What is the purpose of fork()?

Question

In many programs and man pages of Linux, I have seen code using fork(). Why do we need to use fork() and what is its purpose?

Answer 1

Multiprocessing is central to computing. For example, your IE or Firefox can create a process to download a file for you while you are still browsing the internet. Or, while you are printing out a document in a word processor, you can still look at different pages and still do some editing with it.