Bash Scripting — Introduction to Automation
What You’ll Learn in This Chapter
Welcome to Chapter 29 — where everything you’ve learned so far comes together. You’ve mastered variables, loops, functions, error handling, and text processing. Now it’s time to put those skills to work by automating real tasks.
Automation is the heart of DevOps and system administration. If you find yourself running the same command more than twice, it’s time to automate it.
🧠 “Automate the boring stuff so you can focus on the interesting stuff.”
Why Automation Matters
Think about your daily workflow:
- Backing up files before a deployment
- Cleaning up old logs that eat disk space
- Restarting services after a config change
- Generating reports from log files
Each of these tasks takes 5–15 minutes manually. Over a week, that’s hours of repetitive work. A well-written script does it in seconds — reliably, every single time.
Chapter Roadmap
Here’s what we’ll cover in this chapter:
| # | Topic | What You’ll Learn |
|---|---|---|
| 1 | What to Automate | Identifying automation candidates and calculating ROI |
| 2 | cron vs at vs systemd timers | Scheduling one-time and recurring tasks |
| 3 | Writing Automation-Ready Scripts | Making scripts safe for unattended execution |
| 4 | Automated Backup Script | Building a production-grade backup solution |
| 5 | Log Rotation and Cleanup | Managing disk space with automated cleanup |
| 6 | Practice Exercises | Hands-on challenges to cement your skills |
Prerequisites
Before diving in, make sure you’re comfortable with:
- Functions and error handling (Chapters 15–16)
- File operations and text processing (Chapters 20–24)
- Command-line arguments and getopts (Chapter 17)
- Regular expressions (Chapter 25)
The Automation Mindset
Great automation isn’t just about writing scripts. It’s about thinking systematically:
1. Identify → What task is repeated?
2. Document → What are the exact steps?
3. Script → Convert steps into code
4. Test → Verify in a safe environment
5. Schedule → Set it to run automatically
6. Monitor → Confirm it keeps working
Every script in this chapter follows this lifecycle. By the end, you’ll have a toolkit of real, production-ready automation scripts.
Quick Taste — A 10-Line Automation Script
Here’s a preview of what automation looks like:
#!/usr/bin/env bash
set -euo pipefail
# Clean up temp files older than 7 days
LOG_DIR="/var/log/myapp"
DAYS=7
echo "[$(date '+%F %T')] Starting cleanup of files older than ${DAYS} days"
find "${LOG_DIR}" -type f -name "*.log" -mtime +${DAYS} -delete
echo "[$(date '+%F %T')] Cleanup complete"
Simple, structured, and safe. That’s the goal for every script you’ll write in this chapter.
Let’s Get Started
Head over to What to Automate to learn how to identify the best candidates for automation.
Next: What to Automate →
