The most obvious design wart to me is this: If you want to establish bi-directional communication with some process on the same host, that process should creat

The most obvious design wart to me is this: If you want to establish bi-directional communication with some process on the same host, that process should create two rendezvous points with mkfifo(2). Your process opens the read FIFO for reading, and the write FIFO for writing, and you're done. If you finish writing and want to just read, you close(2) the write file descriptor, and keep reading the read file-descriptor until you hit EOF. If you want to establish bi-directional communication with some process on a remote host over TCP/IP, that process needs to listen(2). Your process connects to it with connect(2), and gets back a single-file descriptor that (unlike any other file-descriptor) is both writable and readable. If you finish writing and want to just read, you have to use the special shutdown(2) function, a quirk that only exist to work around the quirk of TCP sockets being both readable and writable. Some might argue that this is a pretty minor wart, all things considered, and sure, it's nowhere near as confusing as the mess of terminal job control. But it also seems like it they could have implemented it in a non-quirky way if they'd just spent thirty seconds thinking about it beforehand.