This assumes the stream would be line oriented. Of course that should be true for most circumstances (he even mentions tail -f). But if it is not things get a bit more tricky and he would need to read character by character by some low level system call.
Comment on Re: Re: reading output from another script
Well, yeah, and things could even be more tricky if the
read in characters are in some strange encoding, and an
obscure language. ;-)
I read the article from the OP as if (s)he had problems
with the fact that the source (s)he's reading from
continues to produce data - not that (s)he needed help
with non line oriented input. But even if you want to
read byte by byte, just do a S/ = \1 before reading.