For example, with Bazaar developer can
94
take the modifications in one branch of software and apply them to
95
another, related, branch -- even if those changes exist in a branch owned
96
by somebody else. This allows developers to cooperate without giving write
99
Bazaar remembers the ''ancestry'' of a revision: the previous revisions
100
that it is based upon. A single revision may have more than one direct
101
descendant, each with different changes, representing a divergence in the
102
evolution of the tree. By branching, Bazaar allows multiple people to
103
cooperate on the evolution of a project, without all needing to work in
104
strict lock-step. Branching can be useful even for a single developer.
106
Introducing yourself to Bazaar
107
==============================
109
Bazaar installs a single new command, **bzr**. Everything else is a
110
subcommand of this. You can get some help with `bzr help`. There will be
113
One function of a version control system is to keep track of who changed
114
what. In a decentralized system, that requires an identifier for each
115
author that is globally unique. Most people already have one of these: an
116
email address. Bzr is smart enough to automatically generate an email
117
address by looking up your username and hostname. If you don't like the
118
guess that Bazaar makes, then three options exist:
120
1. Set an email address via ``bzr whoami``. This is the simplest way.
121
To set a global identity, use::
123
% bzr whoami 'Your Name <email@example.com>'
125
If you'd like to use a different address for a specific branch, enter
126
the branch folder and use::
128
% bzr whoami --branch 'Your Name <email@example.com>'
130
1. Setting the email address in the
131
``~/.bazaar/bazaar.conf`` [1]_ by adding the following lines. Please note that
59
132
``[DEFAULT]`` is case sensitive::
62
135
email= Your Name <email@isp.com>
64
1. (**Bazaar-NG 0.6 and later**) Override the previous setting on a
65
branch by branch basis by creating a branch section in
66
``~/.bazaar/branches.conf`` by adding the following lines::
137
As above, you can override this settings on a branch by branch basis by
138
creating a branch section in ``~/.bazaar/locations.conf`` and adding the
68
141
[/the/directory/to/the/branch]
69
142
email=Your Name <email@isp.com>
71
144
1. Overriding the two previous options by setting the global environment
72
variable ``$BZREMAIL`` or ``$EMAIL`` (``$BZREMAIL`` will take precedence) to your full email address.
145
variable ``$BZREMAIL`` or ``$EMAIL`` (``$BZREMAIL`` will take precedence)
146
to your full email address.
148
.. [1] On Windows, the users configuration files can be found in the
149
application data directory. So instead of ``~/.bazaar/branch.conf``
150
the configuration file can be found as:
151
``C:\Documents and Settings\<username>\Application Data\Bazaar\2.0\branch.conf``.
152
The same is true for ``locations.conf``, ``ignore``, and the
153
``plugins`` directory.
77
History is by default stored in the .bzr directory of the branch. There will be a facility to store it in a separate repository, which may be remote. We create a new branch by running **bzr init** in an existing directory::
158
History is by default stored in the .bzr directory of the branch. There
159
will be a facility to store it in a separate repository, which may be
160
remote. We create a new branch by running **bzr init** in an existing
104
If you add the wrong file, simply use **bzr remove** to make it unversioned again. This does not delete the working copy.
190
If you add the wrong file, simply use **bzr remove** to make it
191
unversioned again. This does not delete the working copy.
109
All history is stored in a branch, which is just an on-disk directory containing control files. By default there is no separate repository or database as used in svn or svk. You can choose to create a repository if you want to (see the **bzr init-repo** command). You may wish to do this if you have very large branches, or many branches of a moderate sized project.
196
All history is stored in a branch, which is just an on-disk directory
197
containing control files. By default there is no separate repository or
198
database as used in svn or svk. You can choose to create a repository if
199
you want to (see the **bzr init-repo** command). You may wish to do this
200
if you have very large branches, or many branches of a moderate sized
111
203
You'll usually refer to branches on your computer's filesystem just by
112
204
giving the name of the directory containing the branch. bzr also supports
113
205
accessing branches over http, for example::
115
% bzr log http://bazaar-ng.org/bzr/bzr.dev/
207
% bzr log http://bazaar-vcs.org/bzr/bzr.dev/
117
By installing bzr plugins you can also access branches over the sftp or rsync protocols.
209
By installing bzr plugins you can also access branches over the sftp or
119
212
Reviewing changes
120
213
=================
122
Once you have completed some work, you will want to **commit** it to the version history. It is good to commit fairly often: whenever you get a new feature working, fix a bug, or improve some code or documentation. It's also a good practice to make sure that the code compiles and passes its test suite before committing, to make sure that every revision is a known-good state. You can also review your changes, to make sure you're committing what you intend to, and as a chance to rethink your work before you permanently record it.
215
Once you have completed some work, you will want to **commit** it to the
216
version history. It is good to commit fairly often: whenever you get a
217
new feature working, fix a bug, or improve some code or documentation.
218
It's also a good practice to make sure that the code compiles and passes
219
its test suite before committing, to make sure that every revision is a
220
known-good state. You can also review your changes, to make sure you're
221
committing what you intend to, and as a chance to rethink your work before
222
you permanently record it.
124
224
Two bzr commands are particularly useful here: **status** and **diff**.
160
264
% bzr diff --diff-options --side-by-side foo
266
Some projects prefer patches to show a prefix at the start of the path for
267
old and new files. The --prefix option can be used to provide such a prefix.
268
As a shortcut, ``bzr diff -p1`` produces a form that works with the
269
command ``patch -p1``.
162
271
Committing changes
163
272
==================
165
When the working tree state is satisfactory, it can be **committed** to the branch, creating a new revision holding a snapshot of that state.
274
When the working tree state is satisfactory, it can be **committed** to
275
the branch, creating a new revision holding a snapshot of that state.
170
The **commit** command takes a message describing the changes in the revision. It also records your userid, the current time and timezone, and the inventory and contents of the tree. The commit message is specified by the ''-m'' or ''--message'' option. You can enter a multi-line commit message; in most shells you can enter this just by leaving the quotes open at the end of the line.
280
The **commit** command takes a message describing the changes in the
281
revision. It also records your userid, the current time and timezone, and
282
the inventory and contents of the tree. The commit message is specified
283
by the ''-m'' or ''--message'' option. You can enter a multi-line commit
284
message; in most shells you can enter this just by leaving the quotes open
285
at the end of the line.
174
289
% bzr commit -m "added my first file"
176
You can also use the -F option to take the message from a file. Some people like to make notes for a commit message while they work, then review the diff to make sure they did what they said they did. (This file can also be useful when you pick up your work after a break.)
291
You can also use the -F option to take the message from a file. Some
292
people like to make notes for a commit message while they work, then
293
review the diff to make sure they did what they said they did. (This file
294
can also be useful when you pick up your work after a break.)
178
296
Message from an editor
179
297
======================
181
If you use neither the `-m` nor the `-F` option then bzr will open an editor for you to enter a message. The editor to run is controlled by your `$EDITOR` environment variable or (Post Bazaar-NG 0.6) email setting in . If you quit the editor without making any changes, the commit will be cancelled.
299
If you use neither the `-m` nor the `-F` option then bzr will open an
300
editor for you to enter a message. The editor to run is controlled by
301
your `$EDITOR` environment variable or
302
add `editor` to ~/.bazaar/bazaar.conf; `$BZR_EDITOR` will override
303
the above mentioned editor options. If you quit the editor without
304
making any changes, the commit will be cancelled.
321
488
Merging from related branches
322
489
=============================
324
If two branches have diverged (both have unique changes) then **bzr merge** is the appropriate command to use. Merge will automatically calculate the changes that exist in the branch you're merging from that are not in your branch and attempt to apply them in your branch.
491
If two branches have diverged (both have unique changes) then **bzr
492
merge** is the appropriate command to use. Merge will automatically
493
calculate the changes that exist in the branch you're merging from that
494
are not in your branch and attempt to apply them in your branch.
331
If there is a conflict during a merge, 3 files with the same basename are created. The filename of the common base is appended with .BASE, the filename of the file containing your changes is appended .THIS and the filename with the changes from the other tree is appended .OTHER.
332
Using a program such as kdiff3, you can now comfortably merge them into one file. To commit you have to rename it to the original basename and delete the other two files. As long as there exist files with .BASE, .THIS or .OTHER the commit command will complain.
501
If there is a conflict during a merge, 3 files with the same basename are
502
created. The filename of the common base is appended with .BASE, the
503
filename of the file containing your changes is appended .THIS and the
504
filename with the changes from the other tree is appended .OTHER.
505
Using a program such as kdiff3, you can now comfortably merge them into
506
one file. To commit you have to rename it to the original basename and
507
delete the other two files. As long as there exist files with .BASE, .THIS
508
or .OTHER the commit command will complain.
334
510
[**TODO**: explain conflict markers within files]
337
513
Publishing your branch
338
514
======================
339
You don't need a special server to publish a bzr branch, just a normal web server. Just mirror the files to your server, including the .bzr directory. One can push a branch (or the changes for a branch) by one of the following three methods:
341
* Rsync: rsync -avrz LOCALBRANCH servername.com/this/directory/here
342
* (Post 0.6): bzr push sftp://servername.com/this/directory/here (sftp://servername.com/this/directory/ must already exist)
343
* The push plugin that comes with BzrTools
516
You don't need a special server to publish a bzr branch, just a normal web
517
server. Just mirror the files to your server, including the .bzr
518
directory. One can push a branch (or the changes for a branch) by one of
519
the following three methods:
521
* Rsync: rsync -avrz LOCALBRANCH servername.com/this/directory/here
523
(or any other tool for publishing a directory to a web site.)
525
* bzr push sftp://servername.com/this/directory/here
527
(The directory that must already exist)
529
* The rspush plugin that comes with BzrTools
532
Moving changes between trees
533
============================
535
It happens to the best of us: sometimes you'll make changes in the wrong
536
tree. Maybe because you've accidentally started work in the wrong directory,
537
maybe because as you're working, the change turns out to be bigger than you
538
expected, so you start a new branch for it.
540
To move your changes from one tree to another, use
545
% bzr merge --uncommitted OLDDIR
547
This will apply all of the uncommitted changes you made in OLDDIR to NEWDIR.
548
It will not apply committed changes, even if they could be applied to NEWDIR
549
with a regular merge. The changes will remain in OLDDIR, but you can use **bzr
550
revert OLDDIR** to remove them, once you're satisfied with NEWDIR.
552
NEWDIR does not have to be a copy of OLDDIR, but they should be related.
553
The more different they are, the greater the chance of conflicts.
added
removed
doc/tutorial.txt
