Here's an opportunity to play with Subversion in some
hands-on examples. The Subversion commands demoed here are just
small examples of what Subversion can do; see Chapter 3 in
the Subversion Book for full explanations of each.
Make a Repository
The Subversion client has an abstract interface for
accessing a repository. Three
(RA) implementations currently exist as libraries. You can see
which methods are available to your svn client like so:
$ svn --version
svn, version 1.0.4 (r9844)
compiled May 23 2004, 14:04:22
Copyright (C) 2000-2004 CollabNet.
Subversion is open source software, see http://subversion.tigris.org/
This product includes software developed by CollabNet (http://www.Collab.Net/).
The following repository access (RA) modules are available:
* ra_dav : Module for accessing a repository via WebDAV (DeltaV) protocol.
- handles 'http' scheme
- handles 'https' scheme
* ra_local : Module for accessing a repository on local disk.
- handles 'file' scheme
* ra_svn : Module for accessing a repository using the svn network protocol.
- handles 'svn' scheme
If you don't see ra_local, it probably means that Berkeley
DB (or relevant database back-end) wasn't found when compiling
your client binary. To continue with these examples, you'll
need to have ra_local available.
Start by creating a new, empty repository using the
$ svnadmin create myrepos
Let's assume you have a directory someproject
which contains files that you wish to place under version
Once the repository exists, you can initially import your
data into it, using the ra_local access method (invoked by using
$ svn import someproject file:///absolute/path/to/myrepos/trunk/someproject
Committed revision 1.
The example above creates a new directory tree
trunk/someproject in the root of the repository's
filesystem, and copies all the data from
someproject into it.
Make Some Working Copies
Now check out a fresh
working copy of your
project. To do this, we specify a URL to the exact directory
within the repository that we want. The parameter after the
URL allows us to name the working copy we check out.
$ svn checkout file:///absolute/path/to/myrepos/trunk/someproject wc
Now we have a working copy in a local directory called
wc, which represents the location
/trunk/someproject in the repository (assuming
the repository's root is file:///absolute/path/to/myrepos.)
For the sake of example, let's duplicate the working copy,
and pretend it belongs to someone else:
$ cp -R wc wc2
From here, let's make some changes within our original
$ cd wc
$ echo "new text" >> bar # change bar's text
$ svn propset color green foo # add a metadata property to foo
$ svn delete baz # schedule baz directory for deletion
$ touch newfile
$ svn add newfile # schedule newfile for addition
That's a lot of changes! If we were to leave and come
back tomorrow, how could we remember what changes we'd made?
Easy. The status command will show us all
local modifications in our working
$ svn status # See what's locally modified
According to this output, three items are scheduled to be
(D)eleted from the repository, one item is scheduled to be
(A)dded to the repository, and two items have had their
contents (M)odified in some way. For more details, be sure to
read about svn status in Chapter 3 of the
Now we decide to commit our changes, creating Revision 2
in the repository:
$ svn commit -m "fixed bug #233"
Committed revision 2.
The -m argument is a way of specifying a log
message: that is, a specific description of your
change-set sent to the repository. The log message is now
attached to Revision 2. A future user might peruse repository
log messages, and now will know what your Revision 2 changes
Finally, pretend that you are now Felix, or some other
collaborator. If you go wc2 (that other working
copy you made), it will need the svn update
command to receive the Revision 2 changes:
$ cd ../wc2 # change to the back-up working copy
$ svn update # get changes from repository
The output of the svn update command
tells Felix that baz was (D)eleted from his working copy,
newfile was (A)dded to his working copy, and that bar and foo
had their contents (U)pdated.
If for some reason bar contained some local
changes made by Felix, then the server changes would be
merged into bar: that is,
bar would now contain both sets of changes.
Whenever server changes are merged into a locally-modified
file, two possible things can happen:
The merge can go smoothly. That is, the two sets of
changes do not overlap. In this case, svn
update prints a G
The sets of changes overlap, and a
C for (C)onflict is printed. See
section ??? for information about how conflict resolution