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A Short SVN Tutorial

Introduction

A repository is a storage area containing all files and directories under version control. The repositories can be local pathnames if all users of the repository have access to that filesystem. They can be remote repositories with different syntax. For this course your repository syntax is:

• /home/svn/490.2009/groupname for in department access,
  So for checking out your project you need to type:
  svn checkout file:///home/svn/490.2009/groupname
• /username@login.ceng.metu.edu.tr/home/svn/490.2009/groupname for remote access via ssh.
  So for checking out your project you need to type:
  svn checkout svn+ssh://username@login.ceng.metu.edu.tr/home/svn/490.2009/groupname

In this document we will assume that two users user1 and user2 use the system, and the group name is project.

Creating the Initial Module

For starting to use svn, first you need to import your project. For example, if you have the following listing in your project directory:

$ cd /home/user1/mytree
$ ls -R
.:
src/  web/

./src:
main.c  main.h  Makefile

./web:
index.html

Then you can import your project using the following command:

$ cd /home/user1/
$ svn import mytree file:///home/svn/490.2009/project -m "Initial import"
Adding         mytree/src
Adding         mytree/src/main.c
Adding         mytree/src/main.h
Adding         mytree/src/Makefile
Adding         mytree/web
Adding         mytree/web/index.html

Committed revision 1.

You can list the files in the repository by using the command:

$ svn list file:///home/svn/490.2009/project
src/
web/

Thus, as can be seen the files under the directory mytree is copied under the directory project in the repository. To start on working on the working copy of the project, you first need to checkout your project.

$ svn checkout file:///home/svn/490.2009/project
A    project/src
A    project/src/main.c
A    project/src/main.h
A    project/src/Makefile
A    project/web
A    project/web/index.html
Checked out revision 1.

By the checkout command a working copy of your project is copied to your current directory under the directory project.

Basic Usage

Most of the time you will use the following steps:

• Update your copy (if you do not have a working copy you need to checkout as given in the previous section).
• Make changes to the files.
• Commit your changes.

A sample session may be as the following:

$ cd /home/user1/project
$ svn update
U    src/main.c
U    web/index.html
Updated to revision 6.
$ vi web/index.html
<...Make your changes...>
$ vi src/main.h
<...Make your changes...>
$ svn commit -m "changes by user1"
Sending        src/main.h
Sending        web/index.html
Transmitting file data ..
Committed revision 7.

Multiple Developers

When multiple developers work on the same project, it is likely that a file is changed by another developer until you commit your changes. Assume that in the following scenario user1 and user2 updated the same version of the project. They both started to modify main.c. user2 commits her/his changes before user1. Then user1 tries to commit her/his own chages.

$ svn commit
Sending        src/main.c
svn: Commit failed (details follow):
svn: Out of date: '/project/src/main.c' in transaction '9-1

user1 should first update her/his working copy to resolve the conflicts.

$ svn update
C    src/main.c
Updated to revision 9.

When user1 updates her/his copy there are four different version of main.c. main.c.mine, the file that contains the changes by user1. main.c.r8, 8th version of the file (previous version). main.c.r9, 9th version of the file (the version that user2 committed). main.c, the file which contains both changes by user1 and user2.

$ cat src/main.c
#include <stdio.h>

int main (int argc, char **argv)
{
<<<<<<< .mine
        int a = 7;
        printf("%d\n", a);
=======
        int a = 5;

        printf("%d\n", a);
>>>>>>> .r9
        return 0;
}

user1 should modify the portion between «««< .mine and »»»> .r9 to resolve the conflict. After the conflicts are resolved user1 procedes as follows:

$ svn resolved src/main.c
Resolved conflicted state of 'src/main.c'
$ svn commit -m "Discarding the changes by user2"
Sending        src/main.c
Transmitting file data .
Committed revision 10.

Adding, Removing, Renaming a File

If you want to make a change in the tree structure, you cannot do it just by using a commit command. For example, user1 creates a new file src/project.c and in the working directory first adds and then commits the file.

$ svn add src/project.c
A         src/project.c
$ svn commit
Adding         src/project.c
Transmitting file data .
Committed revision 11.

For creating directories you first create the directory and then add that directory to the repository:

$ mkdir doc
$ vi doc/project.doc
<...Edit your file...>
$ svn add doc
A         doc
A         doc/project.doc
$ svn commit
Adding         doc
Adding         doc/project.doc
Transmitting file data .
Committed revision 12.

Or you can directly create a directory in the repository:

$ svn mkdir lib
A         lib
$ svn commit
Adding         lib

Committed revision 13.

For removing files or directories you can use the delete command:

$ svn delete lib
D         lib
$ svn commit
Deleting       lib

Committed revision 14.

For moving files or directories you can use the move command:

$ svn move src/main.c src/Main.c
A         src/Main.c
D         src/main.c
$ svn commit
Adding         src/Main.c
Deleting       src/main.c

Committed revision 15.