SIGKILL Signal Explained (Signal 9)
What the Linux SIGKILL signal does and when it's used.
Published October 23, 2026
SIGKILL (signal number 9) immediately and forcefully terminates a process; it cannot be caught, blocked, or ignored.
Key points
- The process has no opportunity to clean up open files or release resources before exiting
- Use as a last resort — kill -9 <PID> — when a process doesn't respond to a normal SIGTERM