Jamatia's Mini OS Shell

Welcome to Jamatia's Mini OS Shell—a custom, interactive shell environment designed to simulate basic command-line operations for both Windows and Mac/Linux systems. This shell offers built-in commands, environment-specific functions, and session time-tracking, making it a unique utility for practicing and experimenting with common shell commands.

Objective

The main objective of this project is to create a lightweight and interactive shell environment that simulates basic command-line functionality for both Windows and Mac/Linux operating systems. This shell will help users:

• Learn and practice essential shell commands used in different OS environments.
• Understand the behavior and syntax of various system-level commands.
• Experiment with file management, network utilities, and process control using a command-line interface.
• Track session time and gain insights into shell usage patterns.
• Provide an accessible platform for users to interact with and explore different operating system environments via a single shell interface.

Technologies Used

• C Programming Language: The shell is implemented in C, providing low-level control over system processes.
• Visual Studio Code: Used as the primary Integrated Development Environment (IDE) for coding, debugging, and testing the Mini OS Shell.

The Art of C in Shell Development

This project highlights several important aspects of C programming, demonstrating both basic and advanced techniques:

1. Standard Input/Output (I/O)

• Usage of printf and scanf: These functions are used to interact with the user, display information, and read user inputs.
• Example:

  printf("Select environment (Windows/Mac/Linux): ");
  scanf("%s", environment);

2. String Manipulation

• Handling strings: The project involves manipulating strings using C string functions like strcpy, strlen, and strcmp.
• Example:

  if (strcmp(command, "exit") == 0) {
      printf("Exiting the shell...\n");
      break;
  }

3. Memory Management

• Dynamic Memory Allocation: malloc and free are used to allocate and deallocate memory dynamically for various data structures (like user inputs).
• Example:

  char *input = (char *)malloc(100 * sizeof(char));
  if (input == NULL) {
      printf("Memory allocation failed\n");
      exit(1);
  }
  free(input);

4. Process Control

• System Calls and fork(): Using fork() to create new processes and execvp() to execute commands in a child process.
• Example:

  pid_t pid = fork();
  if (pid == 0) {
      execvp(command, args);  // Execute command in child process
  } else {
      wait(NULL);  // Parent waits for child process to finish
  }

5. File I/O

• File Operations: Using fopen(), fclose(), fread(), and fwrite() to interact with files, simulating file navigation and management commands.
• Example:

  FILE *file = fopen("example.txt", "r");
  if (file != NULL) {
      fread(buffer, sizeof(char), 100, file);
      fclose(file);
  }

6. Control Structures

• Conditionals and Loops: Mastery of if, else, for, and while loops to control program flow based on user inputs and command execution.
• Example:

  while (1) {
      printf("MiniShell> ");
      fgets(command, 100, stdin);
      if (strcmp(command, "exit") == 0) break;
  }

7. Error Handling

• Error Checking: Proper error handling is implemented using perror() and checking return values of system calls and library functions.
• Example:

  if (system(command) == -1) {
      perror("Command execution failed");
  }

8. Session Time Tracking

• Time Functions: Using the time.h library to track session time and display elapsed time after each command.
• Example:

  time_t start_time, end_time;
  time(&start_time);
  // Execute command...
  time(&end_time);
  printf("Time spent in shell: %.2f seconds\n", difftime(end_time, start_time));

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Features

• Dual Environment Simulation: Choose between Windows and Mac/Linux environments to simulate commands specific to each OS.
• Command Execution: Support for basic and system-level commands, including file navigation, directory management, and network utilities.
• Elapsed Time Tracking: Track and display time spent in the shell after each command, with a session summary upon exit.
• Help System: A built-in help command displaying a table of supported commands with examples for easy reference.

Project Structure

The Mini OS Shell project is implemented in a single C file with easy-to-follow code that includes comments for better readability.

Table of Contents

• Installation
• Usage
  • Supported Commands
  • Environment-Specific Commands
  • Command Examples
• Contributing
• License

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Installation

1. Clone the repository:

   git clone https://github.com/your-username/mini-os-shell.git
   cd mini-os-shell

2. Compile the shell program:

   gcc mini_os_shell.c -o mini_os_shell

3. Run the shell program:

   ./mini_os_shell

Usage

When you run the shell, it will prompt you to select an environment:

• Windows: Simulates commands typically available on Windows.
• Mac/Linux: Simulates commands specific to Unix-like systems.

Once an environment is selected, the shell will display a welcome message, and you can start entering commands.

Supported Commands

Command	Description	Example
help	Display help information with available commands	help
exit / quit	Exit the shell	exit
pwd	Print the current directory	pwd
cd <dir>	Change directory	cd Documents
ls / dir	List files and directories	ls or dir
clear	Clear the terminal screen	clear
tree	Display directory structure	tree
ipconfig / ifconfig	Display network configuration info	ipconfig or ifconfig
ping <host>	Check network connectivity	ping google.com
nslookup <host>	DNS lookup for hostname	nslookup example.com
traceroute / tracert	Trace packet route to host	traceroute example.com
netstat	Display network connections and stats	netstat
curl <url>	Fetch data from specified URL	curl http://example.com
hostname	Display the system hostname	hostname
mkdir <dir>	Create a new directory	mkdir NewFolder
rmdir <dir>	Remove an empty directory	rmdir NewFolder
rm <file>	Remove a file	rm file.txt
ps	List running processes	ps
kill <pid>	Terminate a process by process ID	kill 1234
top / tasklist	Display active processes	top or tasklist
df / diskpart	Display disk usage and partition info	df or diskpart
history	Display command history	history

Environment-Specific Commands

• Windows Only:

  • dir: Lists directory contents
  • tasklist: Shows all running processes
  • diskpart: Disk partition utility

• Mac/Linux Only:

  • ls: Lists directory contents
  • ifconfig: Displays network configuration
  • top: Displays active processes
  • df: Shows disk usage

Command Examples

1. Navigating Directories:

   MiniShell> cd Documents

2. Network Utility:

   MiniShell> ping google.com

3. Clearing the Screen:

   MiniShell> clear

4. Exit Shell:

   MiniShell> exit

5

. Help:

MiniShell> help

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Contributing

Contributions are welcome! Please fork the repository and submit a pull request for any changes or improvements. You can also open an issue if you encounter any bugs or have feature requests.

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License

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

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