20. Recursive Directory Size Calculator with Filtering
1. Hello, World!
2. Rename Photos by Capture Date
3. Organize Downloads Folder by File Type
4. Delete Old Log Files Automatically
5. Find Duplicate Files Using MD5 Hashing
6. Generate Comprehensive File Inventory
7. Parse Web Server Logs for Performance Metrics
8. Extract Emails, URLs, and Phone Numbers from Text
9. Track Daily and Monthly Active Users from Apache Logs
10. Generate Formatted Text Reports with Column Alignment
11. Analyze Sales Transactions and Generate Revenue Reports
12. Clean and Validate CSV Data
13. Convert JSON API Responses to CSV
14. Parse and Validate Configuration Files
15. Build a CLI Calculator with Argument Parsing
16. Parse and Display Weather Data from JSON
17. Build a Simple Inventory System with Classes
18. Generate Markdown Table from CSV Data
19. Aggregate Sales Data by Time Period
20. Recursive Directory Size Calculator with Filtering
21. Parse and Transform XML Configuration Files
22. Find and Replace Across Multiple Files
23. Build a Simple Template Engine
24. CSV Data Validator with Business Rules
25. Build a Multi-Format Log Analyzer

Challenge

Problem

Understanding disk usage is crucial for system administration and application optimization. This drill teaches you to recursively traverse directories, calculate file sizes, filter by file types, and format output for human readability. You'll learn recursive algorithms, directory traversal, file metadata access, and data formatting—essential skills for building DevOps tools, backup systems, and disk usage analyzers.

Difficulty: Intermediate

Instructions

  1. Read target directory path from config.txt
  2. Recursively scan all files and subdirectories
  3. Calculate total size in bytes
  4. Group files by extension and calculate size per extension
  5. Sort extensions by size (largest first)
  6. Format output:
    'DIRECTORY SIZE ANALYSIS'
    'Directory: [path]'
    '=' * 50
    'BY FILE TYPE'
    '.ext: X.XX MB (Y files)' (for each extension, sorted by size)
    'No extension: X.XX MB (Y files)' (if any)
    '-' * 50
    'SUMMARY'
    'Total Files: X'
    'Total Size: X.XX MB'
  7. Format sizes: bytes -> KB -> MB -> GB as appropriate
  8. Handle empty directories gracefully

Files

Editable
Read-only

Hints

Hint 1

Find.find(path) recursively yields every file and directory

Hint 2

File.directory?(path) checks if path is a directory

Hint 3

File.size(path) returns file size in bytes

Hint 4

File.extname(path) returns extension including the dot (e.g., '.txt')

Hint 5

Use 'next' to skip directories in the Find.find loop

Hint 6

Hash.new { |h, k| h[k] = { size: 0, count: 0 } } creates nested default hash

Hint 7

Sort by size descending: array.sort_by { |k, v| -v[:size] }

Hint 8

1024 bytes = 1 KB, 1024 KB = 1 MB, 1024 MB = 1 GB

Provided Files (Read-only)

1. Directory with multiple file types

Input: 
analyze_directory('config.txt')
Expected Output: 
DIRECTORY SIZE ANALYSIS
Directory: /test_dir
==================================================
BY FILE TYPE
.txt: 2.81 KB (3 files)
.rb: 500 bytes (1 files)
.json: 300 bytes (1 files)
--------------------------------------------------
SUMMARY
Total Files: 5
Total Size: 3.59 KB

2. Large files with MB sizes

Input: 
analyze_directory('config.txt')
Expected Output: 
DIRECTORY SIZE ANALYSIS
Directory: /large_dir
==================================================
BY FILE TYPE
.mp4: 2.38 MB (1 files)
.jpg: 1.43 MB (1 files)
.pdf: 488.28 KB (1 files)
--------------------------------------------------
SUMMARY
Total Files: 3
Total Size: 4.29 MB

3. Files without extensions

Input: 
analyze_directory('config.txt')
Expected Output: 
DIRECTORY SIZE ANALYSIS
Directory: /mixed_dir
==================================================
BY FILE TYPE
No extension: 1.46 KB (2 files)
.txt: 300 bytes (1 files)
--------------------------------------------------
SUMMARY
Total Files: 3
Total Size: 1.76 KB
+ 2 hidden test cases