Getting Started with Go: Your First Steps in Writing, Running, and Building Programs

Welcome to the world of Go programming language, also known as Golang! If you are new to Go, this guide is perfect for you. We’ll walk you through creating a simple "Hello, World!" program, explain each line of code, and show you how to run and build your first Go application.

By the end of this tutorial, you’ll have a solid understanding of Go’s basic syntax, how to write code, and how to build an executable file. Let’s get started!

What is Go?

Go is an open-source programming language developed by Google. It is designed to be simple, efficient, and easy to learn. Go combines the performance of low-level languages like C with the simplicity of high-level languages like Python. It’s particularly well-suited for building web servers, cloud services, and command-line tools.

Prerequisites

Before we start coding, make sure you have Go installed on your machine. If you haven’t installed Go yet, check out our guide on installing and setting up Go.

Checking Your Go Installation

To confirm that Go is installed correctly, open your terminal (or Command Prompt on Windows) and run:

go version

You should see output like:

go version go1.x.x linux/amd64

If you see this, you’re good to go!

Writing Your First Go Program

Let’s dive into writing a simple "Hello, World!" program in Go.

Step 1: Create a New Go File

1. Open your terminal or code editor (VS Code, for example).

2. Create a new directory for your project:

    mkdir hello-go
    cd hello-go
   

3. Create a new file named main.go:

    touch main.go
   

Step 2: Write the Code

Open main.go in your editor and type the following code:

package main

import "fmt"

func main() {
    fmt.Println("Hello, World!")
}

Let’s break this down line by line and understand each part.

Code Explanation

Line 1: package main

package main

• In Go, every file begins with a package declaration.

• A package is a way to group related code together. The main package is special in Go — it tells the Go compiler that this file is the entry point of the program.

• When you run a Go program, the main package and its main function are executed first.

Line 3: import "fmt"

import "fmt"

• The import keyword is used to include packages in your program.

• Here, we are importing the fmt package, which provides functions for formatted I/O (input and output).

• fmt stands for "format," and it includes functions like Println, Printf, and Scanln for printing to the console.

Line 5: func main()

func main() {

• This line defines a function named main.

• In Go, every executable program must have a main function. It is the entry point of the program and is automatically called when the program starts.

• The func keyword is used to declare a function.

Line 6: fmt.Println("Hello, World!")

fmt.Println("Hello, World!")

• This line prints the text "Hello, World!" to the console.

• fmt.Println is a function from the fmt package. The Println function stands for "print line," and it prints the text followed by a newline character.

• The string "Hello, World!" is enclosed in double quotes ("), indicating it is a string literal.

Line 7: Closing the Function

}

• This curly brace (}) indicates the end of the main function.

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Running Your Go Program

Now that we’ve written the code, let’s run it and see the output.

Step 1: Run the Program

In your terminal, navigate to the directory containing main.go and type:

go run main.go

Output

Hello, World!

Explanation:

• The go run command compiles and runs the program in one step. It’s perfect for quickly testing your code.

• You should see the text "Hello, World!" printed on the screen.

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Building Your Go Program

While go run is convenient, it’s mainly used for testing and development. When you’re ready to share your program or deploy it, you’ll want to build it into an executable file.

Step 1: Build the Executable

To build the program, use the go build command:

go build main.go

Step 2: Run the Executable

After running go build, you’ll find an executable file named main (on Linux or macOS) or main.exe (on Windows) in your directory. Run the executable using:

• On Linux/macOS:

    ./main
  

• On Windows:

    main.exe
  

Output

Hello, World!

Explanation:

• The go build command compiles the source code into a standalone executable file.

• This file can be distributed and run on any machine without requiring Go to be installed.

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Understanding Go’s Workflow

To summarize the Go development process:

1. Write the code in a .go file.

2. Run the code using go run for quick testing.

3. Build the code using go build to create an executable file.

4. Execute the built program directly to see the output.

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Additional Tips for Beginners

1. Go File Naming Conventions

• Go files usually have a .go extension.

• The main file is often named main.go, but you can use any name that follows Go’s naming conventions (lowercase, no spaces, use underscores or camelCase).

2. Formatting Your Code

Go has a built-in tool called gofmt that automatically formats your code according to standard Go conventions. To format your code, simply run:

gofmt -w main.go

This helps maintain consistency and readability in your code.

3. Checking for Errors

Go provides a command to quickly check your code for syntax errors:

go vet main.go

If there are any issues, go vet will point them out, making it easier to debug your program.

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Conclusion

You’ve just written, run, and built your first Go program! 🎉 In this guide, we covered:

• The basic structure of a Go program.

• Line-by-line explanation of the "Hello, World!" code.

• How to run and build a Go program.

• Helpful tips for getting started with Go.

Go is a powerful language, and this is just the beginning. As you continue learning, you’ll discover Go’s unique features, such as its excellent concurrency model, robust standard library, and strong performance.

Stay tuned for more tutorials where we’ll explore Go’s data types, control structures, functions, and advanced features. Happy coding with Go!