Subversion provides many optional behaviors that the user can control. Many of these options are of the kind that a user would wish to apply to all Subversion operations. So, rather than forcing users to remember command-line arguments for specifying these options and to use them for every operation they perform, Subversion uses configuration files, segregated into a Subversion configuration area.
The Subversion configuration area is a two-tiered hierarchy of option names and their values. Usually, this boils down to a special directory that contains configuration files (the first tier), which are just text files in standard INI format where “sections” provide the second tier. You can easily edit these files using your favorite text editor (such as Emacs or vi), and they contain directives read by the client to determine which of several optional behaviors the user prefers.
The first time the svn command-line
        client is executed, it creates a per-user configuration area.
        On Unix-like systems, this area appears as a directory
        named .subversion in the user's home
        directory.  On Win32 systems, Subversion creates a folder
        named Subversion, typically inside
        the Application Data area of the user's
        profile directory (which, by the way, is usually a hidden
        directory).  However, on this platform, the exact location
        differs from system to system and is dictated by the Windows
        Registry.[61]
        We will refer to the per-user configuration area using its
        Unix name, .subversion.
In addition to the per-user configuration area, Subversion
        also recognizes the existence of a system-wide configuration
        area.  This gives system administrators the ability to
        establish defaults for all users on a given machine.  Note
        that the system-wide configuration area alone does not dictate
        mandatory policy—the settings in the per-user
        configuration area override those in the system-wide one, and
        command-line arguments supplied to the svn
        program have the final word on behavior.  On Unix-like
        platforms, the system-wide configuration area is
        expected to be the /etc/subversion
        directory; on Windows machines, it looks for a
        Subversion directory inside the common
        Application Data location (again, as
        specified by the Windows Registry).  Unlike the per-user
        case, the svn program does not attempt
        to create the system-wide configuration area.
The per-user configuration area currently contains three
        files—two configuration files (config and
        servers), and a README.txt 
        file, which describes the INI format.  At the time of their
        creation, the files contain default values for each of the
        supported Subversion options, mostly commented out and grouped
        with textual descriptions about how the values for the key
        affect Subversion's behavior.  To change a certain behavior,
        you need only to load the appropriate configuration file into
        a text editor, and to modify the desired option's value.  If at
        any time you wish to have the default configuration settings
        restored, you can simply remove (or rename) your configuration
        directory and then run some innocuous svn
        command, such as svn --version.  A new
        configuration directory with the default contents will be
        created.
Subversion also allows you to override individual
        configuration option values at the command line via
        the --config-option option, which is
        especially useful if you need to make a (very) temporary
        change in behavior.  For more about this option's proper
        usage, see the section called “svn Options”.
The per-user configuration area also contains a cache of
        authentication data.  The auth directory
        holds a set of subdirectories that contain pieces of cached
        information used by Subversion's various supported
        authentication methods.  This directory is created in such a
        way that only the user herself has permission to read its
        contents.
In addition to the usual INI-based configuration area, Subversion clients running on Windows platforms may also use the Windows Registry to hold the configuration data. The option names and their values are the same as in the INI files. The “file/section” hierarchy is preserved as well, though addressed in a slightly different fashion—in this schema, files and sections are just levels in the Registry key tree.
Subversion looks for system-wide configuration values
        under the
        HKEY_LOCAL_MACHINE\Software\Tigris.org\Subversion
        key.  For example, the global-ignores option,
        which is in the miscellany section of the
        config file, would be found at
        HKEY_LOCAL_MACHINE\Software\Tigris.org\Subversion\Config\Miscellany\global-ignores.
        Per-user configuration values should be stored under
        HKEY_CURRENT_USER\Software\Tigris.org\Subversion.
Registry-based configuration options are parsed before their file-based counterparts, so they are overridden by values found in the configuration files. In other words, Subversion looks for configuration information in the following locations on a Windows system; lower-numbered locations take precedence over higher-numbered locations:
Command-line options
The per-user INI files
The per-user Registry values
The system-wide INI files
The system-wide Registry values
Also, the Windows Registry doesn't really support the
        notion of something being “commented out.”
        However, Subversion will ignore any option key whose name
        begins with a hash (#) character.  This
        allows you to effectively comment out a Subversion option
        without deleting the entire key from the Registry, obviously
        simplifying the process of restoring that option.
The svn command-line client never
        attempts to write to the Windows Registry and will not attempt
        to create a default configuration area there.  You can create
        the keys you need using the REGEDIT
        program.  Alternatively, you can create a
        .reg file (such as the one in Example 7.1, “Sample registration entries (.reg) file”), and
        then double-click on that file's icon in the Explorer shell,
        which will cause the data to be merged into your
        Registry.
Example 7.1. Sample registration entries (.reg) file
REGEDIT4 [HKEY_LOCAL_MACHINE\Software\Tigris.org\Subversion\Servers\groups] [HKEY_LOCAL_MACHINE\Software\Tigris.org\Subversion\Servers\global] "#http-auth-types"="basic;digest;negotiate" "#http-compression"="yes" "#http-library"="" "#http-proxy-exceptions"="" "#http-proxy-host"="" "#http-proxy-password"="" "#http-proxy-port"="" "#http-proxy-username"="" "#http-timeout"="0" "#neon-debug-mask"="" "#ssl-authority-files"="" "#ssl-client-cert-file"="" "#ssl-client-cert-password"="" "#ssl-pkcs11-provider"="" "#ssl-trust-default-ca"="" "#store-auth-creds"="yes" "#store-passwords"="yes" "#store-plaintext-passwords"="ask" "#store-ssl-client-cert-pp"="yes" "#store-ssl-client-cert-pp-plaintext"="ask" "#username"="" [HKEY_CURRENT_USER\Software\Tigris.org\Subversion\Config\auth] "#password-stores"="windows-cryptoapi" [HKEY_CURRENT_USER\Software\Tigris.org\Subversion\Config\helpers] "#diff-cmd"="" "#diff-extensions"="-u" "#diff3-cmd"="" "#diff3-has-program-arg"="" "#editor-cmd"="notepad" "#merge-tool-cmd"="" [HKEY_CURRENT_USER\Software\Tigris.org\Subversion\Config\tunnels] [HKEY_CURRENT_USER\Software\Tigris.org\Subversion\Config\miscellany] "#enable-auto-props"="no" "#global-ignores"="*.o *.lo *.la *.al .libs *.so *.so.[0-9]* *.a *.pyc *.pyo *.rej *~ #*# .#* .*.swp .DS_Store" "#interactive-conflicts"="yes" "#log-encoding"="" "#mime-types-file"="" "#no-unlock"="no" "#preserved-conflict-file-exts"="doc ppt xls od?" "#use-commit-times"="no" [HKEY_CURRENT_USER\Software\Tigris.org\Subversion\Config\auto-props]
Example 7.1, “Sample registration entries (.reg) file”
        shows the contents of a .reg file, which
        contains some of the most commonly used configuration options
        and their default values.  Note the presence of both
        system-wide (for network proxy-related options) and per-user
        settings (editor programs and password storage, among others).
        Also note that all the options are effectively commented out.
        You need only to remove the hash (#)
        character from the beginning of the option names and set the
        values as you desire.
In this section, we will discuss the specific runtime configuration options that Subversion currently supports.
The servers file contains
          Subversion configuration options related to the network
          layers.  There are two special sections in this
          file—[groups] and
          [global].  The [groups]
          section is essentially a cross-reference table.  The keys in
          this section are the names of other sections in the file;
          their values are globs—textual
          tokens that possibly contain wildcard
          characters—that are compared against the hostnames of
          the machine to which Subversion requests are sent.
[groups] beanie-babies = *.red-bean.com collabnet = svn.collab.net [beanie-babies] … [collabnet] …
When Subversion is used over a network, it attempts to
          match the name of the server it is trying to reach with a
          group name under the [groups] section.  If
          a match is made, Subversion then looks for a section in the
          servers file whose name is the matched
          group's name.  From that section, it reads the actual network
          configuration settings.
The [global] section contains the
          settings that are meant for all of the servers not matched
          by one of the globs under the [groups]
          section.  The options available in this section are
          exactly the same as those that are valid for the other server
          sections in the file (except, of course, the special
          [groups] section), and are as
          follows:
http-auth-types
                
              This is a semicolon-delimited list of HTTP
                authentication types which the client will deem
                acceptable.  Valid types
                are basic, digest,
                and negotiate, with the default
                behavior being acceptance of any these authentication
                types.  A client which insists on not transmitting
                authentication credentials in cleartext might, for
                example, be configured such that the value of this
                option is
                digest;negotiate—omitting
                basic from the list.  (Note that
                this setting is only honored by Subversion's
                Neon-based HTTP provider module.)
http-compression
                
              This specifies whether Subversion should
                attempt to compress network requests made to DAV-ready
                servers.  The default value is yes
                (though compression will occur only if that capability
                is compiled into the network layer).  Set this to
                no to disable compression, such as
                when debugging network transmissions.
http-library
                
              Subversion provides a pair of repository access
                modules that understand its WebDAV network protocol.
                The original one, which shipped with Subversion 1.0, is
                libsvn_ra_neon (though back then it
                was called libsvn_ra_dav).  Newer
                Subversion versions also provide
                libsvn_ra_serf, which uses a
                different underlying implementation and aims to
                support some of the newer HTTP concepts.
At this point, libsvn_ra_serf
                is still considered experimental, though it appears to
                work in the common cases quite well.  To encourage
                experimentation, Subversion provides the
                http-library runtime configuration
                option to allow users to specify (generally, or in a
                per-server-group fashion) which WebDAV access module
                they'd prefer to use—neon or
                serf.
http-proxy-exceptions
                
              This specifies a comma-separated list of patterns for repository hostnames that should be accessed directly, without using the proxy machine. The pattern syntax is the same as is used in the Unix shell for filenames. A repository hostname matching any of these patterns will not be proxied.
http-proxy-host
                
              This specifies the hostname of the proxy computer through which your HTTP-based Subversion requests must pass. It defaults to an empty value, which means that Subversion will not attempt to route HTTP requests through a proxy computer, and will instead attempt to contact the destination machine directly.
http-proxy-password
                
              This specifies the password to supply to the proxy machine. It defaults to an empty value.
http-proxy-port
                
              This specifies the port number on the proxy host to use. It defaults to an empty value.
http-proxy-username
                
              This specifies the username to supply to the proxy machine. It defaults to an empty value.
http-timeout
                
              This specifies the amount of time, in seconds, to
                wait for a server response.  If you experience
                problems with a slow network connection causing
                Subversion operations to time out, you should increase
                the value of this option.  The default value is
                0, which instructs the underlying
                HTTP library, Neon, to use its default timeout
                setting.
neon-debug-mask
                
              This is an integer mask that the underlying HTTP
                library, Neon, uses for choosing what type of
                debugging output to yield.  The default value is
                0, which will silence all debugging
                output.  For more information about how Subversion
                makes use of Neon, see Chapter 8, Embedding Subversion.
ssl-authority-files
                
              This is a semicolon-delimited list of paths to files containing certificates of the certificate authorities (or CAs) that are accepted by the Subversion client when accessing the repository over HTTPS.
ssl-client-cert-file
                
              If a host (or set of hosts) requires an SSL client certificate, you'll normally be prompted for a path to your certificate. By setting this variable to that same path, Subversion will be able to find your client certificate automatically without prompting you. There's no standard place to store your certificate on disk; Subversion will grab it from any path you specify.
ssl-client-cert-password
                
              If your SSL client certificate file is encrypted
                by a passphrase, Subversion will prompt you for the
                passphrase whenever the certificate is used.  If you
                find this annoying (and don't mind storing the
                password in the servers file),
                you can set this variable to the certificate's
                passphrase.  You won't be prompted anymore.
ssl-pkcs11-provider
                
              The value of this option is the name of the PKCS#11 provider from which an SSL client certificate will be drawn (if the server asks for one). This setting is only honored by Subversion's Neon-based HTTP provider module.
ssl-trust-default-ca
                
              Set this variable to yes if you
                want Subversion to automatically trust the set of
                default CAs that ship with OpenSSL.
store-auth-creds
                
              This setting is the same as
                store-passwords, except that it
                enables or disables on-disk caching of
                all authentication information:
                usernames, passwords, server certificates, and any
                other types of cacheable credentials.
store-passwords
                
              This instructs Subversion to cache, or not to
                cache, passwords that are supplied by the user in
                response to server authentication challenges.  The
                default value is yes.  Set this to
                no to disable this on-disk password
                caching.  You can override this option for a single
                instance of the svn command using
                the --no-auth-cache command-line
                parameter (for those subcommands that support it).
                For more information regarding that, see
                the section called “Caching credentials”.
                Note that regardless of how this option is configured,
                Subversion will not store passwords in plaintext
                unless the store-plaintext-passwords
                option is also set to yes.
store-plaintext-passwords
                
              This variable is only important on UNIX-like systems.
                It controls what the Subversion client does in case
                the password for the current authentication realm can
                only be cached on disk in unencrypted form, in the
                ~/.subversion/auth/ caching area.
                You can set it to yes or
                no to enable or disable caching of
                passwords in unencrypted form, respectively.
                The default setting is ask, which causes
                the Subversion client to ask you each time a
                new password is about to be added to
                the ~/.subversion/auth/ caching area.
store-ssl-client-cert-pp
                
              This option controls whether Subversion will cache
                SSL client certificate passphrases provided by the
                user.  Its value defaults to yes.
                Set this to no to disable this
                passphrase caching.
store-ssl-client-cert-pp-plaintext
                
              This option controls whether Subversion, when
                attempting to cache an SSL client certificate
                passphrase, will be allowed to do so using its on-disk
                plaintext storage mechanism.  The default value of
                this option is ask, which causes
                the Subversion client to ask you each time a
                new client certificate passphrase
                is about to be added to
                the ~/.subversion/auth/ caching
                area.  Set this option's value
                to yes or no to
                indicate your preference and avoid related
                prompts.
The config file contains the rest
          of the currently available Subversion runtime
          options—those not related to networking.  There are
          only a few options in use as of this writing, but they are
          again grouped into sections in expectation of future
          additions.
The [auth] section contains settings
          related to Subversion's authentication and authorization
          against the repository.  It contains the following:
password-stores
                
              This comma-delimited list specifies which (if any)
                system-provided password stores Subversion should
                attempt to use when saving and retrieving cached
                authentication credentials, and in what order
                Subversion should prefer them.  The default value is
                gnome-keyring, kwallet, keychain,
                windows-crypto-api, representing the GNOME
                Keyring, KDE Wallet, Mac OS X Keychain, and Microsoft
                Windows cryptography API, respectively.  Listed stores
                which are not available on the system are
                ignored.
store-passwords
                
              This option has been deprecated from
                the config file.  It now lives as
                a per-server configuration item in
                the servers configuration area.
                See the section called “Servers”
                for details.
store-auth-creds
                
              This option has been deprecated from
                the config file.  It now lives as
                a per-server configuration item in
                the servers configuration area.
                See the section called “Servers”
                for details.
The [helpers] section controls which
          external applications Subversion uses to accomplish its
          tasks.  Valid options in this section are:
diff-cmd
                
              This specifies the absolute path of a differencing program, used when Subversion generates “diff” output (such as when using the svn diff command). By default, Subversion uses an internal differencing library—setting this option will cause it to perform this task using an external program. See the section called “Using External Differencing and Merge Tools” for more details on using such programs.
diff-extensions
                
              Like the --extensions
                (-x) command-line option, this
                specifies additional options passed to the file
                content differencing engine.  The set of meaningful
                extension options differs depending on whether the
                client is using Subversion's internal differencing
                engine or an external mechanism.  See the output
                of svn help diff for details.
                The default value for this option
                is -u.
diff3-cmd
                
              This specifies the absolute path of a three-way differencing program. Subversion uses this program to merge changes made by the user with those received from the repository. By default, Subversion uses an internal differencing library—setting this option will cause it to perform this task using an external program. See the section called “Using External Differencing and Merge Tools” for more details on using such programs.
diff3-has-program-arg
                
              This flag should be set to true
                if the program specified by the
                diff3-cmd option accepts a
                --diff-program command-line
                parameter.
editor-cmd
                
              This specifies the program Subversion will use to query the user for certain types of textual metadata or when interactively resolving conflicts. See the section called “Using External Editors” for more details on using external text editors with Subversion.
merge-tool-cmd
                
              This specifies the program that Subversion will use to perform three-way merge operations on your versioned files. See the section called “Using External Differencing and Merge Tools” for more details on using such programs.
The [tunnels] section allows you to
          define new tunnel schemes for use with
          svnserve and svn://
          client connections.  For more details, see the section called “Tunneling over SSH”.
The miscellany section is where
          everything that doesn't belong elsewhere winds
          up.[62]  In this section, you can
          find:
enable-auto-props
                
              This instructs Subversion to automatically set
                properties on newly added or imported files.  The
                default value is no, so set this to
                yes to enable this feature.
                The [auto-props] section of this file
                specifies which properties are to be set on which files.
global-ignores
                
              When running the svn status
                command, Subversion lists unversioned files and
                directories along with the versioned ones, annotating
                them with a ? character (see the section called “See an overview of your changes”).  Sometimes it can
                be annoying to see uninteresting, unversioned
                items—for example, object files that result from
                a program's compilation—in this display.  The
                global-ignores option is a list of
                whitespace-delimited globs that describe the names of
                files and directories that Subversion should not
                display unless they are versioned.  The default value
                is *.o *.lo *.la *.al .libs *.so *.so.[0-9]*
                *.a *.pyc *.pyo *.rej *~ #*# .#* .*.swp
                .DS_Store.
As well as svn status, the
                svn add and svn import
                commands also ignore files that match the list
                when they are scanning a directory.  You can override this
                behavior for a single instance of any of these commands
                by explicitly specifying the filename, or by using
                the --no-ignore command-line flag.
For information on finer-grained control of ignored items, see the section called “Ignoring Unversioned Items”.
interactive-conflicts
                
              This is a Boolean option that specifies whether
                Subversion should try to resolve conflicts
                interactively.  If its value is yes
                (which is the default value), Subversion will prompt
                the user for how to handle conflicts in the manner
                demonstrated in the section called “Resolve Any Conflicts”.  Otherwise, it will simply flag the conflict and
                continue its operation, postponing resolution to a later
                time.
log-encoding
                
              This variable sets the default character set
                encoding for commit log messages.  It's a permanent
                form of the --encoding option (see
                the section called “svn Options”).  The Subversion
                repository stores log messages in UTF-8 and assumes
                that your log message is written using your operating
                system's native locale.  You should specify a
                different encoding if your commit messages are written
                in any other encoding.
mime-types-file
                
              This option, new to Subversion 1.5, specifies the
                path of a MIME types mapping file, such as the
                mime.types file provided by the
                Apache HTTP Server.  Subversion uses this file to
                assign MIME types to newly added or imported files.
                See the section called “Automatic Property Setting” and
                the section called “File Content Type” for more about Subversion's detection and use of
                file content types.
no-unlock
                
              This Boolean option corresponds to svn
                commit's --no-unlock
                option, which tells Subversion not to release locks on
                files you've just committed.  If this runtime option
                is set to yes, Subversion will
                never release locks automatically, leaving you to run
                svn unlock explicitly.  It defaults
                to no.
preserved-conflict-file-exts
                
              The value of this option is a space-delimited list of file extensions that Subversion should preserve when generating conflict filenames. By default, the list is empty. This option is new to Subversion 1.5.
When Subversion detects conflicting file content
                changes, it defers resolution of those conflicts to the
                user.  To assist in the resolution, Subversion keeps
                pristine copies of the various competing versions of
                the file in the working copy.  By default, those
                conflict files have names constructed by appending to
                the original filename a custom extension such as
                .mine or
                .
                (where REVREV is a revision
                number).  A mild annoyance with this naming scheme is
                that on operating systems where a file's extension
                determines the default application used to open and
                edit that file, appending a custom extension prevents
                the file from being easily opened by its native
                application.  For example, if the file
                ReleaseNotes.pdf was conflicted,
                the conflict files might be named
                ReleaseNotes.pdf.mine or
                ReleaseNotes.pdf.r4231.  While
                your system might be configured to use Adobe's Acrobat
                Reader to open files whose extensions are
                .pdf, there probably isn't an
                application configured on your system to open all
                files whose extensions are
                .r4231.
You can fix this annoyance by using this
                configuration option, though.  For files with one of
                the specified extensions, Subversion will append to
                the conflict file names the custom extension just as
                before, but then also reappend the file's original
                extension.  Using the previous example, and assuming
                that pdf is one of the extensions
                configured in this list thereof, the conflict files
                generated for ReleaseNotes.pdf
                would instead be named
                ReleaseNotes.pdf.mine.pdf and
                ReleaseNotes.pdf.r4231.pdf.
                Because each file ends in
                .pdf, the correct default
                application will be used to view them.
use-commit-times
                
              Normally your working copy files have timestamps that reflect the last time they were touched by any process, whether your own editor or some svn subcommand. This is generally convenient for people developing software, because build systems often look at timestamps as a way of deciding which files need to be recompiled.
In other situations, however, it's sometimes nice
                for the working copy files to have timestamps that
                reflect the last time they were changed in the
                repository.  The svn export command
                always places these “last-commit
                timestamps” on trees that it produces.  By
                setting this config variable to
                yes, the svn
                checkout, svn update,
                svn switch, and svn
                revert commands will also set last-commit
                timestamps on files that they touch.
The [auto-props] section controls the
          Subversion client's ability to automatically set properties
          on files when they are added or imported.  It contains any
          number of key-value pairs in the
          format PATTERN
          = PROPNAME=VALUE[;PROPNAME=VALUE
          ...]PATTERN is
          a file pattern that matches one or more filenames and the
          rest of the line is a semicolon-delimited set of property
          assignments.  (If you need to use a semicolon in your
          property's name or value, you can escape it by doubling
          it.)
$ cat ~/.subversion/config … [auto-props] *.c = svn:eol-style=native *.html = svn:eol-style=native;svn:mime-type=text/html;; charset=UTF8 *.sh = svn:eol-style=native;svn:executable … $ cd projects/myproject $ svn status ? www/index.html $ svn add www/index.html A www/index.html $ svn diff www/index.html … Property changes on: www/index.html ___________________________________________________________________ Added: svn:mime-type ## -0,0 +1 ## +text/html; charset=UTF8 Added: svn:eol-style ## -0,0 +1 ## +native $
Multiple matches on a file will result in
          multiple propsets for that file; however, there is no
          guarantee that auto-props will be applied in the order in
          which they are listed in the config file, so you can't have
          one rule “override” another.  You can find
          several examples of auto-props usage in the
          config file.  Lastly, don't
          forget to set enable-auto-props to
          yes in the miscellany
          section if you want to enable auto-props.