minishell — UNIX Shell in C

42 Urduliz — Common Core project

A fully functional UNIX command-line interpreter built from scratch in C, replicating the core behavior of bash.

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Features

• Command execution: absolute path, relative path, and PATH-based lookup
• Built-ins: echo, cd, pwd, export, unset, env, exit
• Pipes: multi-stage pipelines (cmd1 | cmd2 | cmd3)
• Redirections: <, >, >>, << (heredoc)
• Environment variables: full $VAR expansion and $? exit status
• Signal handling: Ctrl+C, Ctrl+D, Ctrl+\ behave as in bash
• Quote handling: single and double quotes with correct expansion rules

Build & Run

make
./minishell

Project Structure

minishell/
├── main/
│   ├── minishell.c     # Entry point, REPL loop
│   └── signals.c       # Signal handlers
├── parsing/            # Lexer and token tree builder
├── token/              # Token type handling
├── exec/               # Command execution, pipes, redirections
├── builtins/           # Built-in command implementations
├── libft/              # Custom C library
├── minishell.h         # Shared header
└── Makefile

Technical Highlights

Execution	fork() / execve() / waitpid()
Pipes	pipe() + file descriptor management
Signals	sigaction() — context-aware handling
Memory	No leaks on all paths (Valgrind verified)

Skills

C Process Management UNIX Signals Pipes Memory Management Parsing Linux

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Academic Integrity

This repository is shared for educational and portfolio purposes only.

For 42 students:

• Do not copy this code for your own project submissions
• Use it as a reference to understand concepts and approaches
• Write your own original solution — that is the only way to actually learn

42's core values are learning through practice, peer collaboration, and genuine problem-solving.

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License

MIT — see LICENSE for details. Copyright (c) 2026 Eneko Muñoz Bordona