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Above is pretty much pseudo code of how I implemented my piping. First off, is this idea correct?
Secondly, and I am very confused on this point, is how I'm supposed to treat each program before the last one (ls and grep before sed). The way I implemented the multi-piping is by NOT waiting for anything except the last program. So I fork/exec w/o waiting for ls and grep. Finally if there's no &, then I wait for the last program, sed. If there is an &, then I just don't wait for sed either.
I talked to my professor about this, and he gave me a fuddled answer like, "I wouldn't have done it that way." However, that's not saying that it's wrong. He said he would have done his piping by having the child fork every extra process. I don't see how this is feasible. As you can see, the parent forks every child, so the depth of children is only ever 1. If I wanted to make a process group, how else is that possible unless my_shell is the one who forks all the children?
tl;dr My parent (my_shell) forks every process of a pipeline and doesn't wait for any except the last program, is this correct?
I've already turned this assignment in but it's driving me up the wall on how to correctly implement multiple pipes. As for this week, I have to implement job control, hence why I don't see how that's possible unless the process group is made by my_shell where my_shell forks every process itself.