Simple Unix Shell

Overview

This project is a simple Unix shell written in C. It provides an interactive command-line environment that supports executing commands, handling pipelines, managing background jobs, and performing basic input/output redirection.

Features

✅ Command Execution

• Executes Unix commands using execvp.
• Supports command-line arguments.

✅ Tokenization and Parsing

• Splits user input into tokens while respecting quotes and escape sequences.
• Supports variable expansion (e.g., $HOME).
• Expands wildcard patterns (* and ?) using glob.

✅ Pipelining

• Supports chaining commands using the pipe (|) operator.
• Redirects output of one command to the input of another.

✅ I/O Redirection

• Input redirection (<): Read from a file instead of standard input.
• Output redirection (>): Write output to a file (overwrite mode).
• Append redirection (>>): Write output to a file (append mode).
• Stderr redirection (2>&1): Redirects stderr to stdout.

✅ Background Job Execution

• Commands ending with & run in the background.
• Supports listing background jobs with jobs.

✅ Built-in Commands

• exit - Exits the shell.
• cd - Changes the working directory.
• clear - Clears the screen.
• jobs - Displays running background jobs.
• export - Sets environment variables.

✅ Signal Handling

• Handles SIGINT (Ctrl+C) to prevent shell termination.
• Gracefully handles child process termination.

Installation & Usage

📥 Installation

1. Clone this repository:

   git clone https://github.com/jordyorel/orus_shell.git
   cd orus_shell

2. Compile the shell:

   gcc -o orus main.c -lreadline

3. Run the shell:

   ./orus

📌 Usage

Once inside the shell, you can:

• Run commands like ls, grep, cat, etc.
• Use pipes: ls | grep .c
• Redirect output: ls > output.txt
• Run background processes: sleep 10 &
• List jobs: jobs
• Change directories: cd /path/to/directory
• Exit: exit

Limitations & Future Improvements

❌ Current Limitations

• No support for command substitution ($(command)).
• No job control commands (fg, bg, Ctrl+Z).
• No scripting capabilities (loops, conditionals, functions).
• Limited error handling for syntax errors.

🚀 Future Enhancements

• Implement fg and bg commands for job control.
• Improve error messages and debugging support.
• Add support for command substitution.
• Implement signal handling for stopping/resuming jobs (Ctrl+Z).

Contributing

Feel free to fork the project and submit pull requests! For major changes, please open an issue first to discuss what you’d like to change.

License

This project is licensed under the MIT License.