Day 9 Task: Shell Scripting Challenge Directory Backup with Rotation

Challenge Description

Your task is to create a bash script that takes a directory path as a command-line argument and performs a backup of the directory. The script should create timestamped backup folders and copy all the files from the specified directory into the backup folder.

Additionally, the script should implement a rotation mechanism to keep only the last 3 backups. This means that if there are more than 3 backup folders, the oldest backup folders should be removed to ensure only the most recent backups are retained.

The Script

Below is the Bash script named backup_with_rotation.sh that implements the described functionality:

#!/bin/bash

<< comment
This script is for backup of the work_dir with 5 day rotation
comment

SOURCE="/home/ubuntu/work_dir"
TIME_STAMP=$(date +%Y_%m_%H_%M%S)
DEST="/home/ubuntu/backup"

# Function to create backup
function create_backup {
    zip -r "$DEST/backupfile_${TIME_STAMP}.zip" "$SOURCE" >/dev/null

    if [ $? -eq 0 ]; then
        echo "Backup generated successfully for $TIME_STAMP"
    fi
}

# Function to remove old backups beyond the 5-day rotation
function rotation_backup {
    backups=($(ls -t "$DEST/backup"*zip))
    backups_to_remove=("${backups[@]:5}")

    for i in "${backups_to_remove[@]}"; do
        rm -rf $i
    done
}

# Main execution
create_backup
rotation_backup

How It Works:

1. Defining Variables:

   • SOURCE is the directory to be backed up.

   • TIME_STAMP creates a unique identifier for each backup based on the current date and time.

   • DEST is the destination directory for storing backups.

2. Creating Backups:

   • The create_backup function compresses the SOURCE directory into a zip file named with the current timestamp.

   • It verifies if the backup is successfully created and provides feedback.

3. Managing Backup Rotation:

   • The rotation_backup function lists the existing backups sorted by modification time.

   • It then removes backups older than the most recent five, maintaining a five-day rotation.

Backup Rotation: The script rotates the last five backups, automatically removing the oldest ones to manage storage space efficiently.

By automating this process, I ensure that my work is consistently backed up without manual intervention, and old backups are pruned regularly to avoid consuming unnecessary storage.