🛠️ Linux Automation Toolkit

Bash scripting • Cron jobs • Git workflow • Docker containerization
Part of my CompTIA Linux+ XK0-005 hands on study path.

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📌 Project Goal

Automate routine Linux administration tasks with a Bash script, schedule it via cron and containerize it with Docker for portable execution.

Feature	What it Proves
Bash script (disk_alert.sh)	Command line fluency, I/O redirection, conditions
Cron job	Recurring automation and log management
Dockerfile	Container basics and reproducible builds
GitHub repo	Version-controlled, well documented portfolio artifact

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📂 Folder Structure

linux-automation-toolkit/
├── scripts/
│   └── disk_alert.sh          # disk usage monitoring script
├── cron/
│   └── daily-job.txt          # crontab entry (runs 08:00 daily)
├── docker/
│   ├── Dockerfile             # container build instructions
│   └── disk_alert.sh          # script copy used in the image
├── docs/
│   ├── bash-basics.md         # quick Bash recap
│   └── version-control-notes.md
├── screenshots/               # proof-of-work images
│   ├── 01-disk-alert-script-nano.png
│   ├── 02-disk-alert-script-execution.png
│   ├── 03-disk-alert-log-output.png
│   ├── 04-cron-disk-alert-entry.png
│   └── 05-docker-run-disk-alert.png
└── README.md

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📜 disk_alert.sh (Bash Script)

Monitors / disk usage and appends a status line to /var/log/disk_alert.log.

#!/bin/bash
LOGFILE="/var/log/disk_alert.log"
THRESHOLD=80

USAGE=$(df / | tail -1 | awk '{print $5}' | tr -d '%')

if [ "$USAGE" -ge "$THRESHOLD" ]; then
    MESSAGE="$(date): WARNING – Disk usage is at ${USAGE}%"
else
    MESSAGE="$(date): OK – Disk usage is at ${USAGE}%"
fi

echo "$MESSAGE" >> "$LOGFILE"

• Key Bash concepts:* shebang, variables, command substitution, awk, comparison operators, redirection.

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📅 Cron Job Automation

Step	Command	Purpose
1️⃣	sudo crontab -e	Edit root crontab
2️⃣	Add line → 0 8 * * * /Users/carlossemeao/linux-automation-toolkit/scripts/disk_alert.sh	Run script daily @ 08:00
3️⃣	sudo crontab -l	Confirm job installed

📸 Screenshot:

Log sample:

Wed 11 Jun 2025 08:00:01 BST: OK – Disk usage is at 9%

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🐳 Docker Container Execution

A minimal image runs the script in isolation.

docker/Dockerfile

FROM debian:bullseye-slim
RUN apt-get update && apt-get install -y bash coreutils && rm -rf /var/lib/apt/lists/*
RUN mkdir -p /var/log
COPY disk_alert.sh /usr/local/bin/disk_alert.sh
RUN chmod +x /usr/local/bin/disk_alert.sh
CMD ["/usr/local/bin/disk_alert.sh"]

🔧 Build & Run

cd linux-automation-toolkit
docker build -t disk_alert.img ./docker
docker run --rm disk_alert.img

📸 Screenshot:

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📸 Development Screenshots

#	Description	Image
1	Script written in nano
2	Manual execution test
3	Log output on host
4	Cron job entry
5	Docker container output

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🧠 Lessons Learned

• Bash: variables, loops, conditions, logging
• Cron: scheduling, redirection to log files
• Docker: Dockerfile basics, custom entrypoint, container testing
• Git: clean repo structure, meaningful commits, Markdown documentation

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🚀 How to Extend

• Parameterize the script to monitor multiple mount points.
• Add email or Slack notifications on warning.
• Use Docker volumes to persist logs outside container.
• Integrate this with Ansible for fleet wide deployment.

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📜 License

MIT