🐚 Custom Unix Shell

A robust, modular Unix shell implementation in C. This project simulates a professional terminal environment, handling command-line parsing, process lifecycle management, and complex operator logic.

🎯 Project Overview

This shell was developed to explore low-level systems programming. It bridges the gap between user input and the Linux Kernel by utilizing system calls to manage processes and file descriptors.

Key Features

• Standard Command Execution: Runs all system binaries (e.g., ls, grep, vim, cat).
• Piping (|): Implements Inter-Process Communication (IPC) by connecting the stdout of one process to the stdin of another.
• I/O Redirection: Supports input redirection (<), output redirection (>), and appending (>>).
• Logical Operators: Handles conditional execution sequences using && (AND) and || (OR).

---

🏗️ Architecture & File Structure

The project is built with a modular "Separation of Concerns" approach:

.
├── include/        # Header files (.h) defining data structures and prototypes
├── src/            # Core logic implementation (.c)
│   ├── tokens.c    # Lexical analysis (breaking input into words)
│   ├── parser.c    # Syntax analysis (identifying pipes and redirects)
│   ├── exec.c      # Process management (fork, exec, wait)
│   └── alias.c     # Alias mapping and lookup logic
├── utils/          # Shared helper functions for string and memory safety
└── main/           # Entry point and REPL loop