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1gitcvs-migration(7)
2===================
3
4NAME
5----
2de9b711 6gitcvs-migration - Git for CVS users
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7
8SYNOPSIS
9--------
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10[verse]
11'git cvsimport' *
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12
13DESCRIPTION
14-----------
fcbfd5a6 15
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16Git differs from CVS in that every working tree contains a repository with
17a full copy of the project history, and no repository is inherently more
18important than any other. However, you can emulate the CVS model by
19designating a single shared repository which people can synchronize with;
20this document explains how to do that.
fcbfd5a6 21
2de9b711 22Some basic familiarity with Git is required. Having gone through
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23linkgit:gittutorial[7] and
24linkgit:gitglossary[7] should be sufficient.
fcbfd5a6 25
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26Developing against a shared repository
27--------------------------------------
fcbfd5a6 28
cd976f5c 29Suppose a shared repository is set up in /pub/repo.git on the host
37425065 30foo.com. Then as an individual committer you can clone the shared
cd976f5c 31repository over ssh with:
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32
33------------------------------------------------
34$ git clone foo.com:/pub/repo.git/ my-project
35$ cd my-project
36------------------------------------------------
37
2fd02c92 38and hack away. The equivalent of 'cvs update' is
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39
40------------------------------------------------
41$ git pull origin
42------------------------------------------------
43
44which merges in any work that others might have done since the clone
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45operation. If there are uncommitted changes in your working tree, commit
46them first before running git pull.
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47
48[NOTE]
49================================
5833d730 50The 'pull' command knows where to get updates from because of certain
0b444cdb 51configuration variables that were set by the first 'git clone'
5162e697 52command; see `git config -l` and the linkgit:git-config[1] man
c04197ee 53page for details.
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54================================
55
4cfeccc7 56You can update the shared repository with your changes by first committing
0b444cdb 57your changes, and then using the 'git push' command:
fcbfd5a6 58
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59------------------------------------------------
60$ git push origin master
61------------------------------------------------
fcbfd5a6 62
4003a58e 63to "push" those commits to the shared repository. If someone else has
0b444cdb 64updated the repository more recently, 'git push', like 'cvs commit', will
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65complain, in which case you must pull any changes before attempting the
66push again.
7da71deb 67
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68In the 'git push' command above we specify the name of the remote branch
69to update (`master`). If we leave that out, 'git push' tries to update
b8bc67ce 70any branches in the remote repository that have the same name as a branch
5833d730 71in the local repository. So the last 'push' can be done with either of:
7da71deb 72
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73------------
74$ git push origin
cd976f5c 75$ git push foo.com:/pub/project.git/
b8bc67ce 76------------
7da71deb 77
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78as long as the shared repository does not have any branches
79other than `master`.
80
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81Setting Up a Shared Repository
82------------------------------
83
2de9b711 84We assume you have already created a Git repository for your project,
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85possibly created from scratch or from a tarball (see
86linkgit:gittutorial[7]), or imported from an already existing CVS
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87repository (see the next section).
88
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89Assume your existing repo is at /home/alice/myproject. Create a new "bare"
90repository (a repository without a working tree) and fetch your project into
91it:
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92
93------------------------------------------------
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94$ mkdir /pub/my-repo.git
95$ cd /pub/my-repo.git
5c94f87e 96$ git --bare init --shared
4cfeccc7 97$ git --bare fetch /home/alice/myproject master:master
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98------------------------------------------------
99
100Next, give every team member read/write access to this repository. One
101easy way to do this is to give all the team members ssh access to the
102machine where the repository is hosted. If you don't want to give them a
103full shell on the machine, there is a restricted shell which only allows
2de9b711 104users to do Git pushes and pulls; see linkgit:git-shell[1].
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105
106Put all the committers in the same group, and make the repository
107writable by that group:
108
109------------------------------------------------
4cfeccc7 110$ chgrp -R $group /pub/my-repo.git
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111------------------------------------------------
112
113Make sure committers have a umask of at most 027, so that the directories
114they create are writable and searchable by other group members.
115
116Importing a CVS archive
117-----------------------
118
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119NOTE: These instructions use the `git-cvsimport` script which ships with
120git, but other importers may provide better results. See the note in
121linkgit:git-cvsimport[1] for other options.
122
cd976f5c 123First, install version 2.1 or higher of cvsps from
72e0877a 124https://github.com/andreyvit/cvsps[https://github.com/andreyvit/cvsps] and make
4cfeccc7 125sure it is in your path. Then cd to a checked out CVS working directory
3ac3cfb8 126of the project you are interested in and run linkgit:git-cvsimport[1]:
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127
128-------------------------------------------
0bc25a78 129$ git cvsimport -C <destination> <module>
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130-------------------------------------------
131
2de9b711 132This puts a Git archive of the named CVS module in the directory
4cfeccc7 133<destination>, which will be created if necessary.
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134
135The import checks out from CVS every revision of every file. Reportedly
136cvsimport can average some twenty revisions per second, so for a
137medium-sized project this should not take more than a couple of minutes.
138Larger projects or remote repositories may take longer.
139
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140The main trunk is stored in the Git branch named `origin`, and additional
141CVS branches are stored in Git branches with the same names. The most
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142recent version of the main trunk is also left checked out on the `master`
143branch, so you can start adding your own changes right away.
144
145The import is incremental, so if you call it again next month it will
146fetch any CVS updates that have been made in the meantime. For this to
147work, you must not modify the imported branches; instead, create new
148branches for your own changes, and merge in the imported branches as
149necessary.
b8bc67ce 150
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151If you want a shared repository, you will need to make a bare clone
152of the imported directory, as described above. Then treat the imported
153directory as another development clone for purposes of merging
154incremental imports.
155
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156Advanced Shared Repository Management
157-------------------------------------
158
159Git allows you to specify scripts called "hooks" to be run at certain
160points. You can use these, for example, to send all commits to the shared
6998e4db 161repository to a mailing list. See linkgit:githooks[5].
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162
163You can enforce finer grained permissions using update hooks. See
d5ff3b4b 164link:howto/update-hook-example.html[Controlling access to branches using
b8bc67ce 165update hooks].
fcbfd5a6 166
2de9b711 167Providing CVS Access to a Git Repository
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168----------------------------------------
169
2de9b711 170It is also possible to provide true CVS access to a Git repository, so
5162e697 171that developers can still use CVS; see linkgit:git-cvsserver[1] for
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172details.
173
174Alternative Development Models
175------------------------------
176
177CVS users are accustomed to giving a group of developers commit access to
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178a common repository. As we've seen, this is also possible with Git.
179However, the distributed nature of Git allows other development models,
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180and you may want to first consider whether one of them might be a better
181fit for your project.
182
183For example, you can choose a single person to maintain the project's
184primary public repository. Other developers then clone this repository
185and each work in their own clone. When they have a series of changes that
186they're happy with, they ask the maintainer to pull from the branch
187containing the changes. The maintainer reviews their changes and pulls
188them into the primary repository, which other developers pull from as
189necessary to stay coordinated. The Linux kernel and other projects use
190variants of this model.
b0bf8f24 191
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192With a small group, developers may just pull changes from each other's
193repositories without the need for a central maintainer.
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194
195SEE ALSO
196--------
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197linkgit:gittutorial[7],
198linkgit:gittutorial-2[7],
199linkgit:gitcore-tutorial[7],
200linkgit:gitglossary[7],
673151a9 201linkgit:giteveryday[7],
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202link:user-manual.html[The Git User's Manual]
203
204GIT
205---
941b9c52 206Part of the linkgit:git[1] suite