Turtle-Shell

Turtle-shell is a powerful and flexible command-line shell written in Python. It provides an interactive environment for executing system commands, managing files, and scripting tasks. It also includes built-in commands, command history, autocompletion, output redirection, and error handling for an efficient workflow.

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Features

• Built-in Commands:
  • exit [code]: Exits the shell with the provided exit code.
  • echo [text]: Prints the specified text to the console.
  • type [command]: Identifies whether a command is built-in or located in the system's PATH.
  • pwd: Displays the current working directory.
  • cd [directory]: Changes the current working directory, with support for ~ as the home directory.
• External Command Execution: Runs external programs available in the system's PATH.
• Autocompletion: Supports tab-based autocompletion using readline for faster command entry.
• Error Handling: Provides detailed error messages for incorrect commands or arguments.
• Output Redirection: Supports >, >>, 1>, and 2> for managing command output, including redirecting standard output and errors.
• Command History: Stores command history for easy recall and reuse using arrow keys.
• Platform Compatibility: Works seamlessly on Linux, macOS, and Windows.
• Alias Support (Future Implementation): Custom shortcuts for frequently used commands.

Installation

Prerequisites

• Python 3.6 or later installed on your system.
• Git installed for cloning the repository (optional).

Steps

# Clone the repository
git clone https://github.com/yourusername/Turtle-shell.git

# Navigate to the project directory
cd Turtle-shell

# Install dependencies 
pip install -r requirements.txt

Usage

Running the Shell

To start Turtle-shell, run the following command in your terminal:

python3 app/main.py

The shell will display a prompt ($), waiting for you to enter commands.

Built-in Commands

Command	Description
exit <code>	Exits the shell with the specified exit code.
echo <text>	Prints the given text to the console.
type <command>	Displays information about a given command (builtin or external).
pwd	Prints the current working directory.
cd <directory>	Changes the current directory to the specified location. Supports ~ for home.

Output Redirection

You can redirect command output using:

• > – Redirects standard output to a file (overwrite).
• >> – Redirects standard output to a file (append).
• 1> – Redirects standard output.
• 2> – Redirects standard error.

Example:

echo "Hello, World!" > output.txt  # Writes output to a file
echo "Appending text" >> output.txt  # Appends to a file
ls 1> output.log 2> error.log  # Separates standard output and error

Command History

Turtle-shell maintains a history of commands executed in the session. You can scroll through previous commands using the arrow keys and search command history using Ctrl + R.

External Commands

If a command is not built-in, the shell will attempt to execute it from the system's PATH.

Example:

$ ls
OUTPUT: file1.txt  file2.py  README.md

Some executable external commands include:

• bash
• cp
• mv
• rm
• git
• ls
• lazygit

Error Handling

• Invalid commands output:

  $ invalid_command
  OUTPUT: command not found
  

• Incorrect arguments for built-in commands display helpful error messages.
• Incorrect arguments for external commands display the relevant system error messages.
• Unterminated Quotes Handling: Detects missing quotes and notifies users.

Code Overview

Main Components:

Built-in Commands:

• exit: Exits the shell with an optional exit code.
• echo: Prints user input.
• type: Identifies commands.
• pwd: Prints the current directory.
• cd: Changes the working directory, supporting ~ for the home directory.

External Commands:

• The shell checks if a command exists in the system's PATH and executes it.

Helper Functions:

• executable_file(command): Checks if a command is executable in the system's PATH.
• Platform-Specific Behavior: The cd command resolves the home directory differently on Linux (HOME) and Windows (USERPROFILE).
• Command Autocompletion: Uses readline for efficient tab-based command completion.

Contribution

Contributions are welcome! If you want to enhance Turtle-shell:

1. Fork the repository.
2. Create a new branch for your feature or bug fix.
3. Commit your changes and push the branch.
4. Submit a pull request for review.

Turtle-shell Release

Notice!: The v.0.1.11 works if you run it with a terminal app like Kitty, PowerShell, or Alacritty.

License

This project is licensed under the MIT License. See the LICENSE file for more details.

Contact

For any questions, suggestions, or issues, feel free to reach out via GitHub issues.

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