Hi Shiva,
Oh, I see now. My mistake in reading the requirements!
I take this "same script should run by logging into B server" to mean that you do have some sort of log-in to the B server? That you have a user account?

If you do have a shell account on B, then I would do things a bit differently. Walking through the process as a person... Imagine that you are at another computer D. You use D to manually log-in to B. So you are now at the command prompt on the B machine. Then you issue the shell commands that cause B to get the file from A. Then you issue the commands to cause B to put the file to C. Well, if a person can do this, then a Perl program can do it too! You do not need independent machine D, this can be just A. In other words, you write a program that simulates a human doing these manual steps and run that program on A. This requires a login to B. Would that scenario work?

There are other ways if you can run a Perl program on B that "helps out" the program that you run on A. I just want to verify that it is not allowed to have any code at all running on B?

Update: The bottom line question: Do you have any way at all of causing this file to be moved as described without a Perl program? We can automate what is already possible. We cannot make possible what is simply impossible.