Your First Program

Hello, World

Create a folder and initialize a module — this is the Go equivalent of npm init or cargo init:

mkdir hello && cd hello
go mod init example.com/hello

This creates a go.mod file that names your module and tracks its dependencies. Now create main.go:

package main

import "fmt"

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

package main

import "fmt"

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

Every executable Go program needs a package main and a func main() — that’s the entry point. Run it directly with:

go run main.go

Building a binary

go run compiles and executes in one step, which is great for development. To ship something, compile a standalone binary:

go build -o hello .
./hello

The result is a statically linked binary with no runtime dependencies — you can copy it to another machine (same OS/arch) and it just runs. This is one of the reasons Go is popular for CLI tools and infrastructure software.

Anatomy of the program

package main declares this file belongs to the main package, the one Go treats as an entry point.
import "fmt" pulls in the standard library’s formatted I/O package.
func main() is called automatically when the binary starts. No arguments, no return value.

Cross-compiling is built into the toolchain via two environment variables, no extra tools needed:

GOOS=linux GOARCH=amd64 go build -o hello-linux .
GOOS=windows GOARCH=amd64 go build -o hello.exe .

This is exactly how most Go CLI tools ship prebuilt binaries for every platform from a single machine.