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.

SETTING UP A SHARED REPOSITORY

   We assume you have already created a Git repository for your project,
   possibly created from scratch or from a tarball (see gittutorial(7)),
   or 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(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

       Note
       These instructions use the git-cvsimport script which ships with
       git, but other importers may provide better results. See the note
       in git-cvsimport(1) for other options.

   First, install version 2.1 or higher of cvsps from
   https://github.com/andreyvit/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, 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 your project.

   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 model.

   With a small group, developers may just pull changes from each other's
   repositories without the need for a central maintainer.

SEE ALSO

   gittutorial(7), gittutorial-2(7), gitcore-tutorial(7), gitglossary(7),
   giteveryday(7), The Git User's Manual[2]

GIT

   Part of the git(1) suite.

NOTES

    1. Controlling access to branches using update hooks
       file:///usr/share/doc/git/html/howto/update-hook-example.html

    2. The Git User's Manual
       file:///usr/share/doc/git/html/user-manual.html

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