42-Minishell

Minishell ⬇

You can watch a demonstration of the Minishell in action here: Minishell Video

Download Minishell Video

Project Overview

Minishell is a shell application that simulates command-line functionality in a UNIX-like terminal environment. The project aims to replicate the core functionalities of modern shells by adopting a modular approach to various functionalities. It includes command processing, environment variable management, and the implementation of various shell features.

Features

• Basic Shell Functionality:

  • Displays a prompt while waiting for a new command from the user.
  • Manages command history.
  • Finds and executes the correct executable file based on the PATH variable or using absolute/relative paths.

• Redirections:

  • < redirects input.
  • > redirects output.
  • << reads input until a line containing the delimiter is found, but does not update the history.
  • >> redirects output in append mode.

• Pipes:

  • Handles pipes (|) by connecting the output of each command in the pipeline to the input of the next.

• Quoting:

  • Handles single quotes (') and double quotes ("). Double quotes prevent the shell from interpreting metacharacters in the quoted sequence, except for the $ (dollar sign) character.

• Environment Variables & Special Variables:

  • Expands environment variables prefixed with $.
  • Expands $? to the exit status of the most recently executed foreground pipeline.

• User Interactions:

  • ctrl-C displays a new prompt on a new line.
  • ctrl-D exits the shell.
  • ctrl-\ does nothing.

• Builtin Commands:

  • echo - with the -n option.
  • cd - with only a relative or absolute path.
  • pwd - with no options.
  • export - with no options.
  • unset - with no options.
  • env - with no options or arguments.
  • exit - with no options.

Folder Structure

• BUILTIN: Implementations of the builtin commands.
• ERROR: Error handling functions.
• EXECUTOR: Command execution logic.
• GNL: Line-by-line reading functionality.
• INCLUDES: Header files.
• LEXER: Functionality for tokenizing commands.
• PARSER: Command analysis and execution logic.
• UTILS: Utility functions and tools.
• Makefile: Rules for compiling the project.

Responsibilities and Tasks

Text Processing and Control (Parser)

• Text Parsing: Processing and structuring input from the command line into appropriate data structures. This includes separating commands, arguments, and redirections.
• Parser Control: Implementing control mechanisms to ensure the correctness of parser functions. This involves handling erroneous inputs or unexpected conditions.

Environment Variable Handling

• Environment Variable Management: Proper management and processing of user environment variables (e.g., PATH, HOME, PWD). This includes retrieving the values of these variables and integrating them into shell commands.
• Variable Substitution: Correctly processing and substituting environment variables within commands. This ensures that variables like $USER and $PWD are replaced with their actual values.

Signal Handling

• Signal Handling: Managing and processing signals for processes running within the shell. This includes handling signals sent by the user (e.g., SIGINT, SIGQUIT) and responding appropriately to these signals.

Functions Implemented by e-kose

Redirection Operations

• Description: Implementing output redirection (>, >>) and input redirection (<). This function allows the redirection of command outputs or inputs to files.

Heredoc Processing

• Description: Heredoc is used to handle multiline inputs within commands. The input provided by the user is read until a specified delimiter is encountered, and it is used as input for the command.

User Commands

• echo: Prints text to the screen. The -n option suppresses the newline character at the end of the output.
• cd: Changes the current directory. The directory can be changed using relative or absolute paths.
• pwd: Displays the current working directory.
• export: Defines environment variables and displays current environment variables.
• unset: Removes the specified environment variable from the environment.
• env: Lists environment variables and executes commands within this environment.
• exit: Exits the program.

Processing Executable Files

• Description: Processing executable files located under bin/. This function ensures that various executable files in the bin/ directory are correctly processed and executed.

Benefits of Group Work

Throughout this project, we learned the importance of effective collaboration and teamwork. Working in a group allowed us to divide tasks according to each member's strengths, leading to a more efficient development process. Each member contributed their expertise, enhancing the quality and functionality of the final product. A special thank you to e-kose for their invaluable contributions and collaboration.

Installation Instructions

Clone the project to your computer:

git clone https://github.com/menasy/42-Minishell.git
cd minishell

Run The Project

make
./minishell