--- title: kill — terminate processes date: 2026-10-17 time: 12:00 model: admin category: programs author_type: human summary: A command that sends a signal to terminate a process. Differences between SIGTERM and SIGKILL, examples of restarting to apply settings, and execution screens. tags: program, Service and process management, kill --- **💬 "kill command"** - **Concept**: Sends a signal to a running process to terminate it or make it reread its configuration. The target is specified by PID. - **Output structure**: On success, it prints nothing. If the PID does not exist, it returns the No such process error. - **Practical recommendation**: First terminate gracefully with the default kill PID(SIGTERM), and use kill -9 only when there is no response. - **-15 (SIGTERM)**: This is the default signal. It asks the process to perform cleanup and exit. - **-9 (SIGKILL)**: This is a forced termination. It ends the process immediately without cleanup, so use it only as a last resort. ## Three essential command combinations - `kill PID` — request a normal termination with the default (SIGTERM) - `kill -9 PID` — force termination when there is no response - `kill -l` — list available signals Here are some additional options worth knowing. - `kill -HUP PID` — make the process reread its configuration without terminating it - Before using kill, verify that the target is correct with `ps -p PID -o pid,cmd` **💬 "Please give me one brief real-world example"** **Scenario**: This is the process of cleaning up an unresponsive web server process step by step. ### Step 1: Verify the target Check that the PID and command are correct. ``` ps -p 4821 -o pid,user,cmd ``` ### Step 2: Request a graceful termination Request termination with the default signal. ``` kill 4821 ``` ### Step 3: Force termination If it is still running, terminate it forcefully. ``` kill -9 4821 ``` ## Real execution screenshot This is an example screen showing a process being terminated and verified with `kill`. ![kill command execution result: confirm PID and then send termination signal](https://games.aidebatehub.com/assets/kill-demo.png) A real production server --- Source (HTML): https://games.aidebatehub.com/programs/linux/services/kill.html This file is an auto-generated Markdown twin of the DevHub document.