| gitcvs-migration(7) |
| =================== |
| |
| NAME |
| ---- |
| gitcvs-migration - Git for CVS users |
| |
| SYNOPSIS |
| -------- |
| [verse] |
| '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 |
| linkgit:gittutorial[7] and |
| linkgit: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 linkgit: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 |
| linkgit: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 linkgit: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 |
| link:http://www.cobite.com/cvsps/[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 linkgit: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 linkgit:githooks[5]. |
| |
| You can enforce finer grained permissions using update hooks. See |
| link:howto/update-hook-example.txt[Controlling access to branches using |
| update hooks]. |
| |
| 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 linkgit: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 |
| -------- |
| linkgit:gittutorial[7], |
| linkgit:gittutorial-2[7], |
| linkgit:gitcore-tutorial[7], |
| linkgit:gitglossary[7], |
| link:everyday.html[Everyday Git], |
| link:user-manual.html[The Git User's Manual] |
| |
| GIT |
| --- |
| Part of the linkgit:git[1] suite. |