Dose - DOS-Style Command Shell

Dose is a DOS-style command shell implementation written in Zig. Originally started in Rust, the project has been completely rewritten in Zig to provide a nostalgic DOS computing experience with modern systems programming capabilities.

This project faithfully reproduces classic MS-DOS command behaviors, syntax, and error messages while running on modern systems.

Features

Interactive REPL Shell

DOS-style command prompt (C:\PATH>)
Complete lexer/parser for DOS command syntax with quote support
Authentic DOS behavior and error messages

Built-in Commands

Core File Operations: - COPY - File copying with overwrite prompts and device handling - DIR - Directory listing with file sizes, counts, and free space display - TYPE - Display file contents with binary character filtering - CD/CHDIR - Directory navigation with path validation

Extended File Operations: - MD/MKDIR - Directory creation with nested path support - RD/RMDIR - Directory removal with safety checks - REN/RENAME - File and directory renaming - DEL/REMOVE - File deletion with wildcard support - PATH - Environment PATH variable management (GET/SET) - MOVE - File/directory moving (placeholder)

Shell and System Commands: - ECHO (with ON/OFF variants) - Text output and echo state control - CLS - Clear screen with ANSI escape sequences - EXIT - Exit the shell - VER - Version information display - DATE - Current system date with proper calendar calculations - TIME - Current system time display - SORT - Alphabetical line sorting with input redirection support

I/O Redirection System

Input redirection (<): Read file content as command input
Output redirection (>): Write command output to file (overwrite)
Append redirection (>>): Append command output to file
Combined redirection: Support for both input and output redirection simultaneously
Device handling: Proper CON/LPT/PRN device recognition and error handling

External Command Support

Full process spawning with I/O redirection support
Proper command-line argument handling
DOS-compatible "command not found" messages
Exit code propagation

Path Formatting

DOS-style path display with drive letters
8.3 filename conversion where applicable
Converts / to \ and uppercases drive letters and names
Defaults to C: when no drive is present

Technical Features

Memory Management

Allocator-based: Uses Zig's GeneralPurposeAllocator for all dynamic memory
RAII Pattern: Proper resource cleanup with defer statements
Leak Detection: Built-in memory leak detection in debug builds

Error Handling

Zig Error Unions: Native !T error handling instead of exceptions
DOS-Authentic Messages: Faithful reproduction of classic DOS error text
Graceful Degradation: Robust error recovery and user guidance

Architecture

Type-Safe Commands: Uses Zig unions and enums for command architecture
Modular Design: Clean separation between parsing, execution, and I/O
Zero Dependencies: Uses only Zig standard library
Cross-Platform: Portable file system and process operations

Build

Requirements: - Zig (recent version)

Commands:

# Development
zig build                 # Build debug version
zig build run             # Build and run in debug mode
zig build test            # Run unit tests
zig build -Doptimize=ReleaseFast  # Optimized build

This produces an executable in zig-out/bin/dose.

Run

Start the shell:

zig-out/bin/dose

You’ll see a DOS-like prompt. Example interactions:

C:\> VER
DOSE Version 6.22
C:\> DIR
... directory listing ...
C:\> COPY CON hello.txt
Hello world! 
^Z
 1 File(s) copied
C:\> TYPE hello.txt
Hello world!

Redirection:

C:\> DIR > dir.txt
C:\> TYPE dir.txt

Change directory:

C:\> CD ..
C:\> DIR

Project Structure

src/
├── cmd/                    # Modular command implementations
│   ├── lib/
│   │   └── types.zig      # Shared command types and interfaces
│   ├── chdir.zig          # CD/CHDIR command
│   ├── cls.zig            # CLS command  
│   ├── copy.zig           # COPY command
│   ├── date.zig           # DATE command
│   ├── dir.zig            # DIR command
│   ├── echo.zig           # ECHO command variants
│   ├── mkdir.zig          # MD/MKDIR command
│   ├── move.zig           # MOVE command (placeholder)
│   ├── path.zig           # PATH command (GET/SET)
│   ├── remove.zig         # DEL/REMOVE command
│   ├── rename.zig         # REN/RENAME command
│   ├── rmdir.zig          # RD/RMDIR command
│   ├── sort.zig           # SORT command
│   ├── time.zig           # TIME command
│   └── type.zig           # TYPE command
├── cmd.zig                # Command type definitions and imports
├── eval.zig               # Command execution engine
├── parser.zig             # DOS command line parser
├── paths.zig              # DOS path formatting utilities  
├── syntax.zig             # Command syntax structures
└── main.zig               # Application entry point and REPL

License

GNU AGPLv3.