LinuxLingo

Wang Ziling — Project Portfolio Page

Project: LinuxLingo

LinuxLingo is a command-line application for learning Linux commands through an interactive shell simulator and a built-in quiz system. It features an in-memory Virtual File System (VFS), a shell parser supporting piping, redirection, and conditional operators, and an exam module with MCQ, fill-in-the-blank, and practical questions. It is written in Java and has about 10 kLoC.

Given below are my contributions to the project.

• Code contributed: RepoSense link

• Project infrastructure and architecture:
  • Designed and implemented the entire project scaffold: the entry point (LinuxLingo), CLI layer (Ui, MainParser), full VFS engine (VirtualFileSystem, FileNode, Directory, RegularFile, Permission, VfsException), shell framework (CommandRegistry, CommandResult, Command interface), exam framework (Question base class, Checkpoint, ExamResult), and storage utilities (Storage, StorageException). This constituted 19 fully-implemented infrastructure files that all team members depended on.
  • Provided 4 reference command implementations (EchoCommand, MkdirCommand, PwdCommand, TouchCommand) as coding pattern examples for the team.
  • Authored both the v1.0 and v2.0 Development Guides with detailed per-member task breakdowns, API references, and an ownership matrix, enabling team members to implement their features independently without coordination overhead.
• New features and enhancements:
  • Implemented v2.0 shell infrastructure: || (OR) and < (input redirect) token support in ShellParser, alias/history/glob fields in ShellSession, JLine integration via ShellCompleter and ShellLineReader, and “Did you mean?” command suggestions.
  • Implemented v2.0 exam enhancements: new Checkpoint types (NOT_EXISTS, CONTENT_EQUALS, PERM), SetupItem inner class and applySetup() in PracQuestion, and enhanced QuestionParser for new checkpoint/setup formats.
  • Implemented DiffCommand and TeeCommand; enhanced multiple existing commands (EchoCommand -e, GrepCommand -l, HeadCommand -N syntax, multi-file support for WcCommand/TailCommand, etc.).
  • Fixed several bugs across the codebase: GrepCommand stdin filtering and -v flag, VfsSerializer empty-file deserialization, QuestionParser escaped-pipe handling, ShellParser single-quote and backslash escaping, ChmodCommand symbolic mode regex, CatCommand -n with piped input, and DateCommand format specifier conversion.
  • Set up JaCoCo test coverage reporting in the Gradle build.
• Testing:
  • Wrote the majority of the project’s test suite, including unit tests for shell components (ShellSessionTest, CdCommandTest, LsCommandTest, BuiltinCommandTest), storage/exam modules (VfsSerializerTest, QuestionParserTest, QuestionBankTest, ExamResultTest), VFS infrastructure (DirectoryTest, PermissionTest, RegularFileTest), and 29 end-to-end integration tests. Also authored v2.0 infrastructure tests and placeholder tests for team members to enable after implementation.
• Documentation:
  • User Guide: Wrote the overall structure/backbone, and the full contents of the Quick Start, FAQ, Known Issues, and Command Summary sections.
  • Developer Guide: Wrote the overall structure/backbone, and the full contents of the Acknowledgements, Setting Up, Architecture (including the Architecture Diagram and Sequence Diagram), VFS Component (including VFS Class Diagram), and VFS Environment Persistence (including Save/Load Sequence Diagram) sections. Also contributed to Product Scope, User Stories, Non-Functional Requirements, Glossary, and Instructions for Manual Testing.
• Team-based tasks:
  • Coordinated team meetings and task distribution.
  • Created and managed GitHub issues and milestones for v1.0 and v2.0.
  • Reviewed PRs with substantive comments: #26, #90, #91, #94.