Minishell

Introduction

Minishell is a simple shell implementation project. It aims to provide a basic command-line interface similar to Bash, where users can execute commands, handle file redirection, pipelines, environment variables, and manage signals.

Features

The mandatory part of this project implements the following core functionalities:

1. Prompt: Displays a prompt when waiting for a new command.
2. Command History: Maintains a history of previously executed commands.
3. Executable Search: Finds and executes commands based on the PATH environment variable, or using relative/absolute paths.
4. Global Variables: Minimizes the use of global variables, with one allowed for signaling.
5. Quotes Handling:
   • Single quotes (') prevent interpretation of special characters.
   • Double quotes (") prevent interpretation of special characters, except for $.
6. Redirections:
   • <: Redirect input.
   • >: Redirect output.
   • <<: Implements here-document functionality.
   • >>: Redirect output in append mode.
7. Pipes (|): Supports piping where the output of one command is used as the input to the next.
8. Environment Variables: Handles $ for variable expansion and $$ for the exit status of the most recently executed foreground pipeline.
9. Signal Handling:
   • Ctrl-C: Interrupts and shows a new prompt.
   • Ctrl-D: Exits the shell.
   • Ctrl-\: Does nothing.
10. Built-in Commands:
    • echo with the -n option.
    • cd with relative or absolute paths.
    • pwd to print the working directory.
    • export for managing environment variables.
    • unset for removing environment variables.
    • env to display the current environment variables.
    • exit to close the shell.

Requirements

• C Language: The project is written in C and adheres to the 42 Norm.
• Memory Management: All allocated memory is freed when necessary; no leaks are tolerated except those from the readline() function.
• Makefile: A Makefile is included to compile the project using the flags -Wall -Wextra -Werror without relinking. The rules include:
  • all: Compiles the program.
  • clean: Removes object files.
  • fclean: Removes all generated files.
  • re: Rebuilds the project.

Usage

To compile the project:

make

To run the shell:

./minishell

Reference

• Bash Manual

Leaks

valgrind --leak-check=full -q ./minishell