Backup and recovery strategies in Raspberry Pi - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Raspberry Pi backup script snippet?

Consider this Python script running on a Raspberry Pi to create a backup of a directory. What will be printed after execution?

Raspberry Pi

import os
backup_dir = '/home/pi/backup'
source_dir = '/home/pi/data'
os.system(f'mkdir -p {backup_dir}')
os.system(f'cp -r {source_dir}/* {backup_dir}/')
print('Backup completed')

A SyntaxError

B Backup completed

C FileNotFoundError

D Permission denied

💡 Hint

The script creates the backup directory if it doesn't exist and copies files.

The script uses os.system to create the backup directory and copy files. If the directories exist and permissions are correct, it prints 'Backup completed'.

❓ Predict Output

intermediate

What error does this recovery script raise?

This Python snippet attempts to restore files from a backup folder on a Raspberry Pi. What error will it raise if the backup folder does not exist?

Raspberry Pi

import shutil
backup_dir = '/home/pi/backup'
restore_dir = '/home/pi/data'
shutil.copytree(backup_dir, restore_dir)

A FileNotFoundError

B PermissionError

C KeyError

D SyntaxError

💡 Hint

copytree requires the source directory to exist.

If the source directory does not exist, shutil.copytree raises FileNotFoundError.

🧠 Conceptual

advanced

Which backup strategy minimizes data loss on a Raspberry Pi?

You want to back up your Raspberry Pi data regularly. Which strategy best minimizes data loss if the Pi crashes unexpectedly?

A Full backup once a month

B Differential backup once a week

C Incremental backup every hour

D No backup, just copy files manually

💡 Hint

Think about how often data changes and how quickly you want to recover.

Incremental backups every hour save only changes since the last backup, minimizing data loss and storage use.

❓ Predict Output

advanced

What is the output of this Raspberry Pi backup verification script?

This Python script checks if the backup directory contains the expected number of files. What will it print if the backup has exactly 5 files?

Raspberry Pi

import os
backup_dir = '/home/pi/backup'
files = os.listdir(backup_dir)
if len(files) == 5:
    print('Backup verified')
else:
    print('Backup incomplete')

A PermissionError

B Backup incomplete

C FileNotFoundError

D Backup verified

💡 Hint

The script counts files and compares to 5.

If the backup directory has exactly 5 files, the script prints 'Backup verified'.

❓ Predict Output

expert

What is the value of variable 'status' after running this Raspberry Pi backup script?

This Python script attempts to back up a directory and sets 'status' based on success. What is the value of 'status' after running?

Raspberry Pi

import subprocess
backup_dir = '/home/pi/backup'
source_dir = '/home/pi/data'
try:
    subprocess.run(['cp', '-r', source_dir + '/*', backup_dir], check=True)
    status = 'Success'
except subprocess.CalledProcessError:
    status = 'Failed'

A Failed

B Success

C SyntaxError

D FileNotFoundError

💡 Hint

Check how subprocess.run handles shell wildcards without shell=True.

The wildcard '*' is not expanded without shell=True, so the command fails and status is set to 'Failed'.