This project has been created as part of the 42 curriculumby pjelinek & abita.

🐚 Minishell

📖 Description

Minishell is an educational project from the 42 curriculum. Its goal is to implement a minimal Unix shell in C, recreating the core behavior of Bash in a simplified but technically accurate way.

The project focuses on understanding how a shell works internally, including process creation, file descriptor management, signal handling, and command parsing.

Minishell provides an interactive command-line interface that allows users to:

• Execute external programs
• Manage environment variables
• Use pipes and redirections
• Interact safely with the operating system

Rather than copying Bash feature-by-feature, the objective is to deeply understand low-level system programming concepts such as fork, execve, pipe, dup2, signals, and terminal control — while maintaining strict memory safety and robustness.

⚙️ Instructions

🔧 Compilation

The project is written in C and must be compiled using cc with the required flags

This generates the executable: make

📜 Makefile Rules

Command	Description
make / make all	Build the project
make clean	Remove object files
make fclean	Remove objects and executable
make re	Rebuild from scratch
make bonus	Build bonus features (if available)

---

▶️ Execution

Run Minishell with: $./minishell

The program will display a prompt and wait for user input.

🧠 Interactive Behavior

Shortcut	Behavior
Ctrl-C	Display a new prompt
Ctrl-D	Exit the shell
Ctrl-\	No action

🧩 Features

• Interactive prompt with command history

• Execution of external commands via PATH, relative or absolute paths

• Environment variable expansion ($VAR, $?)

• Quote handling ('single' and "double")

• Redirections:

  • Input <
  • Output >
  • Append >>
  • Heredoc <<

• Pipes (|)

• Bash-like signal behavior

• Built-in commands:

  • echo (with -n)
  • cd
  • pwd
  • export
  • unset
  • env
  • exit

📚 Resources

🔬 Technical References

• GNU Bash Manual [https://www.gnu.org/software/bash/manual/]

• Linux Man Pages:

  • man fork
  • man execve
  • man pipe
  • man dup2
  • man signal

• GNU Readline Documentation

These sources were used to validate shell behavior, system call semantics, and edge cases by comparing Minishell with Bash.

🤖 Use of AI Tools

AI tools were used responsibly during development in accordance with the 42 AI policy.

AI assistance was applied for:

• Clarifying system call behavior and edge cases
• Explaining shell internals (word splitting, pipelines, signals)
• Reviewing parsing strategies and data-structure concepts

No AI-generated code was integrated without manual review and validation. All core logic, parsing, execution flow, and memory management were designed and implemented manually.

The author takes full responsibility for all code and design decisions. Peer reviews and manual testing were the primary validation methods.