cvs2svn/cvs2bzr is a tool that can be used to migrate CVS
repositories to newer version control tools, including Bazaar. Bazaar is an adaptive
version control system that supports both centralised and distributed
version control. It is most famous for being used for Ubuntu and
MySQL development. The program used to convert to Bazaar, called
cvs2bzr, is distributed as part of the cvs2svn project.
If you are reading this documentation on the cvs2svn website, then please be
aware that it describes the current trunk version of cvs2svn, which
may be different than the most recent released version. Please refer
to the documentation that was included with your version of cvs2svn.
Conversion to Bazaar was added in release 2.3 of cvs2svn and may have
improved significantly since then. Please make sure you are using an
up-to-date version of cvs2svn--perhaps even the development trunk
cvs2bzr requires the following:
- Direct (filesystem) access to a copy of the CVS repository that
you want to convert. cvs2bzr parses the files in the CVS
repository directly, so it is not enough to have remote CVS
access. See the FAQ for more
information and a possible workaround.
- Python 2, version 2.4 or later. See http://www.python.org/.
(cvs2bzr does not work with Python 3.x.)
- If you use the --use-rcs option, then RCS's `co'
program is required. The RCS home page is
See the --use-rcs flag for more
- If you use the --use-cvs option, then the `cvs' command
is required. The CVS home page is
See the --use-cvs flag for more
- Bazaar version 1.13 or later.
- The bzr-fastimport plugin version 0.9 or later.
Most of the work of converting a repository from CVS to a more
modern version control system is inferring the most likely history
given the incomplete information that CVS records. cvs2svn has a long
history of making sense of even the most convoluted CVS repositories,
and cvs2bzr uses this same machinery. Therefore, cvs2bzr inherits the
robustness and many of the features of
cvs2svn. cvs2svn can convert just about every CVS repository we
have ever seen, and includes a plethora of options for customizing
The output of cvs2bzr is a "fastimport" dump file that can be
imported into Bazaar using the bzr-fastimport
Although cvs2bzr is considerably newer than cvs2svn, and much less
well tested, it is believed that cvs2bzr can (cautiously) be used for
production conversions. If you use cvs2bzr, please let us know how it
worked for you!
cvs2bzr still has many limitations compared to cvs2svn. The main
cvs2svn developer has limited Bazaar experience and very limited time, so
help would be much appreciated! Some of these missing
features would be pretty easy to program, and I'd be happy to help you
- The cvs2bzr documentation is still rather thin. See below for more references.
- CVS allows a branch to be created from arbitrary combinations of
source revisions and/or source branches. cvs2bzr tries to create
a branch from a single source, but if it can't figure out how to,
it creates the branch using "merge" from multiple sources. In
pathological situations, the number of merge sources for a branch
can be arbitrarily large.
- There are no checks that CVS branch and tag names are legal
names in Bazaar. This is unlikely to be a problem because Bazaar
uses paths for branch names similar to CVS and Subversion. Tag
naming in Bazaar is also more flexible than in git, say.
- Only single projects can be converted at a time. Given the way
Bazaar is typically used, I don't think that this is a significant
- cvs2bzr is not especially fast. Among other things, it still
uses RCS or CVS to extract the contents of the CVS revisions.
Implementing the --internal-co option for cvs2bzr (using
code that already exists in cvs2svn) might improve the conversion
- The cvs2svn test suite does not include meaningful tests of
- cvs2bzr makes no attempt to convert .cvsignore files
into .bzrignore files.
- cvs2bzr, like cvs2svn, does not support incremental conversion
(i.e., tracking a live CVS repository). However, this possible
workaround for using cvs2git along those lines might provide
some assistance for anyone wanting to try doing that using
There is some documentation specific to cvs2bzr, and much of the
cvs2svn documentation also applies fairly straightforwardly to
cvs2bzr. See the following sources:
- This document.
- The cvs2bzr man page and the output of cvs2bzr
- The cvs2svn documentation and
the cvs2svn FAQ, which contain much general
discussion and describe many features that can also be used for
- cvs2bzr-example.options in the cvs2svn source tree,
which is an example of an options file that can be used to
configure a cvs2bzr conversion. The file is extensively
- The cvs2svn mailing lists, IRC channel, etc., as described in the cvs2svn FAQ.
Bazaar Data Migration Guide.
This section outlines the steps needed to convert a CVS repository
to Bazaar using cvs2bzr.
- Be sure that you have the requirements,
including either RCS or CVS (used to read revision contents from
the CVS repository).
- Obtain a copy of cvs2svn/cvs2bzr version 2.3 or newer. It is
recommended that you use the most recent version available, or
even the development version.
- To install cvs2svn from a tarball,
simply unpack the tarball into a directory on your conversion
computer (cvs2bzr can be run directly from this
To check out the current trunk version of cvs2svn, make
sure that you have Subversion installed and then run:
svn co --username=guest --password="" http://cvs2svn.tigris.org/svn/cvs2svn/trunk cvs2svn-trunk
make man # If you want to create manpages for the main programs
make check # ...optional
Please note that the test suite includes tests that are
marked "XFAIL" (expected failure); these are known and are
not considered serious problems.
Configure cvs2bzr for your conversion. This can be done via
command-line options or via an options file:
- The command-line options for running cvs2bzr are documented
in the cvs2bzr man page and in the output of cvs2bzr
The more flexible options-file method
requires you to create an options file, then start cvs2bzr
Use cvs2bzr-example.options in the cvs2svn source
tree as your starting point; the file contains lots of
Run cvs2bzr. This creates an output file in fast-import
format. The name of this file is specified by
your options file or a command-line argument. In the example,
the file is named cvs2svn-tmp/dumpfile.fi.
Load the dump file using bzr fast-import:
bzr fast-import cvs2svn-tmp/dumpfile.fi project.bzr
Feedback would be much appreciated, including reports of success
using cvs2bzr. Please send comments, bug reports, and patches to