The script does the following:

1. Comprehensive Logging System:

• Dedicated log directory and rotation
• Configurable log file size limits
• Different log levels (INFO, WARN, ERROR)
• Verbose mode option
• Log rotation when size limit is reached

2. Robust Error Handling:

• Error codes for different failure scenarios
• Detailed error messages with timestamps
• Temporary file handling for error capture
• Proper cleanup of temporary files
• Error handling for all critical operations

3. Process Management:

• Lock file mechanism to prevent multiple instances
• Proper cleanup of lock file using trap
• Stale lock detection and cleanup

4. Input Validation:

• Parameter validation for numeric inputs
• Better argument parsing
• Clear help message with usage examples

5. Safety Features:

• Separate functions for snapshot creation and deletion
• Better status checking and error reporting
• Verbose logging option for debugging
• Dry-run mode improvements

6. Code Organization:

• Modular function design
• Clear separation of concerns
• Constants and configuration at the top
• Main function to orchestrate operations
• Better variable naming and scope management

To use the script:

1. Save it to a location like /usr/local/sbin/proxmox-snapshot-rotation.sh
2. Make it executable: chmod +x /usr/local/sbin/proxmox-snapshot-rotation.sh
3. Create the log directory: mkdir -p /var/log/proxmox-snapshots

You can run it with various options:

# Normal run
./proxmox-snapshot-rotation.sh

# Dry run with verbose output
./proxmox-snapshot-rotation.sh --dry-run --verbose

# Keep more snapshots and longer retention
./proxmox-snapshot-rotation.sh --keep 48 --retain-days 14

The script will create detailed logs in /var/log/proxmox-snapshots/ and handle various error conditions gracefully.