HW2 - OS: Writing Your Own Shell

This repository contains the code and files for the second homework assignment in Operating Systems: Writing Your Own Shell.

Authors

Yosi Kariv - 205507460

Contact Information

For any questions or concerns, please reach out to the authors:

• Yosi Kariv: yosikariv@email.com

Project Overview

The project aims to create a custom shell that supports basic functionality such as executing commands, changing directories, and implementing various commands like pwd, cd, nano, cat, wc, cp, clear, grep, ls, executing pipes, and more.

This assignment helps gain experience with advanced programming techniques such as process creation, termination, and overriding an existing process (fork, wait, exec, and additional system calls).

Features

The custom shell supports the following features:

1. Print current working directory using pwd
2. Change the working directory using cd <path>
3. Create a file using cat > <filename> or nano <filename>
4. View the contents of a file using cat <filename>
5. Count words, lines, and characters in a file using wc [options/flags] <filename>
6. Copy files using cp <file1> <file2>
7. Support the pipe operator | between processes (only for two commands)
8. Clear the terminal using clear
9. Return lines with a specific word/string/pattern in a file using grep [options/flags] [Pattern] <filename>
10. List files and directories using ls [options/flags], with support for output redirection, e.g., ls -l > output_file
11. Print all files in the form of a tree structure using tree
12. Terminate the shell process using exit

Setup and Usage

1. Compile the code using a C compiler like GCC: gcc main.c -ll
2. Run the custom shell executable: ./a.out
3. Enter commands as you would in a regular shell, such as pwd, cd, nano, cat, wc, cp, clear, grep, ls, tree, and more.

Note: This custom shell has a limited set of features compared to a full-featured shell like Bash or Zsh. The focus of this project is on the implementation of basic shell functionality.

Helpful Resources

The following functions are some helpful functions for this project:

• fork, exec, execvp, wait, waitpid, dup, pipe, strncmp, strlen, malloc, free, getcwd, chdir, dup2, dup, open, close, readline, gets, fgets, getchar, 'dirent.h', opendir, readdir, closedir.