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
6
.. http://bazaar.canonical.com/IntroductionToBzr
5
.. This text was previously on the wiki at http://bazaar.canonical.com/IntroductionToBzr
7
6
.. but has been moved into the source tree so it can be kept in sync with
8
7
.. the source and possibly automatically checked.
13
Current for bzr-0.7pre, 2006-01-06.
18
If you are already familiar with decentralized revision control, then
19
please feel free to skip ahead to "Introducing Yourself to Bazaar". If,
20
on the other hand, you are familiar with revision control but not
21
decentralized revision control, then please start at "How DRCS is
22
different." Otherwise, get some coffee or tea, get comfortable and get
25
The purpose of revision control
26
===============================
28
Odds are that you have worked on some sort of textual data -- the sources
29
to a program, web sites or the config files that Unix system
30
administrators have to deal with in /etc. The chances are also good that
31
you have made some sort of mistake that you deeply regretted. Perhaps you
32
deleted the configuration file for your mailserver or perhaps mauled the
33
source code for a pet project. Whatever happened, you have just deleted
34
important information that you would desperately like to get back. If this
35
has ever happened to you, then you are probably ready for Bazaar.
37
Revision control systems (which I'll henceforth call RCS) such as
38
Bazaar give you the ability to track changes for a directory by turning
39
it into something slightly more complicated than a directory that we call
40
a **branch**. The branch not only stores how the directory looks right
41
now, but also how it looked at various points in the past. Then, when you
42
do something you wish you hadn't, you can restore the directory to the way
43
it looked at some point in the past.
45
Revision control systems give users the ability to save changes to a
46
branch by "committing a **revision**". The revision created is essentially
47
a summary of the changes that were made since the last time the tree was
50
These revisions have other uses as well. For example, one can comment
51
revisions to record what the recent set of changes meant by providing an
52
optional log message. Real life log messages include things like "Fixed
53
the web template to close the table" and "Added sftp suppport. Fixes #595"
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.
21
The Purposes of Revision Control
22
================================
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"
55
We keep these logs so that if later there is some sort of problem with
56
sftp, we can figure out when the problem probably happened.
61
Many Revision Control Systems (RCS) are stored on servers. If one wants to
62
work on the code stored within an RCS, then one needs to connect to the
63
server and "checkout" the code. Doing so gives one a directory in which a
64
person can make changes and then commit. The RCS client then connects to
65
the RCS server and stores the changes. This method is known as the
68
The centralized model can have some drawbacks. A centralized RCS requires
69
that one is able to connect to the server whenever one wants to do version
70
control work. This can be a bit of a problem if your server is on some other
71
machine on the internet and you are not. Or, worse yet, you **are** on the
72
internet but the server is missing!
74
Decentralized Revision Control Systems (which I'll call DRCS after this
75
point) deal with this problem by keeping branches on the same machine as
76
the client. In Bazaar's case, the branch is kept in the same place as
77
the code that is being version controlled. This allows the user to save
78
his changes (**commit**) whenever he wants -- even if he is offline. The
79
user only needs internet access when he wants to access the changes in
80
someone else's branch that are somewhere else.
83
A common requirement that many people have is the need to keep track of
84
the changes for a directory such as file and subdirectory changes.
85
Performing this tracking by hand is a awkward process that over time
86
becomes unwieldy. That is, until one considers version control tools such
87
as Bazaar. These tools automate the process of storing data by creating
88
a **revision** of the directory tree whenever the user asks.
90
Revision control software such as Bazaar can do much more than just
91
storage and performing undo. For example, with Bazaar a developer can
92
take the modifications in one branch of software and apply them to a
93
related branch -- even if those changes exist in a branch owned by
94
somebody else. This allows developers to cooperate without giving
95
write access to the repository.
97
Bazaar remembers the ''ancestry'' of a revision: the previous revisions
98
that it is based upon. A single revision may have more than one direct
99
descendant, each with different changes, representing a divergence in the
100
evolution of the tree. By branching, Bazaar allows multiple people to
101
cooperate on the evolution of a project, without all needing to work in
102
strict lock-step. Branching can be useful even for a single developer.
104
Introducing yourself to Bazaar
105
==============================
107
Bazaar installs a single new command, **bzr**. Everything else is a
108
subcommand of this. You can get some help with ``bzr help``. Some arguments
109
are grouped in topics: ``bzr help topics`` to see which topics are available.
111
One function of a version control system is to keep track of who changed
112
what. In a decentralized system, that requires an identifier for each
113
author that is globally unique. Most people already have one of these: an
114
email address. Bazaar is smart enough to automatically generate an email
115
address by looking up your username and hostname. If you don't like the
116
guess that Bazaar makes, then three options exist:
118
1. Set an email address via ``bzr whoami``. This is the simplest way.
120
To set a global identity, use::
122
% bzr whoami "Your Name <email@example.com>"
124
If you'd like to use a different address for a specific branch, enter
125
the branch folder and use::
127
% bzr whoami --branch "Your Name <email@example.com>"
129
#. Setting the email address in the ``~/.bazaar/bazaar.conf`` [1]_ by
130
adding the following lines. Please note that ``[DEFAULT]`` is case
134
email=Your Name <email@isp.com>
136
As above, you can override this settings on a branch by branch basis
137
by creating a branch section in ``~/.bazaar/locations.conf`` and
138
adding the following lines::
140
[/the/path/to/the/branch]
141
email=Your Name <email@isp.com>
144
#. Overriding the two previous options by setting the global environment
145
variable ``$BZR_EMAIL`` or ``$EMAIL`` (``$BZR_EMAIL`` will take
146
precedence) 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.
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.
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
59
``[DEFAULT]`` is case sensitive::
62
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::
68
[/the/directory/to/the/branch]
69
email=Your Name <email@isp.com>
71
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.
158
History is by default stored in the .bzr directory of the branch. In a
159
future version of Bazaar, there will be a facility to store it in a
160
separate repository, which may be remote.
162
We create a new branch by running ``bzr init`` in an existing 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::
176
As with CVS, there are three classes of file: unknown, ignored, and
177
versioned. The **add** command makes a file versioned: that is, changes
178
to it will be recorded by the system::
91
As for CVS, there are three classes of file: unknown, ignored, and versioned. The **add** command makes a file versioned: that is, changes to it will be recorded by the system::
180
93
% echo 'hello world' > hello.txt
184
99
% bzr add hello.txt
191
If you add the wrong file, simply use ``bzr remove`` to make it
192
unversioned again. This does not delete the working copy in this case,
193
though it may in others [2]_.
195
.. [2] ``bzr remove`` will remove the working copy if it is currently
196
versioned, but has no changes from the last committed version. You
197
can force the file to always be kept with the ``--keep`` option to
198
``bzr remove``, or force it to always be deleted with ``--force``.
104
If you add the wrong file, simply use **bzr remove** to make it unversioned again. This does not delete the working copy.
203
All history is stored in a branch, which is just an on-disk directory
204
containing control files. By default there is no separate repository or
205
database as used in svn or svk. You can choose to create a repository if
206
you want to (see the ``bzr init-repo`` command). You may wish to do this
207
if you have very large branches, or many branches of a moderately sized
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.
210
111
You'll usually refer to branches on your computer's filesystem just by
211
112
giving the name of the directory containing the branch. bzr also supports
212
accessing branches over http and sftp, for example::
214
% bzr log http://bazaar-vcs.org/bzr/bzr.dev/
215
% bzr log sftp://bazaar-vcs.org/bzr/bzr.dev/
217
By installing bzr plugins you can also access branches using the rsync
220
See the `Publishing your branch`_ section for more about how to put your
221
branch at a given location.
113
accessing branches over http, for example::
115
% bzr log http://bazaar-ng.org/bzr/bzr.dev/
117
By installing bzr plugins you can also access branches over the sftp or rsync protocols.
223
119
Reviewing changes
224
120
=================
226
Once you have completed some work, you will want to **commit** it to the
227
version history. It is good to commit fairly often: whenever you get a
228
new feature working, fix a bug, or improve some code or documentation.
229
It's also a good practice to make sure that the code compiles and passes
230
its test suite before committing, to make sure that every revision is a
231
known-good state. You can also review your changes, to make sure you're
232
committing what you intend to, and as a chance to rethink your work before
233
you permanently record it.
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.
235
124
Two bzr commands are particularly useful here: **status** and **diff**.
247
``bzr status`` hides "boring" files that are either unchanged or ignored.
248
The status command can optionally be given the name of some files or
249
directories to check.
136
By default **bzr status** hides "boring" files that are either unchanged or ignored. To see them too, use the --all option. The status command can optionally be given the name of some files or directories to check.
254
The **diff** command shows the full text of changes to all files as a
255
standard unified diff. This can be piped through many programs such as
256
''patch'', ''diffstat'', ''filterdiff'' and ''colordiff''::
141
The **diff** command shows the full text of changes to all files as a standard unified diff. This can be piped through many programs such as ''patch'', ''diffstat'', ''filterdiff'' and ''colordiff''::
259
=== added file 'hello.txt'
260
--- hello.txt 1970-01-01 00:00:00 +0000
261
+++ hello.txt 2005-10-18 14:23:29 +0000
144
*** added file 'hello.txt'
266
With the ``-r`` option, the tree is compared to an earlier revision, or
151
With the ''-r'' option, the tree is compared to an earlier revision, or
267
152
the differences between two versions are shown::
269
154
% bzr diff -r 1000.. # everything since r1000
270
155
% bzr diff -r 1000..1100 # changes from 1000 to 1100
272
The ``--diff-options`` option causes bzr to run the external diff program,
157
The --diff-options option causes bzr to run the external diff program,
273
158
passing options. For example::
275
160
% bzr diff --diff-options --side-by-side foo
277
Some projects prefer patches to show a prefix at the start of the path
278
for old and new files. The ``--prefix`` option can be used to provide
280
As a shortcut, ``bzr diff -p1`` produces a form that works with the
281
command ``patch -p1``.
284
162
Committing changes
285
163
==================
287
When the working tree state is satisfactory, it can be **committed** to
288
the branch, creating a new revision holding a snapshot of that state.
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.
293
The **commit** command takes a message describing the changes in the
294
revision. It also records your userid, the current time and timezone, and
295
the inventory and contents of the tree. The commit message is specified
296
by the ``-m`` or ``--message`` option. You can enter a multi-line commit
297
message; in most shells you can enter this just by leaving the quotes open
298
at the end of the line.
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.
302
174
% bzr commit -m "added my first file"
304
You can also use the ``-F`` option to take the message from a file. Some
305
people like to make notes for a commit message while they work, then
306
review the diff to make sure they did what they said they did. (This file
307
can also be useful when you pick up your work after a break.)
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.)
309
178
Message from an editor
310
----------------------
312
If you use neither the ``-m`` nor the ``-F`` option then bzr will open an
313
editor for you to enter a message. The editor to run is controlled by
314
your ``$VISUAL`` or ``$EDITOR`` environment variable, which can be overridden
315
by the ``editor`` setting in ``~/.bazaar/bazaar.conf``; ``$BZR_EDITOR`` will
316
override either of the above mentioned editor options. If you quit the
317
editor without making any changes, the commit will be cancelled.
319
The file that is opened in the editor contains a horizontal line. The part
320
of the file below this line is included for information only, and will not
321
form part of the commit message. Below the separator is shown the list of
322
files that are changed in the commit. You should write your message above
323
the line, and then save the file and exit.
325
If you would like to see the diff that will be committed as you edit the
326
message you can use the ``--show-diff`` option to ``commit``. This will include
327
the diff in the editor when it is opened, below the separator and the
328
information about the files that will be committed. This means that you can
329
read it as you write the message, but the diff itself wont be seen in the
330
commit message when you have finished. If you would like parts to be
331
included in the message you can copy and paste them above the separator.
179
======================
181
If you use neither the `-m` nor the `-F` option then bzr will open an editor for you to enter a message. The editor to run is controlled by your `$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.
378
214
If a glob contains a slash, it is matched against the whole path from the
379
215
top of the tree; otherwise it is matched against only the filename. So
380
216
the previous example ignores files with extension ``.o`` in all
381
subdirectories, but this example ignores only ``config.h`` at the top level
217
subdirectories, but this example ignores only config.h at the top level
382
218
and HTML files in ``doc/``::
387
To get a list of which files are ignored and what pattern they matched,
388
use ``bzr ignored``::
223
To get a list of which files are ignored and what pattern they matched, use ''bzr ignored''::
391
226
config.h ./config.h
394
It is OK to have either an ignore pattern match a versioned file, or to
395
add an ignored file. Ignore patterns have no effect on versioned files;
396
they only determine whether unversioned files are reported as unknown or
229
It is OK to have either an ignore pattern match a versioned file, or to add an ignored file. Ignore patterns have no effect on versioned files; they only determine whether unversioned files are reported as unknown or ignored.
399
The ``.bzrignore`` file should normally be versioned, so that new copies
400
of the branch see the same patterns::
231
The ''.bzrignore'' file should normally be versioned, so that new copies of the branch see the same patterns::
402
233
% bzr add .bzrignore
403
234
% bzr commit -m "Add ignore patterns"
409
There are some ignored files which are not project specific, but more user
410
specific. Things like editor temporary files, or personal temporary files.
411
Rather than add these ignores to every project, bzr supports a global
412
ignore file in ``~/.bazaar/ignore`` [1]_. It has the same syntax as the
413
per-project ignore file.
416
237
Examining history
417
238
=================
422
The ``bzr log`` command shows a list of previous revisions. The ``bzr log
423
--forward`` command does the same in chronological order to get most
424
recent revisions printed at last.
243
The **bzr log** command shows a list of previous revisions. The **bzr log --forward** command does the same in chronological order to get most recent revisions printed at last.
426
As with ``bzr diff``, ``bzr log`` supports the ``-r`` argument::
245
As with bzr diff, bzr log supports the -r argument::
428
247
% bzr log -r 1000.. # Revision 1000 and everything after it
429
% bzr log -r ..1000 # Everything up to and including r1000
248
% bzr log -r ..1000 # Everything up to and including revision % 1000
430
249
% bzr log -r 1000..1100 # changes from 1000 to 1100
431
250
% bzr log -r 1000 # The changes in only revision 1000
521
321
Merging from related branches
522
322
=============================
524
If two branches have diverged (both have unique changes) then ``bzr
525
merge`` is the appropriate command to use. Merge will automatically
526
calculate the changes that exist in the branch you're merging from that
527
are not in your branch and attempt to apply them in your branch.
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.
534
If there is a conflict during a merge, 3 files with the same basename
535
are created. The filename of the common base is appended with ".BASE",
536
the filename of the file containing your changes is appended with
537
".THIS" and the filename with the changes from the other tree is
538
appended with ".OTHER". Using a program such as kdiff3, you can now
539
comfortably merge them into one file. In order to commit you have to
540
rename the merged file (".THIS") to the original file name. To
541
complete the conflict resolution you must use the resolve command,
542
which will remove the ".OTHER" and ".BASE" files. As long as there
543
exist files with .BASE, .THIS or .OTHER the commit command will
548
% kdiff3 file.BASE file.OTHER file.THIS
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.
552
334
[**TODO**: explain conflict markers within files]
555
337
Publishing your branch
556
338
======================
558
You don't need a special server to publish a bzr branch, just a normal web
559
server. Just mirror the files to your server, including the .bzr
560
directory. One can push a branch (or the changes for a branch) by one of
561
the following three methods:
563
* The best method is to use bzr itself to do it.
567
% bzr push sftp://servername.com/path/to/directory
569
(The destination directory must already exist unless the
570
``--create-prefix`` option is used.)
572
* Another option is the ``rspush`` plugin that comes with BzrTools, which
573
uses rsync to push the changes to the revision history and the working
576
* You can also copy the files around manually, by sending a tarball, or using
577
rsync, or other related file transfer methods. This is usually less safe
578
than using ``push``, but may be faster or easier in some situations.
581
Moving changes between trees
582
============================
584
It happens to the best of us: sometimes you'll make changes in the wrong
585
tree. Maybe because you've accidentally started work in the wrong directory,
586
maybe because as you're working, the change turns out to be bigger than you
587
expected, so you start a new branch for it.
589
To move your changes from one tree to another, use
594
% bzr merge --uncommitted OLDDIR
596
This will apply all of the uncommitted changes you made in OLDDIR to NEWDIR.
597
It will not apply committed changes, even if they could be applied to NEWDIR
598
with a regular merge. The changes will remain in OLDDIR, but you can use ``bzr
599
revert OLDDIR`` to remove them, once you're satisfied with NEWDIR.
601
NEWDIR does not have to be a copy of OLDDIR, but they should be related.
602
The more different they are, the greater the chance of conflicts.
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)
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* The push plugin that comes with BzrTools
added
removed
tutorial.txt
