Module 1: Command-line and IDE Basics

Command Line Essentials

The command line is a text-based interface to interact with your computer. Different operating systems offer different terminal options:

• MacOS: Terminal (Bash, Zsh)
• Windows: Command Prompt, Git Bash, PowerShell

Basic Navigation Commands

• pwd - Shows current working directory (Print Working Directory)
• ls - Lists current contents of working directory
  • dir on Windows Command Prompt
  • ls -a displays all contents including hidden files
• cd - Change directory
  • cd .. moves one directory up
  • cd ~ moves directly to home directory
• clear - Clear the screen
  • cls on Windows
  • Command-K shortcut on MacOS

Working with Directories and Files

• mkdir - Create a directory
• touch - Creates a file
  • On Windows, use echo. or type nul > instead
• rm - Remove files
  • del on Windows
• rm -r - Remove directories
  • rmdir on Windows
• cp - Copy files
• mv - Move files or rename them

IntelliJ IDEA Basics

IntelliJ IDEA is a powerful Java IDE that provides advanced code editing features, debugging tools, and project organization capabilities.

Key Features

• Project Structure - Organize your code files and resources
• Code Completion - Intelligent suggestions as you type
• Refactoring Tools - Easily restructure your code
• Debugging - Step through code execution to find bugs
• Version Control Integration - Work with Git and other VCS

Essential Keyboard Shortcuts

• Ctrl+Space - Basic code completion
• Alt+Enter - Show intention actions and quick-fixes
• Ctrl+/ - Comment/uncomment line
• Shift+F10 - Run
• Shift+F9 - Debug
• Ctrl+N - Navigate to class
• Ctrl+Shift+N - Navigate to file

Note: On Mac, typically use Cmd instead of Ctrl.

Java Compilation Process

Understanding how Java code is compiled and executed is essential for efficient development:

The Process

1. Write code in .java files
2. Compile using javac to bytecode (.class files)
3. Run using the Java Virtual Machine (JVM) with java command

Example Compilation Workflow

// 1. Create a simple Java file named HelloWorld.java
public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

// 2. Compile from command line
javac HelloWorld.java

// 3. Run the compiled program
java HelloWorld

When using IntelliJ IDEA, this process is handled automatically when you click Run or press Shift+F10.

Command Line Practice

1. Open your terminal and navigate to your home directory.
2. Create a new directory called java_practice.
3. Navigate into this directory.
4. Create a file named Notes.txt.
5. List all files in the directory to confirm it was created.
6. Create a subdirectory called projects.
7. Move the Notes.txt file into the projects directory.

IntelliJ IDEA Practice

1. Download and install IntelliJ IDEA if you haven't already.
2. Create a new Java project.
3. Create a new Java class called HelloJava.
4. Write a simple program that prints "I'm learning Java!" to the console.
5. Run the program to verify it works.
6. Practice using keyboard shortcuts for code completion and navigation.