当对远程源版本库使用svnsync时，使用Subversion的自定义网络协议。
svnserve允许Subversion版本库使用svn网络协议，你可以作为独立服务器进程运行svnserve，或者是使用其它进程，如inetd,
xinetd(也是svn://)或使用svn+ssh://访问方法的sshd为你启动进程。
Regardless of the access method, once the client has selected a repository
by transmitting its URL, svnserve reads a file named
conf/svnserve.conf in the repository directory to
determine repository-specific settings such as what authentication database
to use and what authorization policies to apply. See 第 3 节 “svnserve - 定制的服务器 ” for details of the
svnserve.conf file.
Unlike the previous commands we've described, svnserve has no subcommands—it is controlled exclusively by options.
--daemon (-d)
Causes svnserve to run in daemon mode.
svnserve backgrounds itself and accepts and serves TCP/IP
connections on the svn port (3690, by default).
--foreground
When used together with -d, causes
svnserve to stay in the foreground. This is mainly
useful for debugging.
--inetd (-i)
导致 svnserve 使用 stdin 和
stdout 文件描述符，适用于 inetd 守护进程。
--help (-h)
显示有用的摘要和选项。
--listen-host HOST
svnserve监听的HOST，可能是一个主机名或是一个IP地址。
--listen-once (-X)
Causes svnserve to accept one connection on the
svn port, serve it, and exit. This option is mainly
useful for debugging.
--listen-port PORT
Causes svnserve to listen on
PORT when run in daemon mode. (FreeBSD daemons
listen only on tcp6 by default—this option tells them to also listen
on tcp4.)
--log-file FILENAME
Instructs svnserve to create (if necessary) and use the
file located at FILENAME for Subversion
operational log output of the same sort that mod_dav_svn
generates. See 第 6 节 “High-level Logging” for
details.
--pid-file FILENAME
Causes svnserve to write its process ID to
FILENAME, which must be writable by the user
under which svnserve is running.
--root (-r)
ROOT
Sets the virtual root for repositories served by svnserve. The pathname in URLs provided by the client will be interpreted relative to this root and will not be allowed to escape this root.
--threads (-T)
When running in daemon mode, causes svnserve to spawn a thread instead of a process for each connection (e.g., for when running on Windows). The svnserve process still backgrounds itself at startup time.
--tunnel (-t)
Causes svnserve to run in tunnel mode, which is just like
the inetd mode of operation (both modes serve one
connection over stdin/stdout, and
then exit), except that the connection is considered to be preauthenticated
with the username of the current UID. This flag is automatically passed for
you by the client when running over a tunnel agent such as
ssh. That means there's rarely any need for
you to pass this option to
svnserve. So, if you find yourself typing
svnserve --tunnel on the command line and wondering what
to do next, see 第 3.4 节 “穿越 SSH 隧道”.
--tunnel-user NAME
Used in conjunction with the --tunnel option, tells
svnserve to assume that NAME
is the authenticated user, rather than the UID of the
svnserve process. This is useful for users wishing to
share a single system account over SSH, but to maintain separate commit
identities.
--version
显示版本信息，版本库后端存在和可用的模块列表，然后退出。