LinuxLingo

Purav Mahesh – Project Portfolio Page

Overview

LinuxLingo is an educational CLI application that teaches Linux commands through interactive practice and exam-style assessments. It combines a virtual shell simulator with a comprehensive quiz system, allowing students to safely practice Linux commands in an isolated file system environment and test their knowledge through multiple question types.

I was the primary developer of the Exam module, designing and implementing the end-to-end exam experience. The module enables structured exams with three question types (MCQ, fill-in-the-blanks, and practical shell exercises), instant feedback, and scoring. My implementation spans question data models and parsing pipelines, session management and interactive workflows, to comprehensive grading, feedback, and results reporting—emphasizing robustness, maintainability, and seamless CLI user experience.

Contributions

Code: RepoSense Dashboard

Enhancements:

• Exam Workflow: Orchestration system supporting three entry modes (interactive, direct CLI args, random question selection). Implemented ExamSession, ExamCommandParser, and state transitions across three question types (MCQ, FITB, PRAC) with context-aware control commands (quit, abort, exit) enabling flexible exam interruption.
• Question Parsing: Built robust, extensible pipeline for loading pipe-delimited question files with type-specific parsers and validation. Handles regex-based splitting, escaped pipes, 5 checkpoint verification types, and setup item parsing for PRAC initialization. Includes graceful error handling that skips malformed lines with warnings.
• Session Management: Implemented state machine orchestrating complete exam sessions using ExamSession.runExam() with QuestionInteraction for centralized answer collection. Applied VFS factory pattern for test isolation in practical questions, defensive programming (null checks, state validation), and supports partial completion when users abort mid-exam.
• Grading & Feedback: Polymorphic Question.checkAnswer() with type-specific logic — McqQuestion (case-insensitive A-D matching), FitbQuestion (exact string matching), PracQuestion (VFS verification). Calculates score, percentage, letter grade, and displays structured feedback (✓/✗ + explanation).
• Practical Questions: PRAC question system enabling hands-on, auto-graded shell exercises with Checkpoint supporting 5 verification types (DIR, FILE, NOT_EXISTS, CONTENT_EQUALS, PERM) and SetupItem for VFS pre-configuration (MKDIR, FILE, PERM). Factory pattern creates fresh VFS per question for test isolation.
• Testing & Quality: Comprehensive unit tests covering parsing, grading, session logic, and edge cases (invalid inputs, malformed questions, skipped/aborted exams). Achieved high coverage for critical exam paths; refactored code to eliminate duplication and ensure separation of concerns.

Documentation:

• User Guide: Authored comprehensive Exam System section documenting exam modes, commands (4 invocation formats with examples), interactive flow, in-exam control commands with context-dependent behavior table (MCQ/FITB vs. PRAC), question types with answer instructions, PRAC workflow examples, and edge case handling.
• Developer Guide: Authored 3 major sections — Exam Session Flow, Exam Component (Practical Questions), and Question Parsing and Loading. Covered exam module architecture (entry points, orchestration, integration), question types & grading logic, control command design decisions, parsing pipeline details (tokenization, type-specific rules, error handling), and checkpoint verification examples. Created 8 UML diagrams: 2 class diagrams (ExamClassDiagram.puml, PracQuestionClassDiagram.puml), 4 sequence diagrams (ExamSessionSequence.puml, ExamControlCommandsSequence.puml, PracQuestionSequence.puml, McqFitbAnswerInteractionSequence.puml), and 2 activity diagrams (PracQuestionSetupActivity.puml, McqFitbLineParsingActivity.puml).

Team Contributions:

• Code reviews: #152, #212, #94
• Infrastructure: Question parsing framework, exam command handling, VFS factory pattern
• Issue management for Exam module, thorough testing & bug identification, infrastructure enhancements

Contributions Beyond the Team

• Reported 10 bugs in another team’s project: PE-D Bug Reports