GITCVS-MIGRATION(7) Git Manual GITCVS-MIGRATION(7)
NAME
gitcvs-migration - Git for CVS users
SYNOPSIS
git cvsimport *
DESCRIPTION
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 gittutorial(7) and gitglossary(7) should be
sufficient.
DEVELOPING AGAINST A SHARED REPOSITORY
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 is
$ git pull origin
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.
Note
The pull command knows where to get updates from because of certain configuration variables that were set
by the first git clone command; 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 command:
$ git push origin master
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 push
again.
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 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(1).
Put all the committers in the same group, and make the repository writable by that group:
$ 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.
IMPORTING A CVS ARCHIVE
First, install version 2.1 or higher of cvsps from http://www.cobite.com/cvsps/ 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(1):
$ 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.
ADVANCED SHARED REPOSITORY MANAGEMENT
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(5).
You can enforce finer grained permissions using update hooks. See Controlling access to branches using update
hooks[1].
PROVIDING CVS ACCESS TO A GIT REPOSITORY
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.
ALTERNATIVE DEVELOPMENT MODELS
CVS users are accustomed to giving a group of developers commit access to a common repository. As we’ve seen,
SEE ALSO
gittutorial(7), gittutorial-2(7), gitcore-tutorial(7), gitglossary(7), Everyday Git[2], The Git User’s
Manual[3]
GIT
Part of the git(1) suite.
NOTES
1. Controlling access to branches using update hooks
file:///usr/share/doc/git-1.8.3.1/howto/update-hook-example.txt
2. Everyday Git
file:///usr/share/doc/git-1.8.3.1/everyday.html
3. The Git User’s Manual
file:///usr/share/doc/git-1.8.3.1/user-manual.html
Git 1.8.3.1 03/23/2016 GITCVS-MIGRATION(7)
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