/simple_shell

This is an ALX team project on Simple Shell.

Primary LanguageCThe UnlicenseUnlicense

Simple Shell Project

alt text

Table of Contents

About

The shell is a command-line interface ( a program) that provides a user interface to interact with an operating system's kernel or execute commands. The shell acts as a bridge between the user and the operating system. This project is a simple implementation of a shell in C. It illustrates how the shell works i.e. read, parse, fork, exec and wait. It is limited in functions as it is built to only meet the requirements given by ALX.

Objectives

  • Develop a custom simple shell that emulates the functionality of the original shell.
  • Deepen your understanding of the C-programming language and Shell.
  • What is a pid and a ppid?
  • How to manipulate the environment of the current process
  • Difference between a function and a system call
  • How to create processes
  • Know the three prototypes of main
  • How the shell uses PATH to find programs.
  • How to execute another program with the execve system call
  • How to suspend the execution of a process until one of its children terminates
  • What is EOF / “end-of-file”?

Features

List of allowed functions and system calls

  • access (man 2 access)
  • chdir (man 2 chdir)
  • close (man 2 close)
  • closedir (man 3 closedir)
  • execve (man 2 execve)
  • exit (man 3 exit)
  • _exit (man 2 _exit)
  • fflush (man 3 fflush)
  • fork (man 2 fork)
  • free (man 3 free)
  • getcwd (man 3 getcwd)
  • getline (man 3 getline)
  • getpid (man 2 getpid)
  • isatty (man 3 isatty)
  • kill (man 2 kill)
  • malloc (man 3 malloc)
  • open (man 2 open)
  • opendir (man 3 opendir)
  • perror (man 3 perror)
  • read (man 2 read)
  • readdir (man 3 readdir)
  • signal (man 2 signal)
  • stat (__xstat) (man 2 stat)
  • lstat (__lxstat) (man 2 lstat)
  • fstat (__fxstat) (man 2 fstat)
  • strtok (man 3 strtok)
  • wait (man 2 wait)
  • waitpid (man 2 waitpid)
  • wait3 (man 2 wait3)
  • wait4 (man 2 wait4)
  • write (man 2 write)

Prerequisites

The only prerequisite is to clone this repo. However, you need a good understanding of the following:

  • [Pointers & Arrays]
  • [Structures & Typedef]
  • [Function Pointers]
  • [Command-line arguments (Argv & Argc)]
  • [Dynamic Memory Allocation (Malloc)]
  • [Process Identifier (PID) & Parent Process Identifier (PPID)]
  • [fork()]
  • [execve()]
  • [wait()]
  • [getline()]
  • [strtok]

Installation

  1. Clone the repository:

     https://github.com/Huclark/simple_shell.git

  2. Use gcc -Wall -Werror -Wextra -pedantic -std=gnu89 *.c -o hsh to compile.

  3. Use ./hsh to run.

Limitations

This is a school project and it is built to meet the requirements of the project. It has many limitations including:

  • Only built-ins are cd, exit, env.

Contributions

This is a team project with the following contributors:

Since this is a team project for ALX SE Progamme, we won't be accepting any pull requests. However, please feel free to make or suggest any changes that would make the whole code run better. See AUTHORS for our emails to reach us.

License

This code is in the public domain (see UNLICENSE for more details). This means you can use, modify, and distribute it without any restriction. We appreciate, but don't require, acknowledgement in derivative works.