Hey there, DevOps enthusiasts! 🌟 Today, on Day 9 of our 90 Days of DevOps challenge, we are diving into an essential topic: Directory Backup with Rotation using shell scripting. 📂🔄

📚 What is Directory Backup with Rotation? 🤔

Imagine you have many important files in a directory, and you want to ensure they're safe. 🔒 A backup is a copy of these files saved somewhere else in case something goes wrong. But if you keep making new backups every day, you might run out of space! 😬

That's where backup rotation comes in. Instead of saving every backup forever, we keep a limited number of recent backups. For example, we can keep the last 7 backups and delete the older ones. This way, we save space while keeping our data safe. 📦💾

🛠️ Let's Create a Backup Script! 🖥️

We'll go through the script step by step to understand each part in detail.

1. Set Variables 📝

Variables are used to store values that our script will use. This makes the script flexible and easy to change without modifying the entire code.

#!/bin/bash

SOURCE_DIR="/path/to/source"
BACKUP_DIR="/path/to/backup"
MAX_BACKUPS=7

#!/bin/bash: This line tells the system that the script should be run using the bash shell.
SOURCE_DIR: This is the directory we want to back up.
BACKUP_DIR: This is where we will store our backups.
MAX_BACKUPS: This is the maximum number of backups we want to keep.

2. Create a New Backup 📦

We use the cp (copy) command to create a backup. To ensure each backup is unique, we add a timestamp to the backup directory name.

TIMESTAMP=$(date +"%Y%m%d%H%M%S")
NEW_BACKUP="$BACKUP_DIR/backup-$TIMESTAMP"

cp -r $SOURCE_DIR $NEW_BACKUP
echo "Backup created: $NEW_BACKUP"

TIMESTAMP=$(date +"%Y%m%d%H%M%S"): This command generates a timestamp in the format YYYYMMDDHHMMSS (Year, Month, Day, Hour, Minute, Second). This ensures each backup has a unique name.
NEW_BACKUP="$BACKUP_DIR/backup-$TIMESTAMP": This creates the full path for the new backup directory.
cp -r $SOURCE_DIR $NEW_BACKUP: This command copies the entire source directory to the new backup directory. The -r flag means "recursive," so it copies all subdirectories and files.
echo "Backup created: $NEW_BACKUP": This prints a message confirming the backup was created.

3. Rotate Old Backups 🔄

Next, we manage old backups to ensure we don't exceed the limit set by MAX_BACKUPS.

cd $BACKUP_DIR

BACKUPS_COUNT=$(ls -1 | wc -l)
if [ $BACKUPS_COUNT -gt $MAX_BACKUPS ]; then
    OLDEST_BACKUP=$(ls -1t | tail -1)
    rm -rf $OLDEST_BACKUP
    echo "Deleted oldest backup: $OLDEST_BACKUP"
fi

cd $BACKUP_DIR: This changes the current directory to the backup directory.
BACKUPS_COUNT=$(ls -1 | wc -l): This counts the number of backups in the backup directory.
- ls -1: Lists all files and directories in the current directory, one per line.
- wc -l: Counts the number of lines.
if [ $BACKUPS_COUNT -gt $MAX_BACKUPS ]; then: This checks if the number of backups is greater than the maximum allowed.
OLDEST_BACKUP=$(ls -1t | tail -1): This finds the oldest backup.
- ls -1t: Lists files and directories sorted by modification time, newest first.
- tail -1: Gets the last line of the output, which is the oldest backup.
rm -rf $OLDEST_BACKUP: This removes the oldest backup directory.
echo "Deleted oldest backup: $OLDEST_BACKUP": This prints a message confirming the deletion.

4. Combine Everything 📝🔄

Putting it all together, we get the complete script:

#!/bin/bash

SOURCE_DIR="/path/to/source"
BACKUP_DIR="/path/to/backup"
MAX_BACKUPS=7

# Create a new backup
TIMESTAMP=$(date +"%Y%m%d%H%M%S")
NEW_BACKUP="$BACKUP_DIR/backup-$TIMESTAMP"
cp -r $SOURCE_DIR $NEW_BACKUP
echo "Backup created: $NEW_BACKUP"

# Rotate old backups
cd $BACKUP_DIR
BACKUPS_COUNT=$(ls -1 | wc -l)
if [ $BACKUPS_COUNT -gt $MAX_BACKUPS ]; then
    OLDEST_BACKUP=$(ls -1t | tail -1)
    rm -rf $OLDEST_BACKUP
    echo "Deleted oldest backup: $OLDEST_BACKUP"
fi

🎉 Congratulations! 🎉

We have just created a script that backs up a directory and rotates old backups! 🚀 This simple automation can save you a lot of time and keep your data safe.💪

Keep following the journey, and let's learn and grow together! 🌱 Don't forget to share your progress and connect with me on LinkedIn. Let's inspire and help each other on this DevOps adventure! 🚀

Happy Learning! 😎

🌟 Day 9 of 90 Days of DevOps Challenge: Directory Backup with Rotation 🚀