Command-line interrupts in OS X vs Linux

Question

Occasionally, when I'm developing on my Mac, I'll get a process that hangs. When that happens, I'll try the following:

1. Ctrl + C in the active terminal window
2. If nothing happens, I'll open a new terminal window and do kill -SIGTERM {PID}
3. If still nothing, close the terminal window.

I'm running into situations where after doing both 1 and 2, the PID is still listed in my list of processes. In other words, there doesn't seem to be a command-line option to kill the process - all I can do is kill terminal.

In Linux command-line environments, we obviously don't have option 3. So do command-line interrupts operate differently there? Is there another way to kill processes I'm overlooking? What is the 'last resort' option for killing a Linux process?

Answer 1

Same as in OS X: Send SIGKILL.

Answer 2

You can try Ctrl + \ (control backslash), which sends the QUIT signal. This often works when SIGINT has been trapped.

Sometimes a process will ignore signals, because it is stopped.

You can use something like this, to kill a process gracefully if possible:

KILL() {
  kill -CONT "$@"
  kill -TERM "$@"
  kill -HUP "$@"
  sleep 1
  kill -KILL "$@"
}

KILL 12345

Even this might not always work. If there is some I/O error, such as a missing device, for example.