Manage Source Code Versions with Subversion
Updated by Linode Written by Linode
DeprecatedThis guide has been deprecated and is no longer being maintained.
Subversion (SVN) is a centralized version control system. Used by software developers to track changes during the production and maintenance of a project. SVN is a familiar and standard component in many development tool chains. Subversion was developed as a replacement for the Concurrent Versions System (CVS). SVN attempts to fix many of the major problems with CVS without requiring any paradigm shifts in the way software is developed:
- Commit operations are atomic. When a user saves a revision and sends it to the
svnserver, the server process will not put the commit data in the server’s database until specifically told to.
- Files and directories can be renamed while still maintaining a coherent record of the files.
Because Subversion uses a centralized architecture, in order to collaborate with others you must have a server to host the project. This guide outlines both the installation and setup of Subversion as well as the basic use of
There are many options for accessing and managing Subversion repositories on local systems. You can use any Subversion client to connect to and interact with the repositories that you configure on your Linode. This guide will use standard shell commands and the
svn utility to connect to Subversion repositories.
Before You Begin
Familiarize yourself with our Getting Started guide and complete the steps for setting your Linode’s hostname and timezone.
Complete the sections of our Securing Your Server to create a standard user account, harden SSH access and remove unnecessary network services.
Update your system:
sudo apt-get update && sudo apt-get upgrade
NoteThe steps in this guide require root privileges. Be sure to run the steps below as
rootor with the
sudoprefix. For more information on privileges, see our Users and Groups guide.
Subversion is included in the software repositories of most major Linux distributions. Installing the
subversion package installs all of the tools that you need to administer and maintain your Subversion repositories, as well as client utilities.
Debian and Ubuntu
Install the Subversion repository:
apt-get install subversion
CentOS and Fedora
yum install subversion
svn using pacman:
pacman -S subversion
Create a Subversion Repository
Create a directory to host your Subversion repositories:
mkdir -p /srv/svn/
svnadminto create a new SVN repository:
svnadmin create /srv/svn/subversion-test
In this example, we’ve created a single
subversion-testrepository in the
/srv/svn/directory. Because SVN allows you to only check out the specific portions of the repository you need, administrators will frequently create a single repository for a project and developers will only check out and work on the portions of the project that they need.
Manage Subversion Repositories
svnadmin tool provides a number of additional commands which are useful for administering and maintaining a Subversion repository.
Verify Repository Integrity
Check the integrity of a repository:
svnadmin verify /srv/svn/subversion-test
Upgrade a repository’s data store to the latest version of the schema:
svnadmin upgrade /srv/svn/subversion-test
Back Up a Repository
In cases where you’re manipulating Subversion’s data store (e.g. an upgrade or moving to a new machine), it’s useful to create a dump of your Subversion repository to store as a backup. By default, this contains the full content of each commit.
Create a directory to store your backups:
Create an svn dump:
svnadmin dump /srv/svn/subversion-test > /var/svn/subversion-test-1259853077.svn
In this example, the repository is located at
/srv/svn/subversion-testand the dump file is located at
/var/svn/subversion-test-1259853077.svn. To make it easier to organize, name your svn backups with file names that refer to the revision or time when the backup was created, as well as the name of the repository contained in the backup.
You can also save your backups in an incremental format, which outputs the differences between revisions rather than full copies of each revision:
svnadmin dump /srv/svn/subversion-test --incremental > /var/svn/subversion-test-1259853077.svn
Create an empty repository:
svnadmin create /srv/svn/subversion-test-backup
Load the backup into the empty repository:
svnadmin load /srv/svn/subversion-test-backup < /var/svn/subversion-test-1259853077.svn
NoteIf you store critical information in a Subversion repository, you may wish to create backups automatically using a cron job.
Use Subversion for Version Control
By default, Subversion will track the version history for all of the files in a directory tree. Furthermore, Subversion does not specify or require any particular workflow or repository layout. However, many users organize their repositories into three directories:
trunk: Where core development and changes are stored. A full copy of the project’s source is located in the trunk directory.
tags: Where snapshots of specific revisions, versions, or other meaningful points in the project are kept for future reference. Tags are frequently used to mark release versions.
branches: Where copies of the project are stored in cases where developers need to track ongoing and potentially divergent revision histories. Branches are frequently used to manage the ongoing maintenance of legacy releases and host experimental development of new features.
Branches and tags are created using the
svn copy command. Because Subversion tracks the history of a file independently of a filename or location on the file system, copies share history. As a result, branches and tags don’t increase the amount of space a repository consumes.
Subversion is a centralized version control system, which means that in order to perform version control operations on your local copy you need to have an active connection to the server that hosts the repository. While you can add, move, and delete files without a network connection, committing changes to the repository requires an active connection to the repository. By convention, the local copy of your repository is called the checkout and individual sets of changes are called commits.
Subversion also makes it possible for you to only check out portions of a repository. If you only need to work with the
trunk portion of the repository, you can specify the URL to only that path of the repository.
Common Subversion Commands
If you have prior experience using a CVS, you may already be familiar with many of the commands used for interacting with Subversion repositories. Subversion aims to be compatible with CVS user workflows.
svn checkout [repository-path]or
svn co [repository-path]. The
[repository-path]refers to the location of the remote repository. You must provide the location of the repository in the form of a URL.
If you want to check out the repository at a specific revision, use the
-r [revision-number] option with the
svn co command to specify a particular revision.
svn updownloads all changes and brings your copy up to date with any changes that have been committed since your last update. Run
svn updatefrequently to avoid working on an out-of-date codebase and complicated commits.
svn commitsaves the changes to the current checkout and creates a new commit on the server for this change-set. When invoked without arguments, this opens your default text editor so that you can enter a commit message. If you want to specify a commit message from the command line, use
svn commit -m "[commit-message]".
svn addstages a previously untracked file for the next commit.
svn deleteremoves a file from the next commit and deletes it from the filesystem. This command should be used instead of your system’s
rmcommand to allow Subversion to track the removal of files. Subversion also provides the
svn delcommands, which are functionally identical to
svn copycreates a copy of a file in a new location and name in the repository. In these circumstances Subversion treats the history of both files (previous to the copy) as a single series of changes.
svn movemoves the specified file or files to a new location while retaining the history, despite the change in file name. Functionally, this is equivalent to running the
svn copycommand followed by the
svn diffdisplays the differences between two revisions in the repository. Without any arguments it displays the differences between the current status of the working copy (i.e. checkout) and the latest version of the repository.
svn loggenerates and displays the revision history of an the current directory in the filesystem. You may also specify a specific file name, for instance
svn log roster.txtproduces the revision history for the
roster.txtfile. You can also use
svn logto access the revision history of a remote repository:
svn log http://example.com/repos/subversion-test/files/txt/ roster.txt data.txt
In this example,
svn logdisplays the revision history of the files
data.txtin the remote repository.
Access Subversion over HTTP
If you and your developers only need to access your repository over SSH with the
ssh+svn:// protocols, skip the remainder of this guide.
If you need to access your repository over the
https:// protocols, configure Apache to host your Subversion repository.
Install Apache and mod_dav_svn
Developers frequently access Subversion repositories via the SSH protocol and manage permissions and authentication credentials using OpenSSH and system user accounts. This can be difficult to manage if you are hosting a large number of repositories with a large number of users on a single server. For these cases, many users provide access to their repositories using the “WebDAV” protocol over HTTP or HTTPS with the Apache Web Server.
Install the Apache module
Debian and Ubuntu:
apt-get install libapache2-svn apache2
systemctl restart apache2
CentOS and Fedora:
yum install mod_dav_svn httpd
Arch and Gentoo:
mod_dav_svnis installed by default with the Apache package.
Gentoo users will need to compile the
subversionpackage with the following
Configure Repository Permissions
To permit the Apache module
mod_dav_svn to provide access to your Subversion repository, allow the web server process to access the repository.
On Debian and Ubuntu systems, Apache runs under the
chown -R www-data /srv/svn/subversion-test
On CentOS and Fedora systems, Apache runs as
chown -R apache /srv/svn/subversion-test chown -R httpd /srv/svn/subversion-test
On Arch Linux, Apache runs under the
chown -R nobody /srv/svn/subversion-test
Add a User Group
If local system accounts need to access the repository, add those users to the group that has ownership of the given files. The following example creates a new group and adds a number of users to a group. You can then change the group ownership of the repository as described above.
Create a new group:
Add the example users,
svnusergroup.\ (either create these users first with
useraddor replace them with usernames already on your system):
usermod -G svnuser user1 usermod -G svnuser user2 usermod -G svnuser user3
svnusergroup ownership of the repository:
chgrp -R svnuser /srv/svn/subversion-test
In order to avoid permission conflicts with multiple users, set the sticky bit (
+s) for the entire repository in a recursive (
chmod -R +s /srv/svn/subversion-test
CautionThe sticky bit allows all users with access to the files (i.e. members of the group) to create files that are owned by the user or group that owns the directory, rather than by their own default user and group. This also allows users to execute scripts in these directories as the user that owns them, and thus poses a potential security risk. See our Linux Users and Groups guide for more information.
Configure the Apache Web Server
This section demonstrates configuration for Debian and Ubuntu systems. Similar steps will work on other distributions. Please adjust accordingly.
In this example,
subversion-test corresponds to the name of the repository, and
/srv/www/svn.example.com is a directory distinct from your Subversion repositories. Maintaining a separate
htpasswd for each repository hosted on your Linode makes sense if each repository is used by a distinctly different set of users. Conversely, if each repository that you administer is used by a subset of a larger group of users you may wish to configure user groups to organize your users’ access.
mod_davApache modules. This will make it possible to use the
WebDAVsystem to access the Subversion repository.
a2enmod dav a2enmod dav_svn
systemctl restart apache2
Configure HTTP AUTH passwords for Subversion users. You can read more about HTTP AUTH in our Apache Authentication guide. Store your
htpasswdfile for your Subversion repositories in a location such as:
Manage a Single Repository
In a text editor, open
/etc/apache2/sites-available/svn.example.com.confand add the following content. Replace
svn.example.comwith the public IP address or FQDN of your Linode:
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<VirtualHost *:80> ServerAdmin email@example.com ServerName svn.example.com ErrorLog /srv/www/svn.example.com/logs/error.log CustomLog /srv/www/svn.example.com/logs/access.log combined <Location /> DAV svn SVNPath /srv/svn/subversion-test AuthType Basic AuthName "Subversion Repository" AuthUserFile /srv/www/svn.example.com/subversion-test.htpasswd Require valid-user </Location> </VirtualHost>
This configuration forwards all requests for
mod_dav_svn. This will provide an overview of the most recent revision of the repository within a web browser. Note that this setup provides unencrypted access to your repository over
For a secure connection, configure Apache to serve content with SSL. Once your certificate files are in place, configure the virtual host to respond to requests on port
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<VirtualHost *:443> ServerAdmin firstname.lastname@example.org ServerName svn.example.com ErrorLog /srv/www/svn.example.com/logs/error.log CustomLog /srv/www/svn.example.com/logs/access.log combined SSLEngine On SSLCertificateFile /etc/apache2/ssl/apache.pem SSLCertificateKeyFile /etc/apache2/ssl/apache.key <Location /> DAV svn SVNPath /srv/svn/subversion-test AuthType Basic AuthName "Subversion Repository" AuthUserFile /srv/www/svn.example.com/subversion-test.htpasswd Require valid-user </Location> </VirtualHost>
Create the log file directory specified in the virtual host block:
Disable the default site and enable the new site configuration:
a2dissite 000-default.conf a2ensite svn.example.com
systemctl restart apache2
Navigate to your Linode’s IP or FQDN in a web browser; you should see a brief overview of the most recent version in your web browser.
Manage Multiple Repositories
There are two methods for specifying Subversion repositories to
mod_dav_svn. The first is using the
SVNParentPath. This directive is useful if you need to provide multiple repositories, located in adjacent directories. For example:
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<VirtualHost *:80> ServerAdmin email@example.com ServerName svn.example.com ErrorLog /srv/www/svn.example.com/logs/error.log CustomLog /srv/www/svn.example.com/logs/access.log combined <Location /> DAV svn SVNParentPath /srv/svn AuthType Basic AuthName "Subversion Repository" AuthUserFile /srv/www/svn.example.com/shared.htpasswd Require valid-user </Location> </VirtualHost>
All repositories located within
/srv/svn on the file system will be accessible over HTTP at URLs that begin with
As another option, you can specify multiple repositories using the
SVNPath directive in multiple
location blocks. In the following example, the Subversion repository located on the file system at
/srv/svn/subversion-test will be accessible over HTTP at the URL
http://example.com/subversion-test, while the repository at
/srv/svn/subversion-test will be accessible at
http://example.com/subversion-test. In this example each repository will use a separate set of user credentials.
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<VirtualHost *:80> ServerAdmin firstname.lastname@example.org ServerName example.com ServerAlias www.example.com DocumentRoot /srv/www/example.net/public_html/ ErrorLog /srv/www/example.com/logs/error.log CustomLog /srv/www/example.com/logs/access.log combined <Location /subversion-test> DAV svn SVNPath /srv/svn/subversion-test AuthType Basic AuthName "Morris Subversion Repository" AuthUserFile /srv/www/example.com/subversion-test.htpasswd Require valid-user </Location> <Location /subversion-test> DAV svn SVNPath /srv/svn/subversion-test AuthType Basic AuthName "Molly Subversion Repository" AuthUserFile /srv/www/example.com/subversion-test.htpasswd Require valid-user </Location> </VirtualHost>
Provide Read-Only Access
All of the preceding cases have required that a user log in before accessing your repository. If you would like to allow read only public access to your repository, add
LimitExcept blocks to your virtual hosts:
- Apache Virtual Host Configuration
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<VirtualHost *:80> ServerAdmin email@example.com ServerName svn.example.com ErrorLog /srv/www/svn.example.com/logs/error.log CustomLog /srv/www/svn.example.com/logs/access.log combined <Location /> DAV svn SVNPath /srv/svn/subversion-test AuthType Basic AuthName "Subversion Repository" AuthUserFile /srv/www/svn.example.com/subversion-test.htpasswd <LimitExcept GET PROPFIND OPTIONS REPORT> Require valid-user </LimitExcept> </Location> </VirtualHost>
You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.
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