gitcvs-migration - Git for CVS users
git cvsimport *
Git differs from CVS in that every working tree contains a repository with a
full copy of the project history, and no repository is inherently more
important than any other. However, you can emulate the CVS model by
designating a single shared repository which people can synchronize with; this
document explains how to do that.
Some basic familiarity with Git is required. Having gone through
(7) and gitglossary
(7) should be sufficient.
Suppose a shared repository is set up in /pub/repo.git on the host foo.com. Then
as an individual committer you can clone the shared repository over ssh with:
$ git clone foo.com:/pub/repo.git/ my-project
$ cd my-project
and hack away. The equivalent of cvs update
which merges in any work that others might have done since the clone operation.
If there are uncommitted changes in your working tree, commit them first
before running git pull.
command knows where to get updates from because of certain
configuration variables that were set by the first git clone
see git config -l
and the git-config
(1) man page for details.
You can update the shared repository with your changes by first committing your
changes, and then using the git push
to "push" those commits to the shared repository. If someone else has
updated the repository more recently, git push
, like cvs commit
will complain, in which case you must pull any changes before attempting the
In the git push
command above we specify the name of the remote branch to
update ( master
). If we leave that out, git push
tries to update
any branches in the remote repository that have the same name as a branch in
the local repository. So the last push
can be done with either of:
$ git push origin
$ git push foo.com:/pub/project.git/
as long as the shared repository does not have any branches other than
We assume you have already created a Git repository for your project, possibly
created from scratch or from a tarball (see gittutorial
imported from an already existing CVS repository (see the next section).
Assume your existing repo is at /home/alice/myproject. Create a new
"bare" repository (a repository without a working tree) and fetch
your project into it:
$ mkdir /pub/my-repo.git
$ cd /pub/my-repo.git
$ git --bare init --shared
$ git --bare fetch /home/alice/myproject master:master
Next, give every team member read/write access to this repository. One easy way
to do this is to give all the team members ssh access to the machine where the
repository is hosted. If you don’t want to give them a full shell on
the machine, there is a restricted shell which only allows users to do Git
pushes and pulls; see git-shell
Put all the committers in the same group, and make the repository writable by
$ chgrp -R $group /pub/my-repo.git
Make sure committers have a umask of at most 027, so that the directories they
create are writable and searchable by other group members.
These instructions use the git-cvsimport
script which ships with git, but
other importers may provide better results. See the note in
(1) for other options.
First, install version 2.1 or higher of cvsps from
and make sure it is in your path.
Then cd to a checked out CVS working directory of the project you are
interested in and run git-cvsimport
$ git cvsimport -C <destination> <module>
This puts a Git archive of the named CVS module in the directory
<destination>, which will be created if necessary.
The import checks out from CVS every revision of every file. Reportedly
cvsimport can average some twenty revisions per second, so for a medium-sized
project this should not take more than a couple of minutes. Larger projects or
remote repositories may take longer.
The main trunk is stored in the Git branch named origin
, and additional
CVS branches are stored in Git branches with the same names. The most recent
version of the main trunk is also left checked out on the master
branch, so you can start adding your own changes right away.
The import is incremental, so if you call it again next month it will fetch any
CVS updates that have been made in the meantime. For this to work, you must
not modify the imported branches; instead, create new branches for your own
changes, and merge in the imported branches as necessary.
If you want a shared repository, you will need to make a bare clone of the
imported directory, as described above. Then treat the imported directory as
another development clone for purposes of merging incremental imports.
Git allows you to specify scripts called "hooks" to be run at certain
points. You can use these, for example, to send all commits to the shared
repository to a mailing list. See githooks
You can enforce finer grained permissions using update hooks. See Controlling
access to branches using update hooks
It is also possible to provide true CVS access to a Git repository, so that
developers can still use CVS; see git-cvsserver
(1) for details.
CVS users are accustomed to giving a group of developers commit access to a
common repository. As we’ve seen, this is also possible with Git.
However, the distributed nature of Git allows other development models, and
you may want to first consider whether one of them might be a better fit for
For example, you can choose a single person to maintain the project’s
primary public repository. Other developers then clone this repository and
each work in their own clone. When they have a series of changes that
they’re happy with, they ask the maintainer to pull from the branch
containing the changes. The maintainer reviews their changes and pulls them
into the primary repository, which other developers pull from as necessary to
stay coordinated. The Linux kernel and other projects use variants of this
With a small group, developers may just pull changes from each other’s
repositories without the need for a central maintainer.
(7), The Git User’s
Part of the git
- Controlling access to branches using update hooks
- The Git User’s Manual