Hikio Shell

Hikio is a lightweight, Unix-like shell written in C, designed to provide essential shell functionality made only for learning purpose and to explore how shell works under the hood.

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✨ Features

• ✅ Built-in Commands
  • cd, pwd, clear, exit, help
• ✅ Piping
  • Chaining commands with |
• ✅ Redirection
  • Input redirection: <
  • Output redirection (overwrite): >
  • Output redirection (append): >>
• ✅ Tilde Expansion
  • ~ expands to home directory
• ✅ Environment Variable Expansion
  • e.g., $HOME, $USER, $PATH
• ✅ Command History
  • Arrow keys to navigate previously entered commands
• ✅ Autocompletion
  • Press Tab to auto-complete files/commands from the current directory

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📚 Built-in Commands

Command	Description
cd	Change current directory
pwd	Print current working directory
clear	Clear the terminal screen
exit	Exit the shell
help	Display help for built-ins

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🔍 Examples

$ cd ~/Projects
# Navigate to ~/Projects using tilde expansion

$ echo $USER
# Expands environment variable

$ ls | grep ".c"
# Pipe output from ls to grep

$ sort < unsorted.txt > sorted.txt
# Redirect input and output

$ sleep 10 &
# Run sleep in the background

$ ./hikio
# Start the custom shell

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🛠 Installation

📦 Requirements

• GCC
• GNU Make
• readline library
• Optional (for better IDE support): bear

1. Clone the repository:

   git clone https://github.com/saber-88/hikio.git
   cd hikio

2. Run the setup script:

   ./setup.sh

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🧪 Development Mode

To just build for development (without installing system-wide):

make clean
bear -- make
./hikio

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🧠 Under the Hood

Hikio uses:

• fork(), execvp(), waitpid() for process creation
• readline for history & input line editing
• dup2() for redirection
• pipe() to implement |
• opendir()/readdir() for autocompletion
• getenv() for variable/tilde expansion

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📌 Note

• Icons and colorized output for files can be added in future enhancements.
• No external dependencies apart from GNU Readline.

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📜 License

GPL

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🤝 Contributing

Pull requests and issues are welcome. This shell is built for educational purposes and open for enhancements.

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👤 Author

Developed by Karmveer

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