[R] how to know if a file exists on a remote server?

[Baoqiang Cao]

Hi,

I'd like to download some data files from a remote server, the problem
here is that some of the files actually don't exist, which I don't
know before try. Just wondering if a function in R could tell me if a
file exists on a remote server? I searched this mailing list and after
read severals mails, still clueless.  Any help will be highly
appreciated.

B.C.