This project has been created as part of the 42 curriculum by gahubert, madelwau

Minishell

Description

Minishell is the first group project of the 42 curriculum. As suggested by it's name, the goal of this project is to write a minimalist implementation of a command-line interpreter inspired by Bash. The primary goal of this project is to explore the underlying mechanisms of process creation, lifecycle management, file descriptor manipulations, and signal handling within a Unix environment.

This implementation focuses exclusively on the mandatory requirements of the project, establishing a reliable, leak-free, and robust foundation for basic shell operations.

Core Features (Mandatory Part)

• Interactive Prompt: Displays a clean visual prompt while waiting for new command inputs.
• Command History: Full tracking and navigation of previously executed commands using the readline library history tools.
• System Execution: Dynamically searches, locates, and launches binaries using absolute paths, relative paths, or by scanning the system's PATH environment variable.
• Environment Variable Expansion: Seamlessly expands environment variables (e.g., $USER) and handles the specific $? variable to fetch the exit status of the latest foreground execution pipeline.
• Quote Handling:
  • Single quotes (') literalize every character contained inside them.
  • Double quotes (") literalize characters but retain the expansion properties of the $ token.
• Redirections:
  • Input redirection (<)
  • Output redirection (>) in overwrite mode
  • Append output redirection (>>)
  • Here-doc (<<) with a custom delimiter string (does not update command history).
• Pipelines (|): Connects the standard output of a command to the standard input of the next command sequentially using Unix pipes.
• Signal Handling: Replicating Bash's response layout to key interactive interrupts:
  • Ctrl-C: Displays a fresh prompt on a new line.
  • Ctrl-D: Cleanly exits the shell session.
  • Ctrl-\: Performs no action.
• Built-in Utilities: Custom native implementations of standard routines:
  • echo (supporting the -n option)
  • cd (accepting relative or absolute target paths)
  • pwd (with no options)
  • export (with no options)
  • unset (with no options)
  • env (with no arguments or options)
  • exit (with no options)

Instructions

Compilation

The project includes a Makefile configured to compile the source code using cc along with strict compiler warnings (-Wall -Wextra -Werror).

To compile the executable, run:

make

• make or make all: Compiles the core minishell executable.
• make clean: Removes intermediate object files (.o).
• make fclean: Clears object files along with the final minishell binary file.
• make re: Triggers a full clean re-compilation of the entire project scope.

Launching the Shell

Once compilation completes successfully, launch the shell interface directly from your system terminal:

./minishell

Ressources

• Introduction to Systems Programming: a Hands-on Approach

Ai Usage

AI was used during this project to speed up documentation research.