🐚 Minishell

A minimalistic shell inspired by bash, built in C! This project is part of the 42 School curriculum, where we implement our own shell with fundamental UNIX features. 🚀

📝 What is Minishell?

Minishell is a small-scale Unix shell that mimics the behavior of Bash, implementing key functionalities of a command-line interpreter. It allows users to interact with the system by executing commands, handling input/output redirections, managing environment variables, and supporting pipes for command chaining.

The project focuses on understanding low-level system calls, process control, and memory management. Unlike a full-fledged shell like Bash or Zsh, Minishell is designed to provide a lightweight yet functional experience by implementing core features without unnecessary overhead.

🔍 Key Features & Objectives

✅ Command Execution – Supports running binaries from absolute, relative paths, and using the $PATH environment variable.
✅ Built-in Commands – Implements echo, cd, pwd, export, unset, env, and exit without external binaries.
✅ Pipelines (|) – Connects multiple commands where the output of one command becomes the input of another.
✅ Redirections (<, >, >>, <<) – Handles input and output redirections including here-doc (<<).
✅ Environment Variable Expansion ($VAR) – Supports substitution of environment variables like $HOME, $USER, etc.
✅ Exit Status ($?) – Stores the exit status of the last executed command.
✅ Signal Handling – Reacts to Ctrl+C (displays a new prompt), Ctrl+D (exits), and Ctrl+\ (ignored like in Bash).
✅ History Support – Saves and navigates through previously executed commands.
✅ Minimal Global Variables – Uses at most one global variable for signal handling, ensuring structured memory management.
✅ Error Handling – Properly manages invalid inputs, permission errors, and system call failures.

⚡ Installation

Make sure you have cc and readline installed on your system.

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

# Compile the shell
make

# Run the shell
./minishell

🚀 Usage

Once inside minishell, you can run commands just like in a normal shell:

$ ls -l
$ echo "Hello, World!"
$ pwd
$ export MY_VAR=42
$ echo $MY_VAR
$ cat file.txt | grep keyword
$ ls > output.txt

🔧 Built-in Commands

Command	Description
echo	Prints text to the terminal (supports -n option)
cd	Changes the current directory
pwd	Prints the current directory
export	Sets environment variables
unset	Removes environment variables
env	Prints all environment variables
exit	Exits the shell

📶 Signal Handling

Shortcut	Behavior
Ctrl + C	Stops the current process and displays a new prompt
Ctrl + D	Exits the shell
Ctrl + \	Does nothing (ignored like in Bash)

📂 Project Structure

minishell/
│── src/          # Source code files
│── include/      # Header files
│── Makefile      # Compilation rules
│── README.md

🛠 System Calls Used

• fork(), execve() → Process execution
• pipe(), dup2() → Handling pipes and redirections
• waitpid() → Managing child processes
• signal(), sigaction() → Handling signals

👨‍💻 Authors

• Izagini GitHub Profile
• paul42b GitHub Profile

🌟 Acknowledgments

Thanks to 42 School for this challenging project! 🎓