/test-simple-shell

Primary LanguageC

Simple Shell Project

A simple Unix command line interpreter shell

Table of contents

  • What is the shell?
  • About this project
  • Essential Functionalities of the Simple Shell
  • File description

What is the shell?

The shell is a program that takes commands from the keyboard via the terminal, and gives them to the operating system to perform.
To better understand how the shell actually works, you can read our [Article].

About this project

This project is a simple version of the linux shell made for [Alx School] taking part of the "Low-level programming & Algorithm - Linux and Unix system programming" projects.
It is created using the C programming Language and it can do many functionalities that a real shell does.

Essential Functionalities of the Simple Shell:

Displays a prompt "#cisfun$ " and waits for user input.
Runs all commands of type "executable program" (ls and /bin/ls).
Runs the following build_in commands: exit, env, setenv and unsetenv.
Handles commands with arguments.
Handles the PATH global variable.
Handles The EOF (End Of File) condition.
Handles the Ctrl + C signal -> It doesn't exit the shell

Files description

  • AUTHORS -> List of contributors to this repository
  • man_1_simple_shell -> Manual page for the simple_shell
  • shell.h -> Header file
  • shell.c -> main function
    • sig_handler -> handles the Ctrl + C signal
    • _EOF -> handles the End Of File condition
  • string.c
    • _putchar -> prints a character
    • _puts -> prints a string
    • _strlen -> gives the length of a string
    • _strdup -> copies a string in a newly allocated memory
    • concat_all -> concatenates 3 strings in a newly allocated memory
  • line_exec.c
    • splitstring -> splits a string into an array of words
    • execute -> executes a command using execve
    • realloc -> reallocates a memory block
    • freearv -> frees a 2 dimensional array
  • linkpath.c
    • _getenv -> returns the value of a global variable
    • add_node_end -> adds a node in a singly linked list
    • linkpath -> creates a singly linked list for PATH directories
    • _which -> finds the pathname of a command
    • free_list -> frees the linked list of PATH value
  • checkbuild.c
    • checkbuild -> checks if a command is a build-in command
  • buildin.c
    • exitt -> handles the exit buildin command
    • _atoi -> converts a string into an integer
    • env -> prints the current environment
    • _setenv -> Initialize a new global variable, or modify an existing one
    • _unsetenv -> remove a global variable