Practice Use drills for recall and labs for real operating judgment.

LAB-PROC-03 - Signals and Controlled Stopping

Understand basic process signals and practice stopping harmless processes with a preference for gentler signals first.

PS Process Management

Signals and Controlled Stopping

Understand basic process signals and practice stopping harmless processes with a preference for gentler signals first.

35 min INTERMEDIATE LINUX Curriculum-reviewed
Prerequisites
Lab LAB-PROC-01 - The Process Lifecycle Lab LAB-PROC-02 - Live Monitoring: top and htop
Success criteria
  • Use kill with a harmless target process.
  • Explain why SIGTERM should usually come before SIGKILL.
Safety notes
  • Only target harmless lab processes you created yourself.

Part A: The Field Guide

The kill command sends a signal. It does not magically mean “destroy this process” every time.

For this lab, the most important signals are:

  • SIGTERM for a normal stop request
  • SIGKILL for force when normal stopping fails
  • SIGINT as the signal behind Ctrl+C

Good Default

Try a normal stop first. Force is a later step, not the first habit.

Part B: The Drill Deck

Terminal required: create only harmless targets and stop only those.

G
Guided Step by step - type exactly this and compare the result
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Exercise G1: Create a harmless target

  1. Run sleep 300 &
  2. Run pgrep sleep
  3. Note the PID

Exercise G2: Send a normal stop request

  1. Run kill <PID>
  2. Wait a moment
  3. Run pgrep sleep
  4. Confirm the process is gone

Exercise G3: Use Ctrl+C on a foreground process

  1. Run ping localhost
  2. Let it run briefly
  3. Press Ctrl+C
  4. Explain how that differs from killing a background process by PID
S
Solo Task described, hints available - figure it out
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Exercise S1: Compare term versus kill

Create another harmless sleep process and answer in words:

  1. what a polite stop is trying to allow
  2. why a forced stop is more abrupt
  3. why you would avoid the forced route unless needed

Exercise S2: Optional name-based stop

  1. create two harmless sleep processes
  2. verify them with pgrep sleep
  3. stop them with pkill sleep or killall sleep
  4. confirm they are gone
M
Mission Real scenario - no hints, combine multiple skills
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Mission M1: Build a safe stop sequence

Describe the sequence you would follow before stopping a process on a real machine:

  1. identify the exact process
  2. verify the PID or name
  3. decide whether a normal stop is appropriate
  4. confirm the result afterward

If that sequence is clear in your head, you are building the right operational habit.