Most of the time, you will start using a Subversion
repository by doing a checkout of your
project. Checking out a repository creates a “working
copy” of it on your local machine. This copy contains
HEAD (latest revision) of the Subversion
repository that you specify on the command line:
$ svn checkout http://svn.collab.net/repos/svn/trunk A trunk/Makefile.in A trunk/ac-helpers A trunk/ac-helpers/install.sh A trunk/ac-helpers/install-sh A trunk/build.conf … Checked out revision 8810.
Although the above example checks out the trunk directory, you can just as easily check out any deep subdirectory of a repository by specifying the subdirectory in the checkout URL:
$ svn checkout -r 8810 \ http://svn.collab.net/repos/svn/trunk/subversion/tests/cmdline/ A cmdline/revert_tests.py A cmdline/diff_tests.py A cmdline/autoprop_tests.py A cmdline/xmltests A cmdline/xmltests/svn-test.sh … Checked out revision 8810.
Since Subversion uses a “copy-modify-merge” model instead of “lock-modify-unlock” (see the section called “Versioning Models”), you're already able to start making changes to the files and directories in your working copy. Your working copy is just like any other collection of files and directories on your system. You can edit and change them, move them around, you can even delete the entire working copy and forget about it.
While your working copy is “just like any other collection of files and directories on your system”, you can edit files at will, but you must tell Subversion about everything elsethat you do. For example, if you want to copy or move an item in a working copy, you should use svn copy or svn move instead of the copy and move commands provided by your operating system. We'll talk more about them later in this chapter.
Unless you're ready to commit a new file or directory, or changes to existing ones, there's no need to further notify the Subversion server that you've done anything.
While you can certainly check out a working copy with the URL of the repository as the only argument, you can also specify a directory after your repository URL. This places your working copy in the new directory that you name. For example:
$ svn -r 8810 checkout http://svn.collab.net/repos/svn/trunk subv A subv/Makefile.in A subv/ac-helpers A subv/ac-helpers/install.sh A subv/ac-helpers/install-sh A subv/build.conf … Checked out revision 8810.
That will place your working copy in a directory named
subv instead of a directory named
trunk as we did previously. The directory
subv will be created if it doesn't already
When you perform a Subversion operation that requires you to authenticate, by default Subversion caches your authentication credentials on disk. If you're concerned about caching your Subversion passwords, you can disable caching either permanently or on a case-by-case basis.
To disable password caching for a particular one-time
command, pass the
--no-auth-cache switch on
the commandline. To permanently disable caching, you can add
store-passwords = no to your local
machine's Subversion configuration file. See the section called “Client Credentials Caching” for
Since Subversion caches auth credentials by default (both
username and password), it conveniently remembers who you were
acting as the last time you modified you working copy. But
sometimes that's not helpful—particularly if you're
working in a shared working copy, like a system configuration
directory or a webserver document root. In this case, just
--username option on the
commandline and Subversion will attempt to authenticate as
that user, prompting you for a password if necessary.
 Of course, you're not terribly worried—first because you know that you can't really delete anything from Subversion and, secondly, because your Subversion password isn't the same as any of the other three million passwords you have, right? Right?