🖥️ JCLI - Java Command Line Interface

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🚀 A Powerful Unix-like CLI Built with Modern Java

JCLI combines the familiarity of traditional shell commands with robust Java architecture, comprehensive testing, and cross-platform compatibility.

🚀 Project Overview

JCLI is a comprehensive CLI shell implementation that recreates essential Unix/Linux commands in pure Java. It features a modular architecture, extensive testing suite, and advanced capabilities like command piping, output redirection, aliases, and persistent configuration.

✨ Key Highlights

🔥 20+ Built-in Commands Complete implementation of essential CLI tools 🔗 Command Pipeline Support Unix-style piping with | operator 📤 Output Redirection Redirect command output to files with > ⚙️ Persistent Configuration Aliases and settings stored in ~/.clirc

📚 Command History Full history tracking with search capabilities 🛡️ Path Security Built-in protection against directory traversal attacks 🌐 Cross-Platform Runs on Windows, Linux, and macOS ⚡ Native Compilation GraalVM support for fast, native executables

📋 Features

Core Commands

Command	Syntax	Description
help	help [command]	Show all commands or help for specific command
echo	echo [args]	Print arguments to console
pwd	pwd	Print current working directory
cd	cd [dir]	Change directory (default: home)
ls	ls [-r -l -a]	List directory contents with options
cp	cp [-r -i] [src] [dest]	Copy files/directories
mv	mv [-i] [src] [dest]	Move/rename files
mkdir	mkdir [dir]	Create directory
rmdir	rmdir [dir]	Remove empty directory
rm	rm [file]	Remove file
rm -r	rm -r [dir]	Remove directory recursively
touch	touch [file]	Create empty file or update timestamp
cat	cat [file]	Display file contents
grep	grep [-i -n] [pattern] [file]	Search text patterns
wc	wc [file]	Count lines, words, characters
head	head [-n N] [file]	Display first N lines (default: 10)
tail	tail [-n N] [file]	Display last N lines (default: 10)
sort	sort [-r] [file]	Sort lines alphabetically
find	find [-name pattern]	Find files matching pattern
history	history [-c -n N]	Show command history
clear	clear	Clear terminal screen
date	date	Display current date and time
alias	alias [name=command]	Create command aliases
exit	exit	Exit the CLI

Advanced Features

🔗 Command Piping

Chain commands together with Unix-style piping:

cat file.txt | grep "pattern" | sort | head -5
find . -name "*.txt" | head -10
ls -l | grep "2024"

📤 Output Redirection

Redirect command output to files:

echo "Hello World" > output.txt
ls -l > directory_listing.txt
date > timestamp.txt

🔗 Command Aliases

Create shortcuts for frequently used commands:

alias ll='ls -l'
alias la='ls -a'
alias grep-java='grep -i java'

⚙️ Configuration Management

• Config file: ~/.clirc stores aliases and prompt settings
• Persistent aliases: Automatically loaded on startup
• Custom prompt: Configurable command prompt format

📚 Command History

• Persistent storage: History saved to ~/.cli_history
• Search capabilities: history -n 20 shows last 20 commands
• History clearing: history -c clears all history

🛠️ Technical Details

Architecture

• Language: Java 21 with modern features (records, pattern matching, text blocks)
• Build System: Maven 3.9+ with comprehensive dependency management
• Logging: SLF4J with Logback for structured logging
• Testing: JUnit 5 with extensive unit and integration tests
• Code Coverage: JaCoCo integration for test coverage analysis

Security Features

• Path Validation: Automatic prevention of directory traversal attacks
• Safe File Operations: All file operations validate paths against working directory
• Input Sanitization: Command arguments are properly validated and escaped

Performance & Compatibility

• Cross-Platform: Native support for Windows, Linux, and macOS
• Memory Efficient: Optimized for low memory footprint
• Fast Startup: Sub-second startup time
• Native Compilation: GraalVM support for native executables

📦 Prerequisites

Required Software

Tool	Version	Verification Command
JDK 21	OpenJDK 21+	java -version
Maven	3.9+	mvn -version
Git	Latest	git --version

Development Environment

Recommended IDE: VS Code

Install VS Code from code.visualstudio.com with these extensions:

• Java Extension Pack - Complete Java development support
• Maven for Java - Maven project management
• GitLens - Enhanced Git capabilities (optional)

Optional: GraalVM (for native compilation)

• GraalVM 21 - For creating native executables
• Enables ultra-fast startup and reduced memory usage

🚀 Installation & Setup

1. Install Development Tools

JDK 21 Installation

# Linux (Ubuntu/Debian)
sudo apt install openjdk-21-jdk

# macOS (Homebrew)
brew install openjdk@21

# Windows
# Download from https://adoptium.net/

Maven Installation

# Linux
sudo apt install maven

# macOS
brew install maven

# Windows
# Download from https://maven.apache.org/download.cgi

Git Installation

# Linux
sudo apt install git

# macOS
brew install git

# Windows
# Download from https://git-scm.com/download/win

2. Clone and Build

# Clone the repository
git clone https://github.com/MuhammadAliAsgher/JCLI.git
cd JCLI

# Build the project
mvn clean compile

# Run tests
mvn test

# Create executable JAR
mvn package

# Run the application
java -jar target/JCLI-1.0-SNAPSHOT.jar

3. Development Setup

VS Code Configuration

1. Open project in VS Code: code .
2. Install recommended extensions when prompted
3. VS Code will automatically configure Java classpath and build settings

Maven Integration

• Compile: mvn compile
• Test: mvn test
• Package: mvn package
• Clean: mvn clean

🎯 Usage Examples

Basic File Operations

# Navigate and explore
pwd
ls -la
cd Documents
mkdir projects
cd projects

# Create and edit files
touch README.md
echo "# My Project" > README.md
cat README.md

Text Processing Pipelines

# Find and filter files
find . -name "*.java" | head -10
ls -l | grep "txt" | sort

# Process file contents
cat logfile.txt | grep "ERROR" | wc
head -20 data.csv | tail -5

Command Aliases

# Create useful shortcuts
alias ll='ls -l'
alias la='ls -a'
alias projects='cd ~/Documents/projects'

# Use aliases
ll
la
projects

History and Navigation

# View command history
history
history -n 10

# Clear screen and history
clear
history -c

🧪 Testing

The project includes comprehensive testing coverage:

# Run all tests
mvn test

# Run specific test class
mvn test -Dtest=ShellIntegrationTest

# Generate coverage report
mvn jacoco:report

# View coverage report
open target/site/jacoco/index.html

Test Coverage

• Unit Tests: Individual command testing with mocks
• Integration Tests: End-to-end workflow validation
• Security Tests: Path traversal and input validation
• Performance Tests: Memory and execution time validation

🔧 Advanced Configuration

Custom Aliases

Edit ~/.clirc to add persistent aliases:

alias ll='ls -l'
alias la='ls -a'
alias grep-java='grep -i java'
prompt=%s $

Environment Variables

• JCLI_HOME: Override default configuration directory
• JCLI_HISTORY_SIZE: Set maximum history entries (default: 1000)

Native Compilation (GraalVM)

# Install GraalVM native-image
gu install native-image

# Create native executable
native-image -jar target/JCLI-1.0-SNAPSHOT.jar jcli

# Run native executable
./jcli

🤝 Contributing

We welcome contributions! Here's how to get started:

1. Fork the repository on GitHub
2. Create a feature branch: git checkout -b feature/amazing-feature
3. Make your changes with appropriate tests
4. Commit changes: git commit -m 'Add amazing feature'
5. Push to branch: git push origin feature/amazing-feature
6. Open a Pull Request with detailed description

Development Guidelines

• Follow Java coding standards and conventions
• Add tests for new features and bug fixes
• Update documentation for user-facing changes
• Ensure all tests pass before submitting PR

📝 License

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

🙏 Acknowledgments

• Inspired by Unix/Linux command-line tools
• Built with modern Java 21 features
• Comprehensive testing with JUnit 5
• Maven build system and dependency management

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