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= Version Control with Subversion (svn) =
== What is SVN? ==
* A free/open-source version control system.
* Managing files and directories over time, placed into a central repository.
* The repository remembers every changes ever made to the files and directories.
* Accessible across networks, allowing to be used on different computers.
* Runs on Many platforms.

[http://subversion.apache.org Home Page]

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== Good things... ==
* If you develop a software with some other people, it keeps track of who did what when and where changes.
   * even if you develop a software yourself...
* When you made a stupid change and screwed up ....
   * Allows you to go back. 
   * Revert to a previous revision of a file/directory.

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== First things to do ==
* Create a repository on ''Cypress''
 svnadmin create $HOME/repos
This creates a repository under '$HOME/repos'.

Note that $HOME is your home-directory on ''sphynx''. 

Once you did this, you don't have to do this again.  Do not delete '$HOME/repos' !!!

* Testing your repository
On ''sphynx'',
 mkdir mywork
 cd mywork
 mkdir project1
 echo "This is README.txt" > README.txt 
 svn import file:///$HOME/repos/project1 -m"initial import"
Now you have ''project1'' in your repository.

Delete ''project1'' then checkout ''project1'' from the repository, 
 cd ..
 rm -rf project1
 svn co file:///$HOME/repos/project1 ./project1

=== Working with SVN ===
* To download files in a repository, use ''''svn checkout'''' / ''''svn co'''' command.
* If you made some changes to the files in your local machine and want to upload these to the repository, use ''''svn commit'''' command.
* If you have files on your local machine and want to update these to the latest version in the repository, use ''''svn update'''' command.
* If you want to add a file/direcotry, use ''''svn add'''' and commit.
* If you want to delete a file/directory, use ''''svn delete'''' and commit.

=== What to Control ===
* Source Code
* Documents
* Variable data
* Anything you want to share that isn't essentially static data.
'''Do not upload.... Large sets of binary files; images, movie, music....'''

=== Accessing your Repository over Network ===
To access your Repository on ''sphynx' through ''ssh'' from other hosts,
 svn co svn+ssh://''USERNAME''@sphynx.ccs.tulane.edu/''HOME_DIRCTORY''/repos/project1 ./project1

You will be asked for typing your password on ''sphynx''.

''USERNAME'' and ''HOME_DIRCTORY'' are your login user name and home directory on ''sphynx''. 

To see the path of your home directory, on ''sphynx''
 cat $HOME

* Using svn-client software with GUI
** There are Windows Versions and Mac OS versions.
***[http://svn-ref.assembla.com/windows-svn-client-reviews.html Client Software Review]

=== Try using Your Repository ===
==== Check out data ====
Somewhere on ''sphynx'',
 svn co file:///$HOME/repos/project1 ./project1
go into '''project1''' directory.
 cd project1

look at files
 ls

==== Edit README.txt ====
Edit '''README.txt''' to add your message.

then commit it.
 svn commit -m"your message"


==== When you made a stupid change or delete a file by mistake ====
You can revert to a previous version. 

To look at the log
 svn log

If you want to download version 1,
 svn -r 1 update

When you delete '''README.txt by mistake, 
 rm '''README.txt'''

See the file you deleted does not exist.
 ls

Download the missing file,
 svn update

==== Add files ====
Make a new file, then add it to svn by
 svn add NEW_FILE_YOU_MADE

then
 svn commit -m"your message"

==== Check status ====
To check the status
 svn stat

To see the difference between the repository and your working version
 svn diff

==== Upload ====
To upload your working version to the repository,
 svn commit -m"comment for current version"

Look at the status and difference
 svn stat
 svn diff

==== Help ====
 svn help