Pipes (and sockets and FIFOs) aren't seekable on most *NIX flavours I believe, so you're going to have to do your own buffering of some form. The less pager for instance spools piped input to a temporary file and then seeks on that. You could do something similar, or if you really only need one line just write your own one-line-buffering wrapper and use that to read rather than using your pipe filehandle directly.