0-shell 🐚

A simple Unix shell implemented from scratch in Rust.

0-shell (internally named minishel) is a project that dives deep into how shells really work — from process creation and signal handling to I/O redirection and piping. Built entirely in Rust for memory safety and performance.

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Table of Contents

• About
• Features
• Tech Stack
• Project Structure
• Getting Started
  • Prerequisites
  • Build
  • Run
• Built-in Commands
• Usage Examples
• Contributing
• License

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About

This project involves designing and implementing a simple shell (command-line interpreter) from scratch. The goal is to gain a deep understanding of:

• How shells parse and execute commands
• How processes are created and managed (fork / exec)
• How I/O redirection (>, <, >>) works under the hood
• How pipes (|) chain commands together
• How built-in commands differ from external binaries

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Features

• Interactive REPL prompt with username and current directory display
• Command execution (external binaries from $PATH)
• Pipes — chain multiple commands: cmd1 | cmd2 | cmd3
• I/O redirection — >, <, >>
• Built-in commands (cd, echo, exit, pwd, env, etc.)
• Signal handling (Ctrl+C, Ctrl+D)
• Terminal control via crossterm for a clean interactive experience

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Tech Stack

Tool	Purpose
Rust	Core language — memory safe, no GC
crossterm	Cross-platform terminal manipulation
users	Fetch current user info for the prompt
chrono	Date/time support
tempfile	Temporary files for pipe/redirection handling

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Project Structure

0-shell/
├── src/               # All Rust source files
│   └── main.rs        # Entry point
├── Cargo.toml         # Rust project manifest & dependencies
└── .gitignore

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Getting Started

Prerequisites

• Rust (edition 2024, via rustup)

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Build

git clone https://github.com/helbadaou/0-shell.git
cd 0-shell
cargo build --release

The compiled binary will be at:

target/release/minishel

Run

cargo run

Or run the compiled binary directly:

./target/release/minishel

You'll be greeted with an interactive prompt:

user@hostname:~$ 

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Built-in Commands

Command	Description
cd [dir]	Change the current directory
pwd	Print the current working directory
echo [args]	Print arguments to stdout
env	Display environment variables
export VAR=val	Set an environment variable
unset VAR	Unset an environment variable
exit [code]	Exit the shell with an optional code

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Usage Examples

# Run a simple command
$ ls -la

# Pipe commands
$ ls -la | grep ".rs" | wc -l

# Redirect output to a file
$ echo "hello world" > output.txt

# Append to a file
$ echo "another line" >> output.txt

# Read input from a file
$ cat < output.txt

# Combine pipes and redirections
$ cat < input.txt | grep "pattern" > result.txt

# Change directory
$ cd /tmp && pwd

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Contributing

1. Fork the repository
2. Create a feature branch: git checkout -b feat/your-feature
3. Commit your changes: git commit -m "feat: describe your change"
4. Push and open a Pull Request

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License

This project is open source. See LICENSE for details.

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Built with 🦀 Rust — because every great shell deserves a great language.