Why are process groups needed in UNIX?

Question

*nix-like systems

The question is the following. Why are process groups invented, why do we need a process leader, why are child and parent processes invented, and what logic is it all subject to? Please give a link to materials on the topic if the answer seems too capacious.

Answer 1

Read about fork actually the main process opens a port and creates children, giving them a port and other resources, and depriving them of root rights. This makes sense, well, it also makes sense to allocate memory in the main process and only copy changes in the child ones