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Using CVS

This appendix provides instructions on performing a few essential version control operations using the CVS client tool. It doesn’t offer detailed guidance on using CVS. Consult the CVS documentation for in-depth explanations.

In this section:

The cvs and ocvs Tools
Creating a CVS Repository
Accessing a CVS Repository
Importing Projects Into a CVS Repository
Checking Out Projects From a CVS Repository
Updating a Local Project File to the Latest Version in a CVS Repository

The cvs and ocvs Tools

CVS is installed in Mac OS X. Max OS X version 10.4 includes two versions of CVS: the legacy version (version 1.10), which supports wrappers and the current version (version 1.11.18), which doesn’t support wrappers. CVS with wrapper support is required when you work on projects that contain bundles, such as nibs, which are directories that group a set of files as a discrete package (see Bundle Programming Guide for details). When you use CVS with wrappers, bundles are compressed into a single file before they are placed in the repository and decompressed when they are checked out to local copies.

In Mac OS X v10.4, the CVS tool that supports wrappers is /usr/bin/ocvs, (this is the same version of the tool that shipped on earlier versions of Mac OS X). The current version of the CVS tool is /usr/bin/cvs. It incorporates fixes to security problems in earlier versions of CVS. Xcode is initially configured to use ocvs.

You must use the ocvs tool when working on projects hosted on repositories created using CVS 1.10 or earlier. Also, you must host new projects containing bundles in repositories created using CVS 1.10 or earlier. You should host new projects that don’t use bundles in repositories created using CVS version 1.11.18 or later.

Creating a CVS Repository

Most developers don’t need to worry about creating or managing repositories. This task is usually handled by system administrators. However, if you’re a member of a very small team or the sole programmer in your organization, you may have to create and maintain the repository that holds your company’s source code. Or you may create a local repository to experiment with version control in your computer.

To create a CVS repository, create the CVS root directory (the directory that contains the repository) and initialize the repository. If you want others to access the repository, you should create a group containing their user names and assign the group to the root directory.

Creating the cvsusers Group

To create the CVS users group, execute these commands in Terminal:

% sudo nicl . -create /groups/cvsusers // 1

% sudo nicl . -append /groups/cvsusers gid 600 // 2

% sudo nicl . -append /groups/cvsusers users <user1> <user2>  ... <userN> // 3

% lookupd -flushcache // 4

% memberd -r // 5

This is what the commands do:

1. Creates the cvsusers group.

2. Assigns an ID number to the cvsusers group. You can use any unused group ID number.

3. Assigns a list of user names to the cvsusers group.

4. Flushes the directory information cache.

5. Resolves the memberships of the new group.

Creating the Root Directory

To create the repository’s root directory, execute the following commands:

% sudo mkdir /cvsrep // 1

% sudo chgrp cvsusers /cvsrep // 2

% sudo chmod g+w /cvsrep // 3

This is what the commands do:

1. Creates the /cvsrep directory.

2. Assigns the cvsusers group to the directory.

3. Gives write permission to the cvsusers group for the directory.

Initializing the Repository

To initialize the repository, execute the following commands:

% setenv CVSROOT /cvsrep         # 'export CVSROOT=/cvsrep' in bash

% sudo cvs init

Accessing a CVS Repository

You can access local repositories (that is, repositories that reside on the same computer on which you develop) directly. For repositories located in remote computers, however, CVS uses secure connection methods, such as SSH. See the CVS documentation for information on other secure connection methods.

This section shows how to configure environment variables to enable SSH-based access to a CVS repository. For information on how to set up the required private and public keys, see “Configuring Your SSH Environment.”

To access a CVS repository through SSH, you need to configure the CVSROOT and CVS_RSH environment variables for your user account:

1. Set CVSROOT so that it defines the user under which to log in, the computer the repository resides in, and the path to the repository's root directory, using the following format:

   :ext:<user>@<host><repository_path>

   For example:

   setenv CVSROOT :ext:ming@server.apple.com:/cvsrep

2. Set CVS_RSH to ssh:

   setenv CVS_RSH ssh

For more information on using SSH to access a remote CVS repository, consult the CVS documentation.

Importing Projects Into a CVS Repository

To add a project directory to a CVS repository, use the cvs import command, which operates on the current working directory. You must have the CVSROOT environment variable set to the CVS root directory (see “Creating a CVS Repository”). The command’s syntax is:

cvs import -m "<import_comment>" <module_name>  <tag> start

For example, to import the project directory /Developer/Examples/Networking/Echo, you issue the following commands in Terminal:

% cd /Developer/Examples/Networking/Echo

% cvs import -m "Echo added to repository" Echo Echo_1  start

Before adding a project directory to a repository, you should move or delete the build directory if it resides in the project directory. You should also move or delete any other directories you don’t want to add to the repository. Otherwise, changes to files in those directories are tracked by your version control system and added to the repository.

Checking Out Projects From a CVS Repository

To check out a project in a CVS repository, use the cvs checkout command. The command's syntax is:

cvs checkout <module_name>

For example:

% cd ~/src

% cvs checkout Echo

Updating a Local Project File to the Latest Version in a CVS Repository

When Xcode is unable to open a project because its project file (project.pbxproj) is corrupted, you must use the cvs update command to get the latest version from the repository. For example, to update the project package in a project named Grape using cvs, you execute the cvs update command on the project file, as shown here:

% cvs update -C Grape.xcode/project.pbxproj

(Locally modified project.pbxproj moved to .#project.pbxproj.1.4)

U Grape.xcode/project.pbxproj

To do the same using ocvs, execute the following commands:

% mv Grape.xcode/project.pbxproj /tmp

% ocvs update Grape.xcode/project.pbxproj

ocvs update: warning: Grape.xcode/project.pbxproj was lost

U Grape.xcode/project.pbxproj

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