Lesson 68 of 69

8 mins read

Capstone Mini-Project: Automated Backup & Health Dispatcher

In Plain English

Build a production-grade Bash CLI utility from scratch: incorporates `set -euo pipefail`, atomic `mkdir` locking, argument parsing with `case`, automated `.tar.gz` directory backups, retention pruning, disk/RAM health monitoring, and cleanup traps.

The Mental Model

"Building a complete, standalone automated tool ready to deploy to live Linux servers and cloud infrastructure."

Deep Dive: How It Works

Step 1: Parse CLI command modes (`backup`, `health`, `all`).

Step 2: Acquire atomic lockfile with cleanup trap.

Step 3: Archive designated target directories with timestamped `.tar.gz` files.

Step 4: Prune backups older than retention policy.

Step 5: Output structured status summary with exit codes.

Syntax Blueprint

#!/usr/bin/env bash
set -euo pipefail

# Lock acquisition
LOCK="/tmp/zen_app.lock"
mkdir "$LOCK" && trap "rm -rf '$LOCK'" EXIT

# Execute backup and health checks...

Capstone combines strict mode, locks, tar archiving, and health checks.

Core Rules to Remember

Full Production Architecture: Combines all 9 prior modules into a cohesive utility script.

Robust Error Handling: Traps handle unexpected exits, cleanly releasing locks and cleaning temp files.

Deployable Ready: Ready to be placed in /usr/local/bin and scheduled with cron.

Common Beginner Traps & How to Fix Them

Mistake:Leaving temporary files behind when a script encounters an unexpected error.

Why it happens: Without an EXIT trap, manual cleanup code at the end of the script is never reached.

How to fix: Always register cleanup handlers with `trap cleanup EXIT`.

Pro Tip: Make your script self-documenting by including a `--help` case handler explaining usage, flags, and examples.

Live Interactive Example

Hit Run Code to see it live

Full Capstone Utility Execution

Git 2.45 / CLI

#!/bin/bash
set -euo pipefail

WORKSPACE="/tmp/zen_capstone"
BACKUP_DIR="$WORKSPACE/backups"
SRC_DIR="$WORKSPACE/source"
LOCK_DIR="$WORKSPACE/job.lock"

# Setup directories
mkdir -p "$BACKUP_DIR" "$SRC_DIR"
echo "Project Code v1.0" > "$SRC_DIR/app.js"
echo "Secret Config" > "$SRC_DIR/config.env"

# Atomic lock
if ! mkdir "$LOCK_DIR" 2>/dev/null; then
  echo "Error: Lock acquisition failed."
  exit 1
fi

cleanup() {
  rm -rf "$LOCK_DIR"
  echo "[Trap] Lock released successfully."
}
trap cleanup EXIT

# 1. Create Timestamped Backup
TIMESTAMP=$(date +'%Y%m%d_%H%M%S')
ARCHIVE="$BACKUP_DIR/backup_$TIMESTAMP.tar.gz"
tar -czf "$ARCHIVE" -C "$SRC_DIR" .
echo "[Backup] Created archive: $ARCHIVE ($(wc -c < "$ARCHIVE") bytes)"

# 2. System Health Summary
echo "[Health] Memory Total: $(awk '/MemTotal/ {print int($2/1024)}' /proc/meminfo) MB"
echo "[Health] Disk Available: $(df -h / | awk 'NR==2 {print $4}')"

echo "=========================================="
echo "    CAPSTONE PROJECT EXECUTED CLEANLY    "
echo "=========================================="

rm -rf "$WORKSPACE"

Output Console

Click "Run Code" to view the rendered output.

How it works: The capstone acquired an atomic lock, created a compressed tarball, reported health metrics, and cleaned up.

Your Turn: Micro Challenge

No pressure! Edit the starter code below and test your solution with instant feedback.

Micro Exercise

Run the Capstone Mini-Project

Echo "CAPSTONE PROJECT EXECUTED CLEANLY" to complete the practical project challenge.

Sandbox Output

Click "Run & Check" to test your solution.

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