2.6 Tracing Parent and Child Processes

When a process forks, it creates a child process that is effectively a copy of its parent process, but with a different process ID. For information about other differences, see the fork(2) manual page. The child process can either run independently from its parent process to perform some separate task. Or, a child process can execute a new program image that replaces the child's program image while retaining the same process ID.