nneka-chukwuemeka/simple_shell

This repository contains the files for Alx simple_shell project. It can be compiled using GCC and will execute a simple shell that can be used for some basic tasks and programs most commonly found in the /bin/ folder.

Resources Read or watch:

Unix shell Thompson shell Ken Thompson Everything you need to know to start coding your own shell concept page man or help:

sh (Run sh as well) Learning Objectives At the end of this project, you are expected to be able to explain to anyone, without the help of Google:

General

Who designed and implemented the original Unix operating system Who wrote the first version of the UNIX shell Who invented the B programming language (the direct predecessor to the C programming language) Who is Ken Thompson How does a shell work What is a pid and a ppid How to manipulate the environment of the current process What is the difference between a function and a system call How to create processes What are the three prototypes of main How does the shell use the PATH to find the 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”?

Requirements

General Allowed editors: vi, vim, emacs All your files will be compiled on Ubuntu 20.04 LTS using gcc, using the options -Wall -Werror -Wextra -pedantic -std=gnu89 All your files should end with a new line A README.md file, at the root of the folder of the project is mandatory Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl Your shell should not have any memory leaks No more than 5 functions per file All your header files should be include guarded Use system calls only when you need to (why?) Write a README with the description of your project You should have an AUTHORS file at the root of your repository, listing all individuals having contributed content to the repository. Format, see Docker GitHub *There should be one project repository per group. If you and your partner have a repository with the same name in both your accounts, you risk a 0% score. Add your partner as a collaborator. *

Pre-requisites

Authorized functions and macros:

• 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)
• 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)

After you clone this repository and compile the program with the command above, you will generate a file called hsh that can be executed by entering ./hsh in your shell.

The output after the program is executed should look something like this:

$|

Where you will get a prompt in the shape of a dollar sign so you can start typing commands into your shell. Agood example of how it should execute is the command shown above were the user enters 'ls' and then gets a list of the directory contents.

Function Prototypes:

Brief description of functions contained in project:

_strcmpdir : compares strings to find dir. find_command : finds command to execute in path routes. charput : writes the character like putchar. place : similar to puts in C. _strlen : string length. str_concat : concatenate strings. lookforslash : identify if first char is a '/'. compareExit : checks if user typed exit. compareEnv : checks if user typed env. execute_proc : receives command and args from getline to be executed. identify_string : returns pointer with folder address. prompt : infinite loop with fork to keep prompt going. controlC: avoid program closing when pressing ctrl + c. main: initialize program.