🔄 Daily systemd Logs Backup Script

This project contains a Bash script that extracts daily logs from a specified systemd service and automatically backs them up to this GitHub repository. It is designed for system administrators, developers, and DevOps teams who want a simple, auditable way to preserve logs over time.

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🚀 Features

• ✅ Extracts logs from any systemd unit using journalctl
• ✅ Saves logs to timestamped .log files
• ✅ Skips empty logs automatically
• ✅ Commits new logs to Git
• ✅ Pushes changes to the main branch of a GitHub repository

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📜 Script: save_logs.sh

Copy and paste this into a file using nano save_logs.sh:

#!/bin/bash

# === Configuration ===
UNIT_NAME="your_service_name"             # ← Replace with your systemd service name
REPO_DIR="$HOME/github-log-backups"      # ← Local path to your cloned GitHub repo
LOG_DIR="$REPO_DIR/logs"

# Ensure the log directory exists
mkdir -p "$LOG_DIR"
cd "$REPO_DIR" || exit 1

# === Timestamps ===
NOW_HUMAN=$(date "+%Y-%m-%d 00:00:00")
YESTERDAY_HUMAN=$(date -d "1 day ago" "+%Y-%m-%d 00:00:00")
NOW_FILENAME=$(date "+%Y-%m-%d")
YESTERDAY_FILENAME=$(date -d "1 day ago" "+%Y-%m-%d")

# === Log file path ===
LOG_FILE="$LOG_DIR/${UNIT_NAME}_logs_${YESTERDAY_FILENAME}_to_${NOW_FILENAME}.log"
echo "📄 Saving logs from $YESTERDAY_HUMAN to $NOW_HUMAN into $LOG_FILE"

# === Collect logs ===
sudo journalctl -u "$UNIT_NAME" --since "$YESTERDAY_HUMAN" --until "$NOW_HUMAN" --no-pager -o short-iso > "$LOG_FILE"

# === Skip if log file is empty ===
if [ ! -s "$LOG_FILE" ]; then
  echo "⚠️ Log file is empty. Removing it."
  rm -f "$LOG_FILE"
  exit 0
fi

# === Git: Commit and Push ===
echo "✅ Logs saved. Committing to GitHub."

# Set Git identity if needed (optional for automation)
git config pull.rebase true
git config user.name "log-bot"
git config user.email "[email protected]"

git add "$LOG_FILE"
git commit -m "Add ${UNIT_NAME} logs: ${YESTERDAY_FILENAME} to ${NOW_FILENAME}"
git pull --rebase origin main
git push origin main

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📦 Installation & Setup

1. Create a GitHub repository

Create a private GitHub repository named for example: log-backups. Do not initialize it with a README.

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2. Clone the repository using SSH

⚠️ Make sure your GitHub account has an SSH key added, and you're using the [email protected]:... SSH format.

git clone [email protected]:yourusername/log-backups.git ~/github-log-backups
cd ~/github-log-backups

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3. Make the script executable

chmod +x save_logs.sh

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4. Edit the configuration in save_logs.sh

Update these variables at the top of the script:

UNIT_NAME="your_service_name"         # e.g. nginx, docker, your-custom-service
REPO_DIR="$HOME/github-log-backups"  # path to this repo

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5. Add your SSH key to GitHub (if not already)

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_rsa

Ensure your SSH public key is added to GitHub.

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🛠 How It Works

1. The script uses journalctl to pull logs from the past 24 hours.
2. It saves them to a file named like:

   logs/your_service_name_logs_2025-06-08_to_2025-06-09.log
   

3. If the log is not empty, it commits the file to Git and pushes it to GitHub.

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⏰ Automate with Cron

To run the script every day at midnight:

1. Open crontab:

crontab -e

2. Add this line:

0 0 * * * /bin/bash $HOME/github-log-backups/save_logs.sh >> /var/log/save_logs.log 2>&1

This will run the script daily and write any output to /var/log/save_logs.log.

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🔐 Optional: Avoid sudo in journalctl

If you want to run the script without sudo:

sudo usermod -aG systemd-journal $USER

Then log out and log back in.

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📁 Output Example

logs/
├── nginx_logs_2025-06-08_to_2025-06-09.log
├── nginx_logs_2025-06-09_to_2025-06-10.log

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