Linux系统中缺省安装了SVN。使用rpm -e卸载后执行svn命令行操作就会出现标题中的错误。

# svn --version
svn, version 1.4.6 (r28521)
   compiled Feb 23 2016, 10:04:35

Copyright (C) 2000-2007 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_svn : Module for accessing a repository using the svn network protocol.
  - handles 'svn' scheme
* ra_local : Module for accessing a repository on local disk.
  - handles 'file' scheme

原因应该是卸载SVN时同时卸载了ra_dav模块。需要安装neon，neon 是HTTP和WebDAV客户端的库，是用来作为Subversion服务器和HTTP客户端进行通讯的库。主要负责http的基本操作和授权操作。下载地址：http://www.webdav.org/neon/

我下载的是neon-0.26.4.tar.gz，使用下面命令解压就好，记住不是“tar zxvf"

# tar xvf neon-0.26.4.tar.gz

# ./configure  --prefix=/usr/local/neon --with-ssl=openssl --enable-shared  (一定要加--enable-shared 参数）

# make && make install

然后重新安装SVN

[root@huadi-160219095359 subversion-1.4.6]# ./configure --prefix=/usr/local/svn --with-apxs=/usr/local/apache/bin/apxs --with-apr=/usr/local/apache/bin/apr-1-config --with-apr-util=/usr/local/apache/bin/apu-1-config  --with-neon=/usr/local/neon

# make && make install

安装完成后，Unrecognized URL scheme错误就消失了。

[root@huadi-160219095359 ~]# svn --version
svn, version 1.6.12 (r955767)
   compiled Mar 30 2016, 17:07:24

Copyright (C) 2000-2009 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_neon : Module for accessing a repository via WebDAV protocol using Neon.
  - handles 'http' scheme
  - handles 'https' scheme
* ra_svn : Module for accessing a repository using the svn network protocol.
  - with Cyrus SASL authentication
  - handles 'svn' scheme
* ra_local : Module for accessing a repository on local disk.
  - handles 'file' scheme
* ra_serf : Module for accessing a repository via WebDAV protocol using serf.
  - handles 'http' scheme
  - handles 'https' scheme

卸载软件：

#make uninstall  (删掉make install命令时安装的文件）

#make clean  （只删掉make时产生的临时文件）

#make distclean （删掉configure和make产生的临时文件）