Welcome to Minishell! This project aims to create a mini version of a Unix shell, providing an educational and practical experience on the internal workings of a shell.

• Introduction
• Features
• Installation
• Usage
• Built-in Commands
• Bonus Features
• Technical Details

Minishell is a simple shell implementation inspired by the basic functionalities of Unix shells like bash. The goal is to provide a minimalist environment to execute commands, handle redirections, and more.

Minishell includes the following features:

• Display a prompt waiting for a command.
• Command history management.
• Execute commands based on the PATH variable or by specifying a relative/absolute path.
• Handle single and double quotes, environment variables, and special characters.
• Implement input/output redirections and pipelines.
• Basic built-in commands like echo, cd, pwd, export, unset, env, and exit.
• Signal handling for Ctrl+C, Ctrl+D, and Ctrl+\ as in bash.

To install and run Minishell on your machine, follow these steps:

1. Clone the repository:

   git clone https://github.com/pepedinho/minishell.git
   cd minishell

2. compile the project:

     make

3. Run the shell:

     ./minishell

If you have Docker and Docker Compose installed, you can quickly test Minishell in an optimal environment by running:

make docker

Once you have compiled and launched Minishell, you will see a prompt similar to this:

user:/home/user$

You can start typing commands just like in a Unix shell. For example:

user:/home/user$ echo "Hello, world!"
Hello, world!

Minishell supports the following built-in commands:

• echo: Prints text to the terminal. Supports the -n option to omit the trailing newline.
• cd: Changes the current directory.
• pwd: Prints the current working directory.
• export: Sets environment variables.
• unset: Unsets environment variables.
• env: Displays the current environment variables.
• exit: Exits the shell.

Minishell supports the following redirection operators:

• <: Redirects input.
• >: Redirects output (overwrite).
• >>: Redirects output (append).
• <<: Here document, where input is read until a delimiter is encountered.

Pipelines are supported via the | character, allowing you to chain commands by passing the output of one command as input to the next.

• Ctrl+C: Interrupts the current command and displays a new prompt.
• Ctrl+D: Exits the shell.
• Ctrl+\: Does nothing, matching bash behavior.

Minishell also includes features like:

• Logical operators && and || for chaining commands with support for parentheses.
• Wildcard support (*) for pattern matching in the current working directory.

• Abstract Syntax Tree (AST): Minishell uses a binary tree-based AST to parse and organize commands. This structure is crucial for handling complex command sequences, like pipes and redirections, by ensuring the correct execution order and simplifying the parsing process.

• Garbage Collector: A custom garbage collector is implemented to manage dynamic memory allocation, preventing leaks. This is essential for maintaining performance and stability, especially as the shell processes multiple commands and builds the AST dynamically.