Simple Shell Project

Introduction

The Simple Shell project is one of the most challenging and rewarding tasks in the ALX SE program. It tests your understanding of:

• Programming fundamentals
• C language basics
• Engineering problem-solving skills
• Group collaboration
• Learning how to learn effectively

This project is designed to help you understand the internal workings of a UNIX shell and solidify your problem-solving approach.

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Important Notes

Learning Framework

Before starting, ensure you are familiar with the Learning Framework. Key takeaways include:

• Never copy code or solutions.
• Write code from scratch to demonstrate understanding.
• Use AI tools like ChatGPT appropriately, avoiding reliance on them for solutions.

Group Work Guidelines

This is a group project, requiring collaboration and accountability:

• Both partners must contribute equally.
• Review and understand all code pushed to the repository.
• Report any inability to contribute promptly to staff and your partner.

Plagiarism

Plagiarism will result in removal from the program. This includes:

• Copying code from others.
• Sharing solutions with peers.
• Publishing project content.

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Resources

• Unix Shell Overview
• Ken Thompson and the Thompson Shell
• Command documentation (man pages):
  • sh, access, execve, fork, wait, exit, etc.

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Learning Objectives

By completing this project, you should be able to explain:

• The origins of the UNIX operating system and shell.
• The roles of Ken Thompson and the B programming language.
• How a shell works, including processes, system calls, and PATH resolution.
• How to implement key shell functionalities (e.g., execve, fork, wait).

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Requirements

General

• All files will be compiled on Ubuntu 20.04 LTS with gcc:

  gcc -Wall -Werror -Wextra -pedantic -std=gnu89 *.c -o hsh
  
  

Use the Betty coding style. No memory leaks allowed. Include guards in all header files.ompilation To compile the shell:

gcc -Wall -Werror -Wextra -pedantic -std=gnu89 *.c -o hsh

Usage Interactive Mode

$ ./hsh

($) /bin/ls

hsh main.c shell.c

($) exit

$

Non-Interactive Mode

$ echo "/bin/ls" | ./hsh hsh main.c shell.c

$ $ cat test_ls | ./hsh

hsh main.c shell.c

hsh main.c shell.c $

Tasks Mandatory Tasks Betty Checks: Ensure code passes the Betty linter. Simple Shell 0.1:

Implement a simple UNIX command-line interpreter. Display a prompt and execute commands using execve. Simple Shell 0.2:

Enhance the shell to support argument parsing. Additional tasks: Incrementally improve the shell to handle advanced features. Allowed Functions Key functions and system calls include:

execve, fork, wait, exit, _exit, malloc, free, getline, isatty, write, etc. Testing Run the shell in various modes and scenarios, including edge cases:

Use interactive and non-interactive modes. Test built-in commands and error handling. Functions are limited to 5 per file.