README.md

🐚 Custom UNIX Shell in C

This project is a fully functional UNIX-like shell implemented in C. It replicates core shell features such as command execution, redirection, piping, and more. The shell provides a command-line interface to interact with the operating system, similar to bash or sh.

---

🚀 Features

1. Command Prompt

   • Displays the current working directory appended with a custom prompt (sh> ) and reads user input interactively.

     E.g., /mnt/d/C's/UNIX_Shell sh

2. Command Execution

   • Executes standard system commands using fork() and exec() system calls.
   • To be specific all the executable programs listed in the root's bin directory can be executed in this custom shell.
   • Example: pwd will display the current working directory, ls will list files and folders, mkdir for creating directory etc.

3. Input and Output Redirection

   • Supports < for input redirection.
   • Supports > for overwrite output redirection.
   • Supports >> for append output redirection.
   • Example:

     cat < input.txt > output.txt

4. Command Piping

   • Supports piping (|) between any number of commands.
   • Example:

     cat file.txt | grep "data" | sort | uniq

5. Multiple Commands

   • Allows multiple commands on the same line separated by a semicolon (;).
   • Example:

     pwd; ls; whoami

6. Conditional Command Execution

   • Supports && to run the next command only if the previous one succeeds.
   • Example:

     mkdir test && cd test

7. Command History

   • Maintains a history of executed commands during the shell session. By typing history onto the shell, all the commands executed while running the program will be listed.

8. Signal Handling

   • Handles SIGINT (Ctrl+C) to terminate only the foreground process, not the shell itself.

---

Commands like exit, cd & history were handled in a separate function as thses are not executables from the bin directory so the "execvp()" function won't work for these.

🛠️ Build Instructions

Prerequisites

• GCC compiler
• POSIX-compliant system (Linux, macOS, WSL, etc.)

Compile

Use the following command to compile the shell:

gcc -o myshell main.c

Contributing

Contributions are welcome! To contribute:

1. Fork the repository.
2. Create a new branch (git checkout -b feature-branch).
3. Make your changes and commit them (git commit -m "Add feature").
4. Push to your fork (git push origin feature-branch).
5. Open a pull request.

Please ensure your code follows the project's coding style and includes appropriate comments.