Linux trap Guide

Linux trap Guide

Complete beginner-friendly guide to trap on Linux, covering Arch Linux, CachyOS, and other distributions including signal handling, cleanup on exit, and script error handling.

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Table of Contents

1. Understanding trap
2. trap Basics
3. Signal Handling
4. Cleanup on Exit
5. Troubleshooting

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Understanding trap

What is trap?

trap catches signals and executes commands.

Uses:

• Signal handling: Handle signals
• Cleanup: Clean up on exit
• Error handling: Handle errors
• Script safety: Make scripts safer

Why it matters:

• Cleanup: Ensure cleanup happens
• Error handling: Handle errors gracefully
• Script safety: Make scripts robust

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trap Basics

Trap Signal

Basic usage:

# Trap signal
trap 'command' SIGNAL

# Executes command on signal

Common Signals

Common signals:

# Trap EXIT
trap 'cleanup' EXIT

# Trap INT (Ctrl+C)
trap 'echo "Interrupted"' INT

# Trap TERM
trap 'cleanup' TERM

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Signal Handling

Multiple Signals

Trap several:

# Multiple signals
trap 'cleanup' INT TERM EXIT

# Handles all three

Ignore Signal

Ignore signal:

# Ignore signal
trap '' INT

# Empty string = ignore

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Cleanup on Exit

Cleanup Function

In scripts:

#!/bin/bash
cleanup() {
    echo "Cleaning up..."
    rm -f /tmp/tempfile
}

trap cleanup EXIT

# Script continues
# Cleanup runs on exit

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Troubleshooting

trap Not Working

Check syntax:

# Verify trap syntax
trap -p

# Shows current traps

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Summary

This guide covered trap usage, signal handling, and cleanup for Arch Linux, CachyOS, and other distributions.

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Next Steps

• Bash Scripting Guide - Scripting
• kill Guide - Send signals
• trap Documentation: man trap

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This guide covers Arch Linux, CachyOS, and other Linux distributions. For distribution-specific details, refer to your distribution's documentation.