"Modtime, you have no idea if the remote file is rebuild periodically"
Neither do you.
"Why you'd want to get a "sense" of file changes is beyond me when the only logical way is to compare the file contents. Not their size, or their modification date."
Because if nothing's changed. No reason to go further.
""Be bothered to be required"? why would they read perltoot or perlootut to ask a question about FTP?"
You missed the context, and therefore, the point. It'd be totally lost, and impossible to re-atain, right here.
You're just being pedantic. I endevoured to begin a path to a possible solution. While attempting to expand on my initial post. I found myself having to justify my comment(s) to you, rather than broaden the possibilities (maybe with ftp) for a potential solution to the OP's question. I find this regretable, and ultimately, degradation of a possibly valuable thread. In the end, I greatly squandered efforts, and energy I had intended to spend on providing a possible solution to the OP's question. Rebuttal of this nature, I think is better spent in the CB, leaving the thread for the final outcome of the rebuttal, not the rebuttal itself.