Signal: KILL

This signal causes a process to terminate immediately. It cannot be caught or ignored. This is always signal #9 on all systems.

Do not use this signal lightly. The process will not have any chance to clean up. It may leave behind orphaned child processes, temporary files, allocated locks, active shared memory segments, busy sockets, and any number of other resource state inconsistencies. This can lead to surprising and hard to debug problems in the subsequent operation of the system.


  • ZombieProcesses in the "Z" state cannot be killed: they are dead already, and are merely waiting for their parents to collect their exit code.
  • Processes that are blocked in the "D" state will not die until they recover from their D status.