Secure CVS from a UNIX machine using SSH

Configuration.
The following software packages must be installed and available from your UNIX account:
CVS/cvs         UNIX CVS client
SSH/ssh         UNIX SSH client

Summary：
CVS:            CVS is a UNIX program that allows to connect to a local or
        remote CVS server/repository.  Using CVS, it is possible
        to copy any items that need editing, - programming code,
        HTML pages, sensitive system configuration files, - to
        directory in your UNIX account, work with them locally,
        and upload them to the CVS server once you are done.

SSH:            SSH is a terminal program that encrypts the communication
        between your machine and the server, thereby making any
        data, including usernames and passwords, invisible to
        potential attackers.

配置：
第一步：Make sure that both CVS and SSH are installed and available from your UNIX account.
        Use the following command to verify that both packages are available:
        which PACKAGE
        where PACKAGE is 'cvs' or 'ssh'. If the command returns an error, contact your system administrator.
    #ssh-keygen -t dsa
    生成的id_dsa.pub ，拷贝到cvs服务器端,相同账号.ssh目录下，执行cat id_dsa.pub>>authorized_keys2

第二步：Tell CVS to use SSH to communicate with the server:
    setenv CVS_RSH ssh (when your shell is csh/tcsh)
or
    export CVS_RSH=ssh (when your shell is bash)
    
    #vi ~/.bash_profile
    export CVS_RSH=ssh
    export CVSROOT=/usr/local/cvsroot
    #source ~/.bash_file
    
第三步:Now you can perform any CVS operations, such as checking out files, committing changes, etc.
        cvs -d :ext:[e-mail]:/cvsroot CVS_COMMAND

例如：
#cd /usr/local/cvsroot 到CVSROOT目录下，执行命令
#cvs -z3  -d :ext:账号@CVS服务器:cvs服务器端项目的目录  checkout  模块