/linux-shell-c

This repository contains the source code and documentation for MyShell, a simple Linux shell developed using C programming language as part Operating Systems course.

Primary LanguageCMIT LicenseMIT

MyShell: Custom Command Line Interpreter

This repository contains the source code and documentation for MyShell, a simple Linux shell developed using C programming language.

Table of Contents

Introduction

MyShell is a simple command line interpreter that mimics the functionality of a standard Linux shell. It supports several internal commands and introduces a unique custom command for additional functionality.

Features

MyShell supports the following internal commands:

  1. mycd <directory>: Change the current directory to <directory>. Reports the current directory if <directory> is not provided. Reports an error if the directory does not exist.
  2. myclr: Clears the screen.
  3. mydir <directory>: Lists the contents of <directory>.
  4. myenviron: Lists all environment strings.
  5. myecho <comment>: Displays <comment> followed by a new line.
  6. myhelp: Displays the user manual using the standard more filter.
  7. mypause: Pauses the shell until 'Enter' is pressed.
  8. myquit: Quits the shell.
  9. myone: A custom command providing unique functionality not found in standard Linux commands.

Additionally, the command line prompt contains the pathname of the current directory.

Installation

To install MyShell,navigate to your desired directory in Linux and follow these steps:

  1. Clone the repository: 
    git clone https://github.com/Lite30/linux-shell-c.git
cd linux-shell-c
  2. Compile the source code using the provided Makefile by entering: 
    make

Usage

  1. To use the shell simply enter 
    ./myshell

in the terminal and a welcome screen should appear.

Commands

Internal Commands

mycd <directory>

  • Changes the current directory to .
  • If is not provided, it reports the current directory.
  • Reports an error if the directory does not exist. -Changes the PWD environment variable accordingly.

myclr

  • Clears the terminal screen.

mydir <directory>

  • Lists the contents of .

myenviron

  • Lists all the environment variables.

myecho <comment>

  • Displays followed by a new line. Reduces multiple spaces/tabs to a single space.

myhelp

  • Displays the user manual using the standard more filter.

mypause

  • Pauses the shell until 'Enter' is pressed.

myquit

  • Exits the shell.

myone

  • A unique command that provides functionality not offered by standard Linux commands. Detailed description and usage instructions for myone are provided below.

Implementation-details

Implementation Details

mycd <directory>

  • Uses the chdir system call to change the directory..
  • Updates the PWD environment variable..
  • Reports an error if the directory does not exist. -Changes the PWD environment variable accordingly.

myclr

  • Uses ANSI escape codes to clear the screen..

mydir

  • Uses opendir, readdir, and closedir functions to list directory contents.

myenviron

  • Iterates through the environment variables using the environ pointer. myecho

  • Prints the arguments to the standard output, ensuring multiple spaces/tabs are reduced to a single space..

myhelp

  • Uses the more filter to display the user manual, typically found in a help text file..

mypause

  • Pauses the shell until 'Enter' is pressed.

myquit

  • Exits the shell using the exit system call..

myone

  • A unique command that provides functionality not offered by standard Linux commands..

Implementation:

Reads from the /proc/uptime file and displays the system uptime in a human-readable format.

Makefile

A Makefile is provided to compile the source code. Use the following command to compile:

make

Contributing

  • Fork the repository.
  • Create a new branch (git checkout -b feature-branch).
  • Make your changes and commit them (git commit -m 'Add new feature').
  • Push to the branch (git push origin feature-branch).
  • Open a Pull Request.

Release-Notes

version 1.0- 28 May 2024

  • Initial Release

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contacts

Co-authors