8 Matching Annotations
  1. Feb 2021
    1. I am trying to understand how CTRL+C terminates a child but not a parent process. I see this behavior in some script shells like bash where you can start some long-running process and then terminate it by entering CTRL-C and the control returns to the shell. Could you explain how does it work and in particular why isn't the parent (shell) process terminated? Does the shell have to do some special handling of CTRL+C event and if yes what exactly does it do?
    1. The CTRL-\ key sends a kill signal to the foreground job which, under normal circumstances, is guaranteed to terminate it. This signal cannot be captured by a process. However, this means the process cannot cleanup and is just summarily stopped. In some cases, a process can be stuck in a kernel wait state so this signal never reaches it. In that case, the process is unusable but cannot be killed.
  2. Oct 2018