Minishell – Unix Shell Implementation (42 Vienna)

This project is a custom implementation of a Unix shell, developed as part of the 42 Vienna curriculum. It focuses on low-level process management, parsing, file descriptor handling, and signal control.

The goal is to reproduce core shell behavior while maintaining correctness, robustness, and predictable resource handling.

Scope

• Command parsing and tokenization
• Process creation and management (fork, execve, wait)
• Pipes and redirections
• Environment variable expansion
• Built-in commands (cd, echo, pwd, export, unset, env, exit)
• Signal handling (SIGINT, SIGQUIT)
• Exit status propagation

Technical Focus

This project works directly with fundamental Unix primitives:

• Processes – lifecycle control, parent/child coordination, exit codes
• File descriptors – redirections, pipes, and I/O flow control
• Signals – interactive behavior, interruption handling, and cleanup
• Memory management – dynamic allocation and cleanup paths
• Parsing – transforming raw input into executable structures

The implementation prioritizes:

• correct resource management
• clear execution flow
• predictable behavior under error conditions

Security Relevance

Although not a security tool, minishell touches multiple areas relevant to defensive work:

• process isolation and execution context
• controlled environment variable handling
• input parsing and validation
• predictable signal behavior
• avoidance of descriptor leaks and orphaned processes

These are foundational concepts for understanding how real systems behave under normal and abnormal conditions.

Contents

• src/ – core implementation
• inc/ – headers and interfaces
• libft/ – supporting library (if included)
• Makefile – build logic

Notes

This repository is a curated snapshot of the project intended to demonstrate systems-level understanding and implementation quality. It is not intended as a drop-in replacement for a production shell.