Thursday, January 26, 2012

Subversion Tutorial: 10 Most Used SVN Commands with Examples

SVN stands for Subversion.
Subversion is a free/open-source version control system. Subversion manages files and directories over time. A tree of files is placed into a central repository. The repository is much like an ordinary file server, except that it remembers every change ever made to your files and directories. This allows you to recover older versions of your code, or examine the history of how your code was changed.
This article explains some basic SVN commands with examples.

SVN Working Copy

SVN is a repository that holds all our versioned data, which is also called as SVN server. SVN client program which manages local reflections of portions of that versioned data which is called as working copy. SVN client can access its repository across networks. Multiple users can access the repository at the same time.

1. SVN Checkout – Create working copy

Checkout command is used to download sources from SVN repository to working copy. If you want to access files from the SVN server, checkout is the first operation you should perform.
SVN checkout creates the working copy, from where you can do edit, delete, or add contents. You can checkout a file, directory, trunk or whole project. To checkout you should know URL of the components you want to checkout.

$ svn checkout/co URL PATH
  • URL is the URL of the components to checkout
  • If PATH is omitted, the basename of the URL will be used as the destination. If multiple URLs are given each will be checked out into a subdirectory of PATH, with the name of the subdirectory being the basename of the URL.
The following example checks out the directory to the given target directory.
$ svn co /home/sasikala/cfg/
A    /home/sasikala/cfg/ftp_user.cfg
A    /home/sasikala/cfg/inventory.cfg
A    /home/sasikala/cfg/email_user.cfg
A    /home/sasikala/cfg/svn-commands
Checked out revision 811.

$ ls /home/sasikala/cfg
.  ..  .svn  email_user.cfg  ftp_user.cfg  inventory.cfg  svn-commands
When you do a checkout, it creates hidden directory named .svn, which will have the repository details.

2. SVN Commit – Save changes to the repository

Whenever you do changes to the working copy, it will not reflect in SVN server. To make the changes permanent, you need to do SVN commit.

$ svn commit -m "log messages"
Explain why you are changing the file in the -m option.
For example, in my working copy, the file named “svn-commands” has the following content.
$ cat /home/sasikala/cfg/svn-commands

$ ls -l /home/sasikala/cfg/svn-commands
-rw-r--r--  1 root root 41 Apr 16 11:15 svn-commands
I made a change in this file (for example, making this file empty).
$ ls -l svn-commands
-rw-r--r--  1 root root 0 Apr 16 11:20 svn-commands
Now commit the file to make the changes permanent in the server.
$ svn commit -m "Making the file empty" svn-commands
Sending        svn-commands
Transmitting file data .
Committed revision 813.
After this whenever you update your working copy or checkout, the changes will appear in the server.

3. SVN List – Lists directory entries

svn list is useful when you want to view the content of the SVN repository, without downloading a working copy.

$ svn list
The following example lists all the files available in the given URL in the repository without downloading a working copy. When you execute svn list command with –verbose option it displays the following information.
  • Revision number of the last commit
  • Author of the last commit
  • Size (in bytes)
  • Date and time of the last commit
$ svn list --verbose
 16 sasikala 28361  Apr 16 21:11 README.txt
 21 sasikala  0  Apr 18 12:22 INSTALL
 22 sasikala  Apr 18 10:17 src/

4. SVN Add – Add a new file to SVN repository

When you want to add a new file (or directory) to the repository you need to use SVN add command. The repository will have newly added file, only when you do SVN commit. Now let us add a new file called “sureshstuff” to our repository.
  • Create a file in local working copy
  • $ ls -l /home/sasikala/cfg/sureshstuff
    -rw-r--r--  1 sasikala root 8 Apr 16 11:33 sureshstuff
  • Add the file into SVN repository
  • svn add filename will add the files into SVN repository.
    $ svn add sureshstuff
    A        sureshstuff
  • Commit the added the file
  • Until you commit, the added file will not be available in the repository.
    $ svn commit -m "Adding a file sureshstuff" sureshstuff
    Adding         sureshstuff
    Transmitting file data .
    Committed revision 814.

5. SVN Delete – Removing a file from repository

SVN delete command deletes an item from the working copy (or repository). File will be deleted from the repository when you do a SVN commit.
$ svn delete URL
Now let us remove the recently created file called “sureshstuff”.
$ svn delete sureshstuff
D         sureshstuff

$ svn commit -m "Removing sureshstuff file" sureshstuff
Deleting       sureshstuff
Committed revision 814.
Now you can do svn list and check whether the file was deleted from the repository.

6. SVN Diff – Display the difference

SVN diff displays the differences between your working copy and the copy in the SVN repository. You can find the difference between two revisions and two paths etc.,
$ svn diff filename

$ svn -r R1:R2 diff filename
The above example compares the filename@R1 and filename@R2.
Now the content of the file sureshstuff looks like this,
$ cat /home/sasikala/cfg/sureshstuff
I edited the content of sureshstuff file from testing to tester, which is shown below using the svn diff command.
$ svn diff sureshstuff
Index: SURESHstuff
--- sureshstuff   (revision 815)
+++ sureshstuff   (working copy)
@@ -1 +1 @@

7. SVN Status – Status of the working copy

Use svn status command to get the status of the file in the working copy. It displays whether the working copy is modified, or its been added/deleted, or file is not under revision control, etc.

$ svn status PATH
The following example shows the status of my local working copy,
$ svn status /home/sasikala/cfg
M     /home/sasikala/cfg/ftp_user.cfg
M       /home/sasikala/cfg/sureshstuff
‘M’ represents that the item has been modified. “svn help status” command will explain various specifiers showed in SVN status command.

8. SVN Log – Display log message

As we discussed in the beginning of this article, SVN remembers every change made to your files and directories. To know all the commits made in a file or directory, use SVN log command.

$ svn log PATH
The following displays all the commits made on sureshstuff file
$ svn log sureshstuff
r815 | sasikala | 2011-04-16 05:14:18 -0700 (Sat, 16 Apr 2011) | 1 line

Adding a file sureshstuff
Since we made only one commit in the file sureshstuff, it shows only one log message with the details.

9. SVN Move – Rename file or directory

This command moves a file from one directory to another or renames a file. The file will be moved on your local sandbox immediately (as well as on the repository after committing).
$ svn move src dest
The following command renames the file “sureshstuff” to “tgs” in a single stroke.
$ svn move sureshstuff tgs
A         tgs
D         sureshstuff

$ ls
.#  ..  .svn  email_user.cfg  ftp_user.cfg  inventory.cfg  tgs
Now the file is renamed only in the working copy, not in the repository. To make the changes permanent, you need to commit the changes.
$ svn commit -m "Renaming sureshstuff to tgs" tgs
Adding         tgs
Transmitting file data .
Committed revision 816.

10. SVN Update – Update the working copy.

svn update command brings changes from the repository into your working copy. If no revision is specified, it brings your working copy up-to-date with the HEAD revision. Otherwise, it synchronizes the working copy to the revision given in the argument.
Always before you start working in your working copy, update your working copy. So that all the changes available in repository will be available in your working copy. i.e latest changes.

$ svn update PATH
In case some other user added/deleted file in URL,, your working copy will not have those files by default, until you update your working copy.
$ svn update
A  new/usercfg
A  new/webcfg
Updated to revision 819.
In the above svn update command output, A represents that this file is “Added” to the working copy.