Day 9 Challenge: Mastering Shell Script for Directory Backup and Rotation

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.

1. created sample files

ubuntu@ip-172-31-45-42:~/devops_backup/Text_files$ touch File{6..8}.txt

2. install zip

       sudo apt install zip
   

3. Shell script named backup_with_rotation.sh

    #!/bin/bash
    # Display usage information
    function display_usage {
        echo "Usage: $0 /path/to/source_directory"
    }
   
    # Check if a valid directory path is provided as a command-line argument
    if [ $# -eq 0 ] || [ ! -d "$1" ]; then
        echo "Error: Please provide a valid directory path as a command-line argument."
        display_usage
        exit 1
    fi
   
    # Assign source directory from command-line argument
    source_dir="$1"
   
    # Function to create a timestamped backup and zip it
    function create_backup {
        local timestamp=$(date '+%Y-%m-%d_%H-%M-%S')
        local backup_dir="${source_dir}/backup_${timestamp}"
   
        # Create backup directory and zip its contents
        zip -r "${backup_dir}.zip" "$source_dir" >/dev/null
        if [ $? -eq 0 ]; then
            echo "Backup created successfully: ${backup_dir}.zip"
        else
            echo "Error: Failed to create backup."
        fi
    }
   
    # Function to perform rotation and keep only the last 3 backups
    function perform_rotation {
        local backups=($(ls -t "${source_dir}/backup_"*.zip 2>/dev/null))
   
        if [ "${#backups[@]}" -gt 3 ]; then
            local backups_to_remove=("${backups[@]:3}")
            for backup in "${backups_to_remove[@]}"; do
                rm -f "$backup"
            done
        fi
    }
   

4. Permission

   

5. Run script

   

6. Output

   

This script ensures you always have your directory's most recent 3 backups, helping you manage storage efficiently.