1
.. This file is in Python ReStructuredText format - it can be formatted
2
.. into HTML or text. In the future we plan to extract the example commands
3
.. and automatically test them.
5
.. This text was previously on the wiki at
6
.. http://bazaar.canonical.com/IntroductionToBzr
7
.. but has been moved into the source tree so it can be kept in sync with
8
.. the source and possibly automatically checked.
14
Current for bzr-0.8, 2006-04
5
current for bzr 0.0.6pre, July 2005
8
*Note:* This tutorial is a work in
9
progress, and describes code that is itself still evolving.
10
If you have comments on either the design or the tutorial,
11
please send them to the bazaar-ng@lists.canonical.com mailing list.
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
27
The Purposes of Revision Control
28
================================
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"
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.
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``. Some arguments
111
are grouped in topics: ``bzr help topics`` to see which topics are available.
112
There will be more in the future.
114
One function of a version control system is to keep track of who changed
115
what. In a decentralized system, that requires an identifier for each
116
author that is globally unique. Most people already have one of these: an
117
email address. Bzr is smart enough to automatically generate an email
118
address by looking up your username and hostname. If you don't like the
119
guess that Bazaar makes, then three options exist:
121
1. Set an email address via ``bzr whoami``. This is the simplest way.
122
To set a global identity, use::
124
% bzr whoami 'Your Name <email@example.com>'
126
If you'd like to use a different address for a specific branch, enter
127
the branch folder and use::
129
% bzr whoami --branch 'Your Name <email@example.com>'
131
1. Setting the email address in the
132
``~/.bazaar/bazaar.conf`` [1]_ by adding the following lines. Please note that
133
``[DEFAULT]`` is case sensitive::
136
email= Your Name <email@isp.com>
138
As above, you can override this settings on a branch by branch basis by
139
creating a branch section in ``~/.bazaar/locations.conf`` and adding the
142
[/the/directory/to/the/branch]
143
email=Your Name <email@isp.com>
145
1. Overriding the two previous options by setting the global environment
146
variable ``$BZREMAIL`` or ``$EMAIL`` (``$BZREMAIL`` will take precedence)
147
to your full email address.
149
.. [1] On Windows, the users configuration files can be found in the
150
application data directory. So instead of ``~/.bazaar/branch.conf``
151
the configuration file can be found as:
152
``C:\Documents and Settings\<username>\Application Data\Bazaar\2.0\branch.conf``.
153
The same is true for ``locations.conf``, ``ignore``, and the
154
``plugins`` directory.
18
Bazaar-NG is a version control tool. It manages trees of files and subdirectories. In particular, it records *revisions* of trees, representing their state at a particular point in time, and information about those revisions and their relationships. Recording and retrieving tree revisions is useful in several ways if you are writing software or documents or doing similar creative work.
20
* Keeping previous revisions lets you go back if you make a mistake or want to check your work. It acts as a high-level unlimited undo.
22
* By recording comments on every revision, you produce an annotated history of the project, describing what, who, why, and when.
24
* Using a version control tool can be an aid to thinking about a project: getting to a stable state at regular intervals and then writing a description of what you did is an easy way to stay organized and on track.
26
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.
27
By branching, Bazaar-NG allows multiple people to cooperate on the evolution of a project, without all needing to work in strict
28
lock-step. Branching can be useful even for a single developer.
30
Bazaar-NG installs a single new command,
31
*bzr*. Everything else is a subcommand of this. You can get
32
some help with ``bzr help``. There will be more in the future.
36
Introducing yourself to bzr
37
===========================
39
One function of a version control system is to keep track of who
40
changed what. In a distributed system that requires an identifier for
41
each author that is globally unique. Most people already have one of
42
these: an email address.
44
[after 0.0.4] To tell bzr which email address to use, put it in the file
45
``$HOME/.bzr.conf/email``, or the environment variable ``$BZREMAIL``.
46
If neither of these are set, bzr will use the ``$EMAIL``
47
variable, or use your username and hostname.
49
To check this has taken effect, or if you forget your own name, use
50
the ``whoami`` ("who am i?") command::
54
Some people want to avoid sharing their email address so as not to
55
get spam. bzr will never
56
disclose your email address unless you tell it to by publishing an
57
archive or transmiting a changeset. It's recommended that you do use
58
a real address, so that people can contact you about your work, but
59
it's not required. You can use an address which is obfuscated, which
60
bounces, or which goes through an anti-spam service such as spamgourmet.com.
159
History is by default stored in the .bzr directory of the branch. There
160
will be a facility to store it in a separate repository, which may be
161
remote. We create a new branch by running **bzr init** in an existing
68
History is by default stored in the .bzr directory of the branch.
69
There will be a facility to store it in a separate repository, which
70
may be remote. We create a new branch by running *bzr init* in
71
an existing directory::
169
79
/home/mbp/work/bzr.test/tutorial
176
86
As for 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::
87
versioned. The *add* command makes a file versioned: that is,
88
changes to it will be recorded by the system::
180
90
% echo 'hello world' > hello.txt
95
% bzr add -v 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.
197
All history is stored in a branch, which is just an on-disk directory
198
containing control files. By default there is no separate repository or
199
database as used in svn or svk. You can choose to create a repository if
200
you want to (see the **bzr init-repo** command). You may wish to do this
201
if you have very large branches, or many branches of a moderate sized
204
You'll usually refer to branches on your computer's filesystem just by
205
giving the name of the directory containing the branch. bzr also supports
206
accessing branches over http, for example::
208
% bzr log http://bazaar-vcs.org/bzr/bzr.dev/
210
By installing bzr plugins you can also access branches over the sftp or
100
If you add the wrong file, simply use ``bzr remove`` to make
101
it unversioned again. This does not delete the working copy.
213
104
Reviewing changes
214
105
=================
216
Once you have completed some work, you will want to **commit** it to the
217
version history. It is good to commit fairly often: whenever you get a
218
new feature working, fix a bug, or improve some code or documentation.
219
It's also a good practice to make sure that the code compiles and passes
220
its test suite before committing, to make sure that every revision is a
221
known-good state. You can also review your changes, to make sure you're
222
committing what you intend to, and as a chance to rethink your work before
223
you permanently record it.
225
Two bzr commands are particularly useful here: **status** and **diff**.
230
The **status** command tells you what changes have been made to the
231
working directory since the last revision::
107
Once you have completed some work, you will want to *commit*
108
it to the version history. It is good to commit fairly often:
109
whenever you get a new feature working, fix a bug, or improve some
110
code or documentation. It's also a good practice to make sure that
111
the code compiles and passes its test suite before committing, to make
112
sure that every revision is a known-good state. You can also review
113
your changes, to make sure you're committing what you intend to, and
114
as a chance to rethink your work before you permanently record it.
116
Two bzr commands are particularly useful here: *status* and
117
*diff*. The *status* command
118
shows a listing with one line per file, indicating whether it has been
119
Added, Deleted, Modified, or Renamed in the current revision. Unknown
120
files are shown as '?'. With the ``--all`` option, the status
121
command also shows unmodified versioned files as '.', and ignored
237
By default **bzr status** hides "boring" files that are either unchanged
238
or ignored. To see them too, use the --all option. The status command
239
can optionally be given the name of some files or directories to check.
244
The **diff** command shows the full text of changes to all files as a
245
standard unified diff. This can be piped through many programs such as
246
''patch'', ''diffstat'', ''filterdiff'' and ''colordiff''::
127
The *diff* command shows the full text of changes to all
128
files as a standard unified diff. This can be piped through many
129
programs such as ``patch``, ``diffstat``,
130
``filterdiff`` and ``colordiff``::
249
133
*** added file 'hello.txt'
256
With the ''-r'' option, the tree is compared to an earlier revision, or
257
the differences between two versions are shown::
259
% bzr diff -r 1000.. # everything since r1000
260
% bzr diff -r 1000..1100 # changes from 1000 to 1100
262
The --diff-options option causes bzr to run the external diff program,
263
passing options. For example::
265
% bzr diff --diff-options --side-by-side foo
267
Some projects prefer patches to show a prefix at the start of the path for
268
old and new files. The --prefix option can be used to provide such a prefix.
269
As a shortcut, ``bzr diff -p1`` produces a form that works with the
270
command ``patch -p1``.
139
With the ``-r`` option, the tree is compared to an earlier
142
[TODO: options to run external diff; to get context diff or other
143
formats; to diff only selected files; to compare two historical
272
148
Committing changes
273
149
==================
275
When the working tree state is satisfactory, it can be **committed** to
276
the branch, creating a new revision holding a snapshot of that state.
281
The **commit** command takes a message describing the changes in the
282
revision. It also records your userid, the current time and timezone, and
283
the inventory and contents of the tree. The commit message is specified
284
by the ''-m'' or ''--message'' option. You can enter a multi-line commit
285
message; in most shells you can enter this just by leaving the quotes open
286
at the end of the line.
151
When the working tree state is satisfactory, it can be
152
*committed* to the branch, creating a new revision holding a
153
snapshot of that state.
155
The ``commit`` command takes a message describing the changes
156
in the revision. It also records your userid, the current time and
157
timezone, and the inventory and contents of the tree. The commit
158
message is specified by the ``-m`` or ``--message`` option.
159
You can enter a multi-line commit message; in most shells you can
160
enter this just by leaving the quotes open at the end of the line. ::
290
162
% bzr commit -m "added my first file"
292
You can also use the -F option to take the message from a file. Some
293
people like to make notes for a commit message while they work, then
294
review the diff to make sure they did what they said they did. (This file
295
can also be useful when you pick up your work after a break.)
297
Message from an editor
298
======================
300
If you use neither the `-m` nor the `-F` option then bzr will open an
301
editor for you to enter a message. The editor to run is controlled by
302
your `$VISUAL` or `$EDITOR` environment variable, which can be overridden
303
by the `editor` setting in to ~/.bazaar/bazaar.conf; `$BZR_EDITOR` will
304
override either of the above mentioned editor options. If you quit the
305
editor without making any changes, the commit will be cancelled.
310
If you give file or directory names on the commit command line then only
311
the changes to those files will be committed. For example::
313
% bzr commit -m "documentation fix" commit.py
315
By default bzr always commits all changes to the tree, even if run from a
316
subdirectory. To commit from only the current directory down, use::
164
[TODO: commit message interactively, through an editor or from a
167
[TODO: commit only selected files, including renamed/added/deleted
321
172
Removing uncommitted changes
322
173
============================
324
175
If you've made some changes and don't want to keep them, use the
325
**revert** command to go back to the previous head version. It's a good
326
idea to use **bzr diff** first to see what will be removed. By default the
327
revert command reverts the whole tree; if file or directory names are
328
given then only those ones will be affected. **revert** also clears the
329
list of pending merges revisions.
176
``revert`` command to go back to the previous head version. It's a
177
good idea to use ``bzr diff`` first to see what will be removed.
178
By default the revert command reverts the whole tree; if file or
179
directory names are given then only those ones will be affected.
180
revert also clears the list of pending merges revisions.
334
Many source trees contain some files that do not need to be versioned,
335
such as editor backups, object or bytecode files, and built programs. You
336
can simply not add them, but then they'll always crop up as unknown files.
337
You can also tell bzr to ignore these files by adding them to a file
338
called ''.bzrignore'' at the top of the tree.
189
Many source trees contain some files that do not need to be
190
versioned, such as editor backups, object or bytecode files, and built
191
programs. You can simply not add them, but then they'll always crop
192
up as unknown files. You can also tell bzr to ignore these files by
193
adding them to a file called ``.bzrignore`` at the top of the
340
This file contains a list of file wildcards (or "globs"), one per line.
341
Typical contents are like this::
196
This file contains a list of file wildcards (or "globs"), one
197
per line. Typical contents are like this::
348
If a glob contains a slash, it is matched against the whole path from the
349
top of the tree; otherwise it is matched against only the filename. So
350
the previous example ignores files with extension ``.o`` in all
351
subdirectories, but this example ignores only config.h at the top level
352
and HTML files in ``doc/``::
204
If a glob contains a slash, it is matched against the whole path
205
from the top of the tree; otherwise it is matched against only the
206
filename. So the previous example ignores ``*.o`` in all
207
subdirectories, but this example ignores only config.h at the top
208
level and HTML files in ``doc/``::
357
To get a list of which files are ignored and what pattern they matched,
358
use ''bzr ignored''::
213
To get a list of which files are ignored and what pattern they matched, use ``bzr ignored``::
364
It is OK to have either an ignore pattern match a versioned file, or to
365
add an ignored file. Ignore patterns have no effect on versioned files;
366
they only determine whether unversioned files are reported as unknown or
369
The ``.bzrignore`` file should normally be versioned, so that new copies
370
of the branch see the same patterns::
219
It is OK to have an ignore pattern match a versioned file, or to
220
add an ignored file. Ignore patterns have no effect on versioned
221
files; they only determine whether unversioned files are reported as
224
The ``.bzrignore`` file should normally be versioned, so that new
225
copies of the branch see the same patterns::
372
227
% bzr add .bzrignore
373
228
% bzr commit -m "Add ignore patterns"
379
There are some ignored files which are not project specific, but more user
380
specific. Things like editor temporary files, or personal temporary files.
381
Rather than add these ignores to every project, bzr supports a global
382
ignore file in ``~/.bazaar/ignore`` [1]_. It has the same syntax as the
383
per-project ignore file.
386
231
Examining history
387
232
=================
392
The **bzr log** command shows a list of previous revisions. The **bzr log
393
--forward** command does the same in chronological order to get most
394
recent revisions printed at last.
396
As with bzr diff, bzr log supports the -r argument::
398
% bzr log -r 1000.. # Revision 1000 and everything after it
399
% bzr log -r ..1000 # Everything up to and including r1000
400
% bzr log -r 1000..1100 # changes from 1000 to 1100
401
% bzr log -r 1000 # The changes in only revision 1000
237
The ``log`` command shows a list of previous revisions.
404
240
Branch statistics
405
241
=================
407
The **bzr info** command shows some summary information about the working
408
tree and the branch history.
243
The ``bzr info`` command shows some summary information about
244
the working tree and the branch history.
411
247
Versioning directories
412
248
======================
414
bzr versions files and directories in a way that can keep track of renames
415
and intelligently merge them::
250
bzr versions files and directories in a way that can keep track of
251
renames and intelligently merge them::
418
254
% echo 'int main() {}' > src/simple.c
259
% bzr add src/simple.c
428
265
Deleting and removing files
429
266
===========================
431
You can delete files or directories by just deleting them from the working
432
directory. This is a bit different to CVS, which requires that you also
435
**bzr remove** makes the file un-versioned, but does not delete
436
the working copy. This is useful when you add the wrong file, or decide
437
that a file should actually not be versioned.
268
You can delete files or directories by just deleting them from the
269
working directory. This is a bit different to CVS, which requires
270
that you also do *cvs remove*.
272
*bzr remove* makes the file un-versioned, but does not
273
delete the working copy. This is useful when you add the wrong file,
274
or decide that a file should actually not be versioned. ::
442
277
% bzr remove -v hello.txt
452
If you remove the wrong file by accident, you can use **bzr revert** to
459
Often rather than starting your own project, you will want to submit a
460
change to an existing project. You can get a copy of an existing branch
461
by copying its directory, expanding a tarball, or by a remote copy using
462
something like rsync. You can also use bzr to fetch a copy. Because this
463
new copy is potentially a new branch, the command is called *branch*::
288
Often rather than starting your own project, you will want to
289
submit a change to an existing project. You can get a copy of an
290
existing branch by copying its directory, expanding a tarball, or by a
291
remote copy using something like rsync. You can also use bzr to fetch
292
a copy. Because this new copy is potentially a new branch, the
293
command is called *branch*::
465
% bzr branch http://bazaar-vcs.org/bzr/bzr.dev
295
% bzr branch http://bazaar-ng.org/bzr/bzr.dev
468
This copies down the complete history of this branch, so we can do all
469
operations on it locally: log, annotate, making and merging branches.
470
There will be an option to get only part of the history if you wish.
298
This copies down the complete history of this branch, so we can
299
do all operations on it locally: log, annotate, making and merging
300
branches. There will be an option to get only part of the history if
472
305
Following upstream changes
473
306
==========================
475
You can stay up-to-date with the parent branch by "pulling" in their
308
You can stay up-to-date with the parent branch by *pulling*
480
After this change, the local directory will be a mirror of the source. This
481
includes the ''revision-history'' - which is a list of the commits done in
482
this branch, rather than merged from other branches.
484
This command only works if your local (destination) branch is either an
485
older copy of the parent branch with no new commits of its own, or if the
486
most recent commit in your local branch has been merged into the parent
489
Merging from related branches
490
=============================
492
If two branches have diverged (both have unique changes) then **bzr
493
merge** is the appropriate command to use. Merge will automatically
494
calculate the changes that exist in the branch you're merging from that
495
are not in your branch and attempt to apply them in your branch.
502
If there is a conflict during a merge, 3 files with the same basename are
503
created. The filename of the common base is appended with .BASE, the
504
filename of the file containing your changes is appended .THIS and the
505
filename with the changes from the other tree is appended .OTHER.
506
Using a program such as kdiff3, you can now comfortably merge them into
507
one file. To commit you have to rename it to the original basename and
508
delete the other two files. As long as there exist files with .BASE, .THIS
509
or .OTHER the commit command will complain.
511
[**TODO**: explain conflict markers within files]
514
Publishing your branch
515
======================
517
You don't need a special server to publish a bzr branch, just a normal web
518
server. Just mirror the files to your server, including the .bzr
519
directory. One can push a branch (or the changes for a branch) by one of
520
the following three methods:
522
* Rsync: rsync -avrz LOCALBRANCH servername.com/this/directory/here
524
(or any other tool for publishing a directory to a web site.)
526
* bzr push sftp://servername.com/this/directory/here
528
(The directory that must already exist)
530
* The rspush plugin that comes with BzrTools
533
Moving changes between trees
534
============================
536
It happens to the best of us: sometimes you'll make changes in the wrong
537
tree. Maybe because you've accidentally started work in the wrong directory,
538
maybe because as you're working, the change turns out to be bigger than you
539
expected, so you start a new branch for it.
541
To move your changes from one tree to another, use
546
% bzr merge --uncommitted OLDDIR
548
This will apply all of the uncommitted changes you made in OLDDIR to NEWDIR.
549
It will not apply committed changes, even if they could be applied to NEWDIR
550
with a regular merge. The changes will remain in OLDDIR, but you can use **bzr
551
revert OLDDIR** to remove them, once you're satisfied with NEWDIR.
553
NEWDIR does not have to be a copy of OLDDIR, but they should be related.
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The more different they are, the greater the chance of conflicts.
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This only works if the local branch if your branch includes only
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changes from the parent branch. Otherwise, the branches are said to
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have *diverged*, and they must be merged instead.
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tutorial.txt
