Subversion and XCode
Volume Number: 22 (2006)
Issue Number: 11
Column Tag: Subversion and XCode
Subversion and XCode
Source control management on XCode using Subversion.
by Jose R.C. Cruz
Introduction
Since its release, the MacOS X platform uses CVS as its default source control management (SCM) system. This tool is used for tracking changes made to a project as well as for coordinating efforts and contributions from other users. It is not, however, without its shortcomings. Its inability to handle non-ASCII files and lack of support for binary formats has been a source of frustration for many users. Furthermore, some actions such as reversions and conflict resolutions are less than adequately implemented in CVS.
To address these limitations, the open-source community developed Subversion. This article will serve as a concise introduction to the new tool. It will detail how the tool improves upon CVS as well as provide an overview of its repository structure. It will demonstrate how to use the tool to perform basic SCM operations using the tool as well as how it integrates with the XCode development environment.
Readers are expected to have a working knowledge of XCode as well as the Terminal application. Also, most examples will use bash as the default shell and the CurrencyConverter tutorial as the default project.
The Subversion Tool
The Subversion project
The Subversion (svn) project is an open-source project focused on developing a viable replacement for the CVS tool. It shares the same key developers as CVS, and has its official source repository maintained by CollabNet, Inc.
At the time of this writing, sources for the latest development version (1.3.2) are available as a downloadable tarball file at <subversion.tigris.org>. The latest stable version of the tool (1.3.1) is also available at the same site. The site also provides links to binary installers for various platforms, including OS X. Both binaries and sources are distributed to the public under an Apache/BSD compatible license.
The Subversion Advantage
Subversion provides numerous advantages over CVS. The most notable one is that all project files, regardless of format, are now stored into the repository as binary files. Also, project subdirectories are treated as valid repository items. They can be added, copied, deleted, and renamed like any other project file.
Subversion uses a space-efficient binary diff algorithm to store its repository items. This allows the repository to support multimedia files without causing it to grow to an unwieldy size. Also, all committal transactions are now handled atomically. This ensures that each transaction is allowed to complete without interruption, and protects the repository from corruption caused by simultaneous write accesses.
Finally, Subversion provides a much better complement of subcommands for invoking various SCM transactions. Some subcommands such as add, commit, and export behave similarly to their CVS counterparts. Others such as status, move, and revert are used to perform the same operations that would otherwise require multiple steps or command options on CVS.
Installing Subversion on OS X
The only notable disadvantage of Subversion is that it is not bundled with any versions of MacOS X. This is easily resolved, however, by first downloading the disk image file for version 1.3.1 at <http://metissian.com/projects/macosx/subversion>. Make sure to download only the client version of the tool
Double-click on the .dmg file to mount the image on the Finder. Locate the SubversionClient-1.30.pkg package and double-click on it to start the installation process. Follow the ensuing instructions to complete installation.
The installer package will place the Subversion tools and support files in the /usr/local directory. In order to use the tools, the PATH environment needs to be updated in order for the shell to know their locations. Use your favorite text editor to add the following lines to the hidden .bash_profile file on your home directory.
PATH=usr/local/man:/usr/local/share:$PATH
export PATH=/usr/local/bin:/usr/local/lib:$PATH
To test to see if Subversion is correctly installed, type svn --help at the Terminal prompt. Subversion should display its version and a list of all available subcommands.
The Subversion Repository
Creating the repository
Like CVS, you will have to create an empty repository wherein which to store your project archive. First add the following line to the .bash_profile file using your favorite text editor.
export SVNROOT=path_to_your_repository
Then type svnadmin create $SVNROOT at the Terminal prompt to create the repository.
For example, to create Subversion repository to be located at /Users/Shared/SVN, the entry for the .bash_profile file should read as
export SVNROOT=/Users/Shared/SVN
Then, by typing svnadmin $SVNROOT creates an empty repository at the specified location. If the SVN subdirectory does not exist, the svnadmin tool creates one at the specified path. However, if the enclosing directory /Users/Shared does not exists as well, the tool will instead generate an error.
Unlike CVS, Subversion does not maintain a default repository path. In fact, it allows you to access multiple repositories at a time. The SVNROOT shell variable introduced here helps reduce the amount of typing necessary to invoke a Subversion subcommand.
Figure 1 shows the directory structure of the newly created repository. It consists of a number of configuration files and scripts, as well as eight subdirectories. The only one of interest in this article is the db subdirectory. For a detailed description of the other repository items, read Chapter 5 of the Subversion user manual.
The db subdirectory is where Subversion maintains your project archives. It contains three subdirectories as well as additional support files. Each project archive revision is stored in the revs subdirectory. Properties for each archive are stored in the revprops subdirectory. The transactions subdirectory is used to contain files required by an SCM transaction. Those same files are then removed when that transaction completes itself.
By default, Subversion uses Berkeley DB as the format for its repository database. Interestingly enough, the MacOS X version uses FSFS, also known as The [Versioned] Filesystem, as its database format. This format has the advantage of being platform agnostic and multi-user friendly. It also provides better I/O performance by taking advantage of the underlying native filesystem. Furthermore, it allows the repository to be accessible over a network connection.
For more information on the two repository formats, read Chapter 5 of the user manual.
Figure 1. The SVN Repository.
Adding a project
Before adding a project to the repository, make sure to arrange its directory contents as shown in Figure 2. The trunk subdirectory will contain those files representing the main development line of the project. This is where you will have your images, plists, nibs, source, and header files, as well as the subdirectories used to organize those files. The branches subdirectory is where Subversion stores the branches created for each file. Branches that were unaltered and destroyed are stored in the tags subdirectory.
Figure 2. The recommended SVN project layout.
This directory structure is recommended only if you are maintaining a central repository to store your project archives. If you are maintaining separate repositories for each project, then you may choose not to adopt this structure.
To add a project to the repository, type
svn import project_directory_name file://$SVNROOT/project_name \
-m "project_import_message"
at the Terminal prompt. Notice that the repository path is first preceded by the URL token file://. This indicates the repository is located in the same physical machine as the project. If the repository were located over a network, its path would then be preceded by either an http:// or svn:// token. For more information on how to setup a network repository, consult Chapter 6 of the user manual.
For example, to add the CurrencyConverter project to the repository, first navigate to the directory containing the project using the Terminal application. Then type
svn import CurrencyConverter file://$SVNROOT/CurrencyConverter \
-m "Adding the Currency Converter tutorial demo"
at the prompt. To check if the project was successfully added to the repository, type
svnlook tree $SVNROOT
at the prompt. Subversion responds by displaying the tree structure of each archived projects (Listing 1), one of which belongs to CurrencyConverter.
Listing 1. Sample Subversion tree structure.
/
CurrencyConverter/
trunk/
main.m
ConverterController.h
Converter.m
currCnvrt.pbproj/
aUser.pbxuser
project.pbxproj
ConverterController.m
Converter.h
English.lproj/
InfoPlist.strings
MainMenu.nib/
objects.nib
info.nib
keyedobjects.nib
classes.nib
MainMenu~.nib/
objects.nib
info.nib
keyedobjects.nib
classes.nib
branches/
tags/
Now to remove a project from the repository, type
svn delete file://$SVNROOT/project_name -m "reasons_for_removal"
at the Terminal prompt. Subversion will then quietly delete all references to the project from its repository. Also, typing svnlook tree $SVNROOT will show that the project is no longer "available". Since deletion also invokes an immediate committal, make sure to provide an appropriate message for the revision log. Otherwise, Subversion will not process the deletion request.
Unlike in CVS, the svn delete subcommand only removes the latest or head revision of the project. Previous revisions of the project are still present in the repository and are accessible for checkouts. The only way to completely remove the project is to create a replacement repository and restore it from the last backup file created before that project was added.
Backing up the repository
One Subversion feature that was not mentioned earlier is its ability to create repository backups. Equally important, it can create these backups without having to take the entire repository offline.
One way to backup the repository is to type
svnadmin hotcopy $SVNROOT backup_directory_path
at the Terminal prompt. Subversion will copy the entire repository located at SVNROOT and place it at the specified directory. For example, typing svnadmin hotcopy $SVNROOT /Users/Public/Backup creates the backup copy at /Users/Public/Backup. Make sure the backup directory exists; otherwise, Subversion will generate an error.
Another way to backup the repository is to type
svnadmin dump $SVNROOT > backup_file
at the Terminal prompt. Here, Subversion stores the entire contents of its repository into backup_file. The format used by the file is portable and platform agnostic, making it a suitable way of moving the repository from one filesystem to another. You can also create incremental backups by typing
svnadmin dump $SVNROOT --incremental > backup_file
at the prompt. The option --incremental tells Subversion to retrieve only those changes added to the repository since the last complete svnadmin dump. The resulting backup file will be smaller as a result.
Restoring from a backup is equally straightforward. If svnadmin hotcopy is used to create the backup, the same subcommand can be used to do the restore by switching the positions of SVNROOT and the backup directory path as follows
svnadmin hotcopy backup_directory_path $SVNROOT
Make sure to take the old repository offline and delete it before replacing it with the backup copy.
If you used svnadmin dump to backup the repository, type
svnadmin load $SVNROOT < backup_file
at the Terminal prompt to restore the repository from backup_file. If incremental backups were made, make sure to restore each backup file in the same order that they were created. For example, if you backed up your repository as follows:
svnadmin dump $SVNROOT > 20060601.bak
svnadmin dump $SVNROOT --incremental > 20060610.bak
svnadmin dump $SVNROOT --incremental > 20060620.bak
you should restore your repository in the following sequence to avoid data corruption.
svnadmin load $SVNROOT < 20060601.bak
svnadmin load $SVNROOT < 20060610.bak
svnadmin load $SVNROOT < 20060620.bak
The Subversion Work Cycle
Figure 3 illustrates a basic Subversion work cycle. Subcommands that are marked in red represent those SCM transactions supported by the XCode environment. The rest should be invoked within the project directory through a Terminal session. They could also be invoked through the XCode Script menu. More on Subversion menu scripts will be discussed later on.
Figure 3. The Subversion work cycle.
Checking out a project
Like CVS, you first have to check out a copy of a project from the repository in order to work on it. To check out a working copy, type
svn checkout file://$SVNROOT/project_name destination_directory
at the Terminal prompt. Subversion will list each project file and subdirectory that was checked out, and places them at the specified directory. For example, typing
svn checkout file://$SVNROOT/CurrencyConverter ~/CurrencyConverter
places the CurrencyConverter project in the home directory.
Interestingly enough, Subversion does not provide the equivalent of a cvs release subcommand. Once you are done with your working copy, the only viable way of releasing it, is to manually delete your copy.
Updating the project
Like CVS, Subversion allows a team of users to work on the same project. If you are part of a team, you should always update your copy of the project on a regular basis. This allows you to catch and resolve any potential conflicts between your changes and theirs.
To update your working copy to the latest revision of the project, type svn update at the Terminal prompt. To update it to a specific revision, type svn update -r revision_number at the prompt.
For example, if John Doe has submitted his revision of the source file, Converter.m, first use the Terminal prompt to navigate to your copy of CurrencyConverter. Then type svn update at the prompt to update your copy of Converter.m to the new revision.
Consequently, if you want to find out which project files have been recently changed, type svn status project_name at the Terminal prompt. Subversion then generates a list of files and subdirectories with their current repository state. To display additional status information, type svn status -v project_name at the prompt.
If Subversion detects any conflicts between your working copy and the project archive, it generates three different files containing the conflicting changes. The .mine file contains those changes you have made on your working copy. The .rold_revision is the revision of that file from the archive before you made your changes. The .rnew_revision is the revision of same file from the archive while you were making your changes. Like in CVS, you manually examine each file and attempt to resolve the conflict manually. After you have resolved the conflict, type svn resolved project_file_name at the Terminal prompt to clear the conflict flag. Otherwise, Subversion will not allow you to commit your changes back into the repository.
For example, if your copy of Converter.m file, checked out at revision 3, conflicts with the latest revision (4) in the archive, Subversion generates the following three files:
Converter.mine Converter.r3 Converter.r4
Use your favorite text editor to manually examine and merge the conflicting changes. Once done, type svn resolved Converter.m at the prompt to clear the conflict flag.
Manipulating project items
Subversion allows you to easily add a new project item, like a file or subdirectory, to the repository archive. Furthermore, if the item happens to be a subdirectory containing additional items, Subversion will also add those items as well.
To add a new item to the repository, type svn add project_item_name at the Terminal prompt. For example, if a CurrencyConverter.icns file has been added to the CurrencyConverter project, type svn add CurrencyConverter.icns to add that file to the repository archive. Also, if the project bundle, CurrrencyConverter.proj, was converted to the new XCode 2.2 format, thus changing its extension to .xcodeproj, type svn add CurrencyConverter.xcodeproj at the prompt. Since a bundle is essentially a specialized subdirectory, Subversion will add the subdirectory, including the three files it contains, to the archive.
Subversion also makes it easier to copy, move, and delete existing project items, and then submit those changes back to the repository archive. To create a copy of an existing file or subdirectory, type svn copy project_item_name new_name at the Terminal prompt. To move (or rename) the file or subdirectory, type svn move project_item_name new_name at the prompt. To delete it, type svn delete project_item_name.
Subversion handles all four requests by first queuing them into its transaction queue. Then, on the next committal transaction, it executes each request in the order they were submitted. In the case of a copy, move or delete transaction, Subversion will perform the operation on the working copy of the project as well.
Committing and discarding changes
As in CVS, committing changes made to the project back into the Subversion repository is a straightforward process. Simply type
svn commit project_item_path -m "reasons_for_committal"
at the Terminal prompt. Alternatively, to commit all changes made to the project type
svn commit project_name -m "reasons_for_committal"
at the prompt. For example, to commit the changes made to the file, Converter.m, type
svn commit Converter.m -m "reasons_for_committal"
To commit all changes made to CurrencyConverter, type
svn commit CurrencyConverter -m "reasons_for_committal"
Always provide a brief and concise committal message to ensure an accurate revision history.
Subversion first checks the repository for any committal transactions in progress. If none are present, it locks the repository to prevent future committals from other users. It then processes your committal request and unlocks the repository after a successful or rejected committal. In case your committal transaction fails, avoid further attempts in order to protect repository integrity. Contact your project administrator to resolve the issue.
Discarding changes made to a project item is also equally straightforward. Type svn revert project_item_name at Terminal prompt to revert to the latest revision of the item in the repository. To revert to a specific revision of the same item, type
svn revert -r revision_number project_item_name
at the prompt.
Exporting the project
Finally, Subversion allows you to export a copy of your project archive for public distribution. Like in CVS, the exported copy does not contain any administrative files, thus preventing it from being accidentally committed back into the repository. Also, Subversion streamlines the process by not requiring a release tag assigned to the project to be exported. Instead, it will export a specified revision of the project archive or, if none is specified, the latest revision of said archive.
To export a copy of the project archive, type
svn export file://$SVNROOT/project_name export_directory_path
at the Terminal prompt. To export a specific revision of the archive, type
svn export -r revision_number file://$SVNROOT/project_name \
export_directory_path
at the prompt. For example, if you want to export the latest revision of CurrencyConverter, type
svn export file://$SVNROOT/CurrencyConverter \
~/Projects/CurrencyConverter_GM
to export the project under the name CurrencyConverter_GM and in the Projects subdirectory of your home directory.
It is recommended that you assign a different name to your exported project. However, if you use the same name as the project archive, make sure to export the project to a different directory. This is to avoid the export process from accidentally overwriting your working copy of the archive.
Subversion and XCode
Since both CVS and Subversion share some of the same subcommands, XCode is capable of supporting either one through its SCM menu. However, many of the SCM operations supported by XCode are geared more towards CVS, being the default tool. But, with some work on your part, you can configure XCode to take advantage of many Subversion features.
Enabling Subversion support
To start managing your XCode project using Subversion, add your project to the repository and check out a working copy using the procedures stated earlier. Open the project into XCode and choose Edit Project Settings from the Project menu to display the Project Info panel. Select Subversion from the drop-down list labeled SCM System. Click on the Edit button to change the current Subversion tool path from /usr/local/subversion/bin/svn to /usr/local/bin/svn (Figure 4). If you skip this step, XCode will display an error informing you that it is unable to locate the Subversion tool. Once you have set the correct tool path, click on the Enable SCM checkbox to set it.
Figure 4. Changing the SCM tool path.
There is nothing wrong with the default tool path of /usr/local/subversion/bin/svn if you happen to have installed Subversion at that particular location. However, the current Subversion installer uses /usr/local/bin as its installation directory, hence the procedure. This could change in future distributions so make sure to read the accompanying release notes before installing or upgrading your copy of Subversion.
The Subversion work cycle in XCode
As mentioned earlier, XCode uses the SCM menu to handle the Subversion work cycle. Each menu item performs the selected transaction by invoking the appropriate Subversion subcommand, many of which are shown in Table 1. Most of the subcommands invoked work on the latest revision of the project archive or its items. Those that work on specific revisions will prompt you for the revision number through an input dialog.
Menu Item Subcommand
SCM Results svn status
Add to Repository svn add
Resolved svn resolved
Commit Changes... svn commit project_item_name -m message
Discard Changes svn revert
Update To svn update -r
Diff With svn diff -r
Get Annotations For svn blame -r
Commit Entire Project svn commit project_name -m message
Update Entire Project svn update project_name
Table 1. The SCM menu items and their SVN subcommands.
Other menu items will also generate the Subversion subcommand corresponding to the selected operation. For instance, choosing Rename from the File menu to rename a project file generates an svn move to rename the same file in the repository archive. Choosing Delete from the Edit menu to remove a project file (both references and item), generates an svn delete, thus removing the file from the archive.
The Info panel (Figure 5) can also generate the appropriate Subversion subcommands by clicking one of the four buttons on the panel. Each command uses the currently selected project file or the project bundle as its input argument.
The Update button generates an svn log, which displays the log report for the selected item. The Compare button generates an svn export to temporarily retrieve the item from the archive. It then launches FileMerge and uses it to compare the contents of the exported item with that from the project. The Diff button generates an svn diff showing the differences between the selected item and its archival version. Finally, the Annotate button generates an svn blame, displaying the revision and author history of the selected item.
Figure 5. The SCM view of the Info panel.
Subversion menu scripts
Unfortunately, the built-in SCM support in XCode is limited and certainly not customizable. Future versions of XCode might address this limitation by redesigning its SCM support as a collection of customizable plug-ins. Each SCM plug-in would then correspond to a specific system such as Subversion, and would allow developers to fine-tune each transaction in a fashion similar to key bindings.
Until than happens, the only way to implement customized SCM transactions is through the XCode Script menu. This menu supports scripts that are written in most shell languages such bash, Python, and Perl. It does not, however, supports scripts written entirely in AppleScript nor JavaScript.
All XCode menu scripts are stored in the directory
/Library/Application Support/Apple/Developer Tools-
/Scripts/10-User Scripts
The scripts are grouped into separate subdirectories, each one corresponding to a category. For instance, the SCM menu scripts featured here are stored in the subdirectory named Subversion.
Listing 2 shows one example of a Subversion menu script. This script first checks the trunk directory of the project for the hidden subdirectory .svn. It then extracts the repository path and project name from the entries file stored in the hidden subdirectory. Afterwards, the script invokes the svnlook tree subcommand and stores the results into the file, svnlook_tree.log. It then uses XCode to display the contents of the log file. A variation of this script is also used to invoke the svnlook history subcommand.
Listing 2. Displaying the repository tree.
#! /bin/bash
#
# Script: svnlook_tree.sh
# Description: Display the tree structure of the project in
# the Subversion repository
#
# -- PB User Script Info --
# %%%{PBXName=Show SVN Tree}%%%
# %%%{PBXInput=None}%%%
# %%%{PBXOutput=SeparateWindow}%%%
#
# update the following environmental variable
export PATH=/usr/local/bin:/usr/local/lib:$PATH
#prepare the following shell variables
SVNTAG="repos="
SVNURL="url="
SVNDIR="build/svn"
SVNLOG="$SVNDIR/svnlook_tree.log"
SVNERR="$SVNDIR/svnlook_tree.err"
#check for the following hidden directory
if [ -d ".svn" ];
then
#retrieve the repository key
SVNGREP=`grep $SVNTAG .svn/entries`
#retrieve the repository location
SVNROOT=`echo $SVNGREP | awk -F= '{ print $2 }'`
SVNROOT=`echo $SVNROOT | awk -F"\"" '{ print $2 }'`
#remove the URL tag
SVNROOT=`echo $SVNROOT | awk -F"//" '{ print $2 }'`
#retrieve the project key
SVNGREP=`grep $SVNURL .svn/entries`
#retrieve the project name
SVNPROJ=`echo $SVNGREP | awk -F= '{ print $2 }'`
SVNPROJ=`echo $SVNPROJ | awk -F"\"" '{ print $2 }'`
SVNPROJ=`echo $SVNPROJ | awk -F"/" '{ NOM=NF-1 ; print $NOM }'`
#check for the following directory
if [ ! -d $SVNDIR ];
then
mkdir -p $SVNDIR
fi
#retrieve the repository key structure
svnlook tree $SVNROOT $SVNPROJ --show-ids 1> $SVNLOG 2> $SVNERR
if [ ! -s $SVNERR ];
then
rm -Rf $SVNERR
fi
#construct the full path to the log file
SVNLOG=`pwd`/$SVNLOG
SVNLOG="OS X"`echo $SVNLOG`
SVNLOG=`echo ${SVNLOG//\//:}`
SVNLOG="\"$SVNLOG\""
#open the file using XCode
osascript <<-APPLESCRIPT
tell application "Finder"
set fileref to get file $SVNLOG as string
tell application "XCode"
activate
open file fileref
end tell
end tell
APPLESCRIPT
else
echo "This project is currently not under SCM by Subversion."
fi
A second example of a Subversion menu script is shown in Listing 3. This script also performs the same checks as the previous one. Afterwards, it queries the user for a backup filename and a location where to store the backup. It then invokes the svnadmin dump subcommand to create the backup file at the specified location. A variation of this script is also used to invoke the svnadmin hotcopy subcommand.
Listing 3. Creating a repository backup file.
#! /bin/bash
#
# Script: svnadmin_dump.sh
# Description: Create a backup image of the SVN repository.
#
# -- PB User Script Info --
# %%%{PBXName=Create Backup Image}%%%
# %%%{PBXInput=None}%%%
# %%%{PBXOutput=SeparateWindow}%%%
#
# update the following environmental variable
export PATH=/usr/local/bin:/usr/local/lib:$PATH
#prepare the following shell variables
SVNTAG="repos=" #the repository tag
SVNURL="url=" #the URL tag
SVNOUT=svn`date "+%m%d%y%H%M%S"`.bak #default output file
SVNMSG="Save the file in:" #output prompt
#check for the following hidden directory
if [ -d ".svn" ];
then
#prompt the user for the output path
SVNBAK=`%%%{PBXUtilityScriptsPath}%%%/AskUserForNewFileDialog "$SVNMSG" "$SVNOUT"`
#validate the output path
SVNCNT=`echo $SVNBAK | awk -F"/" '{ print NF }'`
if [ "$SVNCNT" -gt "1" ];
then
#start the backup process
#------
#retrieve the repository key
SVNGREP=`grep $SVNTAG .svn/entries`
#retrieve the repository location
SVNROOT=`echo $SVNGREP | awk -F= '{ print $2 }'`
SVNROOT=`echo $SVNROOT | awk -F"\"" '{ print $2 }'`
#remove the URL tag
SVNROOT=`echo $SVNROOT | awk -F"//" '{ print $2 }'`
#invoke the svnadmin command
svnadmin dump $SVNROOT -q > $SVNBAK
fi
else
echo "This project is currently not under SCM by Subversion."
fi
Menu scripts, however, do have some inherent problems. Since the Script menu is enabled only when XCode is displaying a project, it makes it unfeasible to create a menu script that will invoke an svn checkout transaction. Also, if a menu script contains a call to one of its built-in utility scripts, specifically those that displays a user-interface, and to the osascript tool as well, XCode hangs consistently whenever it rebuilds its Script menu. Separating those two calls is the only way of avoiding the hang condition.
Concluding Remarks
Subversion is a source-code management system that improves upon the venerable CVS in numerous ways. It supports most of the same subcommands while providing more relevant ones to do other transactions. It also supports binary file formats, provides better handling of project subdirectories, and has backup and restore features.
The XCode development environment integrates rather well with Subversion. Since both uses nearly the same subcommands, XCode was able to use Subversion without any major issues. More advanced Subversion features can be accessed through XCode by providing the appropriate menu scripts.
[Ed. Note - As shown, Subversion is an incredible tool. But note that it's not only for source code! Mac techs will be seeing a lot more Subversion in their future. Also, while the underlying principals are important to understand, if you ever need a quick-and-dirty svn check out, or are just pre-disposed to the GUI, a new graphical Subversion client just shipped for the Mac. ZigZig Software introduced ZigVersion during WWDC 2006 - after Jose wrote this article! Find out more at http://www.zigzig.com]
Bibliography and References
Collins-Sussman, Ben, Brian Fitzpatrick, C. Michael Pilato. Version Control with Subversion. Revision 1337. Copyright 2002, 2003, 2004, 2005. Ben Collins-Sussman BrianW Fitzpatrick C. Michael Pilato.
Wikipedia. Subversion. In Wikipedia, the free encyclopaedia. The Wikipedia Community. 2006 June 7. Online: http://en.wikipedia.org/wiki/Subversion_%28software%29.
Apple Computers. "Appendix A: Using Subversion". XCode 2.2 User Guide. Copyright 2004, 2005. Apple Computers, Inc.
Apple Computers. "Using Scripts to Customise XCode". XCode 2.2 User Guide. Copyright 2004, 2005. Apple Computers, Inc.
JC is a freelance engineering consultant and writer currently residing in North Vancouver, British Columbia. He divides his time between writing technical articles, and teaching origami at the local district's public library. He can be reached at <anarakisware@cashette.com>.
