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<img src=".github/bashrs-hero.svg" alt="bashrs" width="800">
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<h1 align="center">Rash - Bidirectional Shell Safety Tool</h1>
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<a href="https://crates.io/crates/bashrs"><img src="https://img.shields.io/crates/v/bashrs.svg" alt="Crates.io"></a>
<a href="https://docs.rs/bashrs"><img src="https://docs.rs/bashrs/badge.svg" alt="Documentation"></a>
<a href="https://paiml.github.io/bashrs/"><img src="https://img.shields.io/badge/book-The%20Rash%20Book-blue" alt="Book"></a>
<a href="LICENSE"><img src="https://img.shields.io/crates/l/bashrs.svg" alt="License"></a>
<a href="https://github.com/paiml/bashrs/actions"><img src="https://github.com/paiml/bashrs/workflows/CI/badge.svg" alt="CI"></a>
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<b>Bidirectional shell safety tool that purifies legacy bash scripts and lets you write shell scripts in REAL Rust with automatic safety guarantees.</b>
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## Table of Contents
- [What's New](#-whats-new-in-v6490)
- [Why Rash?](#why-rash)
- [Quick Start](#quick-start)
- [Features](#features)
- [Core Commands](#core-commands)
- [Advanced Testing](#advanced-testing)
- [Documentation](#-documentation)
- [Quality Metrics](#quality-metrics)
- [Shell Compatibility](#shell-compatibility)
- [Performance](#performance)
- [MCP Server](#mcp-server)
- [Contributing](#contributing)
- [License](#license)
## 🚀 What's New in v6.50.0
**Latest Release** - 2026-01-06
- **Logic Extraction for EXTREME TDD**: Pure logic functions extracted from linter rules
- `sc2086_logic.rs`: Double-quote detection (37 unit tests)
- `sc2154_logic.rs`: Variable reference validation (44 unit tests)
- `devcontainer_logic.rs`: JSON validation helpers (42 unit tests)
- `sec010_logic.rs`: Path traversal detection (26 unit tests)
- **New Linter Rules**: docker007-012, signal001, systemd001, launchd001
- **Fast Coverage**: `make coverage` runs in under 5 minutes with nextest
- **Quality Metrics**: 9,824 tests, 94.16% line coverage, 96.52% function coverage
See [CHANGELOG.md](CHANGELOG.md) for complete release notes.
## Why Rash?
Shell scripts are everywhere—CI/CD pipelines, deployment automation, system configuration—but they're notoriously difficult to write safely. Rash solves this by providing:
1. **Bidirectional Safety**: Write in Rust and transpile to shell, or purify existing bash scripts
2. **Automatic Transformation**: Don't just detect problems—fix them automatically
3. **Deterministic Guarantees**: Same input always produces identical, reproducible output
4. **Zero Runtime Dependencies**: Generated scripts run on any POSIX-compliant system
## Features
- 🛡️ **Automatic Safety**: Protection against shell injection, word splitting, glob expansion
- 🔍 **Beyond Linting**: Full AST semantic understanding - **transforms** code, doesn't just warn
- 📦 **Zero Runtime Dependencies**: Generated scripts work on any POSIX shell
- 🎯 **Deterministic Output**: Same input always produces identical scripts
- ✅ **ShellCheck Compliant**: All output passes strict linting
### How Rash Exceeds ShellCheck
| ⚠️ **Warns**: "$RANDOM is non-deterministic" | ✅ **Rewrites** to version-based deterministic IDs |
| ⚠️ **Warns**: "mkdir may fail if exists" | ✅ **Transforms** to `mkdir -p` (idempotent) |
| ⚠️ **Warns**: "Unquoted variable expansion" | ✅ **Quotes** all variables automatically |
| Static pattern matching | **Full AST semantic understanding** |
| Detects issues (read-only) | **Fixes issues (read-write transformation)** |
**Key Difference**: ShellCheck tells you what's wrong. Rash **understands your code's intent** and rewrites it to be safe, deterministic, and idempotent — automatically.
## Quick Start
### Installation
```bash
# From crates.io (recommended)
cargo install bashrs
# Or from source
git clone https://github.com/paiml/bashrs
cd bashrs
cargo install --path rash
```
### Write Rust, Get Safe Shell
```rust
// install.rs
#[rash::main]
fn main() {
let version = env_var_or("VERSION", "1.0.0");
let prefix = env_var_or("PREFIX", "/usr/local");
echo("Installing MyApp {version} to {prefix}");
mkdir_p("{prefix}/bin");
mkdir_p("{prefix}/share/myapp");
if exec("cp myapp {prefix}/bin/") {
echo("✓ Binary installed");
} else {
eprint("✗ Failed to install binary");
exit(1);
}
}
```
**Transpile to safe POSIX shell**:
```bash
$ bashrs build install.rs -o install.sh
```
### Or Purify Existing Bash
**Before** (messy bash):
```bash
#!/bin/bash
SESSION_ID=$RANDOM # Non-deterministic
mkdir /app/releases/$RELEASE # Non-idempotent
rm /app/current # Fails if doesn't exist
```
**After** (purified by Rash):
```bash
#!/bin/sh
session_id="session-${version}" # ✅ Deterministic
mkdir -p "/app/releases/${release}" # ✅ Idempotent
rm -f "/app/current" # ✅ Safe removal
```
## Core Commands
```bash
# Transpile Rust to shell
bashrs build input.rs -o output.sh
# Purify legacy bash scripts
bashrs purify messy.sh -o clean.sh
# Interactive REPL with debugging
bashrs repl
# Lint shell scripts (including Dockerfiles)
bashrs lint script.sh
# Test bash scripts
bashrs test script.sh
# Quality scoring
bashrs score script.sh
# Comprehensive audit
bashrs audit script.sh
```
## Advanced Testing
Rash includes Probar integration for comprehensive quality assurance:
```bash
# State machine testing with playbooks
bashrs playbook install.playbook.yaml --run
# Mutation testing (goal: >90% kill rate)
bashrs mutate script.sh --count 10
# Deterministic simulation replay
bashrs simulate script.sh --seed 42 --verify
```
**Mutation Operators**: Rash applies 10 mutation operators including string mutations, command substitutions, conditional inversions, and redirect modifications to verify test quality.
## 📚 Documentation
**The Rash Book** is the canonical source for all documentation:
### [**→ Read The Rash Book**](https://paiml.github.io/bashrs/)
**Quick links**:
- [Getting Started](https://paiml.github.io/bashrs/getting-started/installation.html)
- [Quick Start Tutorial](https://paiml.github.io/bashrs/getting-started/quick-start.html)
- [Linting Rules](https://paiml.github.io/bashrs/linting/security.html)
- [Configuration Management](https://paiml.github.io/bashrs/config/overview.html)
- [API Reference](https://docs.rs/bashrs)
**Why the book?**
- ✅ All examples automatically tested
- ✅ Always up-to-date with latest release
- ✅ Comprehensive coverage of all features
- ✅ Real-world examples and tutorials
## Quality Metrics
| **PMAT Score** | 133/134 (99.3%) | ✅ Grade A+ |
| **Tests** | 9,824 passing | ✅ 100% pass rate |
| **Line Coverage** | 94.16% | ✅ Near target (95%) |
| **Function Coverage** | 96.52% | ✅ Exceeds target |
| **T-code Falsification** | 142/142 | ✅ 130-point checklist |
| **D-code Falsification** | 31/31 | ✅ Dockerfile validation |
| **ShellCheck** | 100% compliant | ✅ All output passes |
| **Shell Compatibility** | 6 shells | ✅ sh, dash, bash, ash, zsh, mksh |
### Falsification Testing (Popper Methodology)
Rash uses Popperian falsification—tests attempt to **disprove** functionality rather than prove it works:
```bash
# Run 130-point transpiler falsification checklist
cargo test -p bashrs --test transpiler_tcode_tests
# Run 30-point Dockerfile falsification checklist
cargo test -p bashrs --test dockerfile_dcode_tests
```
A passing test means the falsification attempt **failed**—the feature works correctly.
## Shell Compatibility
Generated scripts are tested on:
| POSIX sh | - | ✅ Full support |
| dash | 0.5.11+ | ✅ Full support |
| bash | 3.2+ | ✅ Full support |
| ash (BusyBox) | 1.30+ | ✅ Full support |
| zsh | 5.0+ | ✅ Full support |
| mksh | R59+ | ✅ Full support |
## Performance
Rash is designed for fast transpilation:
- **Rust-to-Shell**: 21.1µs transpile time
- **Makefile Parsing**: 0.034-1.43ms (70-320x faster than targets)
- **Memory Usage**: <10MB for most scripts
## MCP Server
Rash provides a Model Context Protocol (MCP) server for AI-assisted shell script generation:
```bash
# Install MCP server
cargo install rash-mcp
# Run server
rash-mcp
```
Available in the official MCP registry as `io.github.paiml/rash`.
## Contributing
We welcome contributions! See our [Contributing Guide](CONTRIBUTING.md) for details.
```bash
# Clone and test
git clone https://github.com/paiml/bashrs.git
cd bashrs
make test
# Run all quality checks
make validate
```
## License
MIT License. See [LICENSE](LICENSE) for details.
---
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<b>For comprehensive documentation, visit <a href="https://paiml.github.io/bashrs/">The Rash Book</a></b>
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