= 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]]

[[Image(300px-SVN_model.png)]]

== 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.

[[Image(300px-SVN_revision.png)]]

== First things to do ==
'''Create a repository'''

{{{
svnadmin create $HOME/repos
}}}
This creates a repository under '$HOME/repos'.

Note that $HOME is your home-directory on Cypress.

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

'''Testing your repository'''

On Cypress,
{{{
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....'''



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== Tutorial::Accessing your Repository over Network ==
To access your Repository on Cypress through ssh from other hosts,

{{{
svn co svn+ssh://USERNAME@cypress1.tulane.edu/HOME_DIRCTORY/repos/project1 ./project1
}}}

You will be asked for typing your password.

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

To see the path of your home directory, on Cypress
{{{
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 Cypress,
{{{
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
}}}