Minishell

As beautiful as a shell

Overview

Minishell is a project designed to create a simple, custom shell in C, closely mimicking the functionality of Bash. The project focuses on understanding processes, file descriptors, and various shell operations. This README provides a detailed guide on the structure, functionality, and usage of the Minishell project.

Table of Contents

1. Introduction
2. Features
3. Installation
4. Usage
5. Built-in Commands
6. Acknowledgments

Introduction

The existence of shells is linked to the very existence of IT. Initially, developers used aligned 1/0 switches to communicate with computers, which was quite cumbersome. The invention of shells allowed interactive command-line communication in a language closer to human language. With Minishell, we revisit the fundamental problems faced before modern GUIs and sophisticated shells like Bash.

Features

Minishell includes the following features:

• Display a prompt while waiting for a new command.
• Maintain a working history of commands.
• Search and execute the correct executable based on the PATH variable or using a relative/absolute path.
• Handle single and double quotes to manage metacharacters.
• Implement input (<), output (>), append (>>), and here-document (<<) redirections.
• Support pipes (|) to connect the output of one command to the input of another.
• Manage environment variables and special parameter $? for the exit status of the most recently executed foreground pipeline.
• Handle ctrl-C, ctrl-D, and ctrl-\ signals as in Bash.
• Built-in commands: echo, cd, pwd, export, unset, env, and exit.

Installation

To install and run Minishell, follow these steps:

1. Clone the Repository

   git clone <repository-url>
   cd minishell

2. Build the Project

   make

3. Run Minishell

   ./minishell

Usage

Once Minishell is running, you can use it similarly to Bash:

• Basic Commands

  ls -l
  echo "Hello, World!"

• Redirections

  cat < input.txt
  echo "New content" > output.txt
  echo "Append this" >> output.txt
  cat << EOF
  > This is a
  > here-document example
  > EOF

• Pipes

  ls -l | grep minishell

• Environment Variables

  echo $HOME
  echo $?

• Signal Handling

  • ctrl-C: Displays a new prompt on a new line.
  • ctrl-D: Exits the shell.
  • ctrl-\: Does nothing.

Built-in Commands

Minishell implements several built-in commands:

• echo

  echo -n "No newline"

• cd

  cd /path/to/directory

• pwd

  pwd

• export

  export VAR=value

• unset

  unset VAR

• env

  env

• exit

  exit