Minishell

A simple shell implementation inspired by bash, developed as part of the 42 School curriculum.

📝 About

Minishell is a simplified shell that implements basic functionality similar to bash. This project challenges students to understand how shells work, process management, and file descriptors while building a functional command-line interpreter.

✨ Features

• Display a prompt while waiting for a new command
• Working history management
• Search and execute commands based on PATH variable or using relative/absolute path
• Handle quotes (' and ") and special characters
• Implement redirections (<, >, <<, >>)
• Implement pipes (|)
• Handle environment variables ($ followed by characters)
• Handle $? which expands to the exit status
• Handle signals (ctrl-C, ctrl-D, ctrl-\)

Built-in Commands

• echo with option -n
• cd with relative or absolute path
• pwd without any options
• export without any options
• unset without any options
• env without any options
• exit without any options

🛠️ Installation

# Clone the repository
git clone https://github.com/NzolaKiampava/minishell.git

# Navigate to the project directory
cd minishell

# Compile the project
make

# Run minishell
./minishell

💻 Usage

# Basic command execution
$> ls -la

# Using pipes
$> ls | grep filename

# Input/Output redirections
$> echo "hello" > output.txt
$> cat < input.txt

# Environment variables
$> echo $PATH

# Built-in commands
$> cd ..
$> pwd
$> echo "Hello World"

⚙️ Project Structure

minishell/
├── Makefile
├── includes/
│   └── minishell.h
├── libft/
│   ├── Makefile
│   └── [libft source files]
├── src/
│   ├── main.c
│   ├── builtins/
│   │   ├── cd.c
│   │   ├── echo.c
│   │   ├── env.c
│   │   ├── exit.c
│   │   ├── export.c
│   │   ├── pwd.c
│   │   └── unset.c
│   ├── executor/
│   │   ├── executor.c
│   │   ├── pipe_handler.c
│   │   └── redirections.c
│   ├── parser/
│   │   ├── parser.c
│   │   ├── tokenizer.c
│   │   └── expander.c
│   ├── signals/
│   │   └── signals.c
│   └── utils/
│       ├── environment.c
│       └── error_handler.c

Component Description

1. Builtins (src/builtins/)

   • Implementation of all required shell built-in commands
   • Each command in a separate file for better organization

2. Executor (src/executor/)

   • executor.c: Main command execution logic
   • pipe_handler.c: Handles pipe operations between commands
   • redirections.c: Manages input/output redirections

3. Parser (src/parser/)

   • parser.c: Command line parsing and structure creation
   • tokenizer.c: Splits input into tokens
   • expander.c: Handles environment variable expansion

4. Signals (src/signals/)

   • signals.c: Handles all signal-related functionality

5. Utils (src/utils/)

   • environment.c: Environment variable management
   • error_handler.c: Error handling and messaging

🔍 Testing

The shell has been tested with:

• Basic command execution
• Complex pipe sequences
• Various types of redirections
• Edge cases with quotes and special characters
• Memory leak checks using Valgrind
• Error handling scenarios

⚠️ Known Limitations

• Does not handle advanced features like wildcards (*)
• No command history file persistence between sessions
• Limited signal handling compared to bash

📚 Resources

• Bash Reference Manual
• Writing Your Own Shell

👥 Contributors

• Nzola Kiampava
• Manuel de Almeida

📝 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• 42 School for the challenging project
• Fellow 42 students for testing and feedback
• The open-source community for valuable resources