How to auto login ssh server and run some command to modify a file

Question

Here is the limitations:

1. No public key file uploaded to server (since this may be run at different target machine), this is just for an automatic testing program, so security is not a concern.
2. It's automatically program run background, so no user input.
3. I do not want to use "expect" which require user to install.
4. I have know the root user's password.

So I wonder is that a lightweight expect tool or a ssh library I can easily use to do such work.

Answer 1

libssh http://www.libssh.org/ can help for a C project. Using Perl, there is a module which can be used: Net::SSH (I use it for +/- the same kind of purposes)

Answer 2

唯一正确的安全方法是使用导出的SSH公钥文件，每个客户端和每台服务器均已通过验证，否则，阻止哈巴巴迪先生利用该系统的措施是什么？