MiniShell

A lightweight, POSIX-compliant command-line shell written in C, featuring advanced parsing, redirections, wildcard expansion, and more.

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Table of Contents

• Introduction
• Advanced Features
• Installation
• Configuration
• Usage
• License

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Introduction

MiniShell is a custom command-line interpreter designed to mimic the behavior of popular shells (bash, zsh) while introducing robust internal mechanisms such as garbage-collected memory management, detailed debug output, and a modular architecture for easy extension.

Advanced Features

1. Comprehensive Parsing Engine

• Tokenization & AST Construction: Supports quotes (', "), command substitution $(cmd), and logical operators (&&, ||, |).
• Wildcard Expansion: Implements * and ? expsansion within arguments, searching directories recursively.

2. Redirections & Here-Documents

• Input/Output Redirections: <, >, >>, <>.
• Here-Document (<<): Inline multi-line input with proper variable expansion support.

3. Built-in Commands

• cd, export, unset, env, pwd, echo, exit with POSIX-compatible flags and error handling.

4. Environment Management

• Dynamic Hashmap: Efficient and fast name-value storage for environment variables, automatically resizing.
• Persistent State: Updates SHLVL, PWD, and OLDPWD seamlessly.

5. Signal Handling & Job Control

• Context-aware signal setup for prompt, heredoc, and child processes to ensure a smooth user experience.

6. Memory Safety & Garbage Collector

• Custom GC: Tracks allocations and automatically frees unused memory at end-of-execution or on errors.
• Prevents leaks and dangling pointers, even in complex pipelines.

7. Debugging Utilities

• Toggleable debug levels to inspect token lists, AST nodes, and command execution states for rapid development and troubleshooting.

Installation

git clone https://github.com/yourusername/minishell.git
cd minishell
make

Configuration

• Debugging: Set DEBUG in debug.h to desired level (0–13).

• Shell Name: Customize the shell’s displayed name by editing the MINISHELL_NAME macro in header.h.

• Prompt: Define a custom prompt format using the PROMPT macro in minishell.h.

• Welcome Prompt: Customize the welcome message displayed at shell startup by modifying the MINISHELL_WELCOME_START and MINISHELL_WELCOME_END macros in minishell.h.

• Builtin Command Names: Rename built-in commands by modifying the BUILTIN_<CMD>_NAME macros in builtins.h.

• Signal Display: Enable or disable signal reporting by setting MINISHELL_SHOW_SIGNALS in minishell.h (0 disables, 1 enables).

• Core Dump on Signal: Control core dump message via the SIGNAL_CORE_DUMP_MESSAGE macro in minishell_signal.h.

Note: After adjusting any configuration macros in headers run make clean && make to recompile and apply your changes or directly run make CONFIGURATION=-D<DEFINE>=<VALUE>.

Usage

Launch the shell interactively:

./minishell

Run a script:

./minishell script.sh

Execute single command:

./minishell -c "echo Hello World"

License

Distributed under the MIT License. See LICENSE for details.