> Looking back, it's unfortunate that Unix authors offered piping of input and output streams, but did not extend that to arbitrary number of streams They did

> Looking back, it's unfortunate that Unix authors offered piping of input and output streams, but did not extend that to arbitrary number of streams They did though - file handles are inherited by child processes which allows you to pass one end of a pipe and then feed things into the other end. E.g. make uses this to communicate between recursive invocations for concurrency control.