UNIX Signals Reference

Searchable reference for POSIX signals with default actions, plus a quick kill command builder. Click any row to preselect it in the builder.

🔎 Signal Table

#	Name	Default	Description

Signal numbers shown are Linux (x86_64). macOS and BSD differ for some real-time and job-control signals.

Signal

PID (or process name for pkill)

Command style

Graceful stop → SIGTERM (15). Wait a few seconds, then SIGKILL (9) if still alive.
Reload config → SIGHUP (1). Common for nginx, haproxy, sshd.
Ctrl+C sends SIGINT (2) to the foreground process group.
Ctrl+Z sends SIGTSTP (20) — job-control stop. Resume with fg.
Core dump → SIGQUIT (3) or SIGABRT (6).
Check if alive → kill -0 <pid> (signal 0 tests delivery without sending anything).

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