In this tutorial, you'll get a brief introduction to Go programming. Along the way, you will:
go
command to run your code.Just use the Download and install steps.
Write some codeGet started with Hello, World.
On Linux or Mac:
cd
On Windows:
cd %HOMEPATH%
For example, use the following commands:
mkdir hello cd hello
When your code imports packages contained in other modules, you manage those dependencies through your code's own module. That module is defined by a go.mod file that tracks the modules that provide those packages. That go.mod file stays with your code, including in your source code repository.
To enable dependency tracking for your code by creating a go.mod file, run the go mod init
command, giving it the name of the module your code will be in. The name is the module's module path.
In actual development, the module path will typically be the repository location where your source code will be kept. For example, the module path might be github.com/mymodule
. If you plan to publish your module for others to use, the module path must be a location from which Go tools can download your module. For more about naming a module with a module path, see Managing dependencies.
For the purposes of this tutorial, just use example/hello
.
$ go mod init example/hello go: creating new go.mod: module example/hello
In your text editor, create a file hello.go in which to write your code.
Paste the following code into your hello.go file and save the file.
package main import "fmt" func main() { fmt.Println("Hello, World!") }
This is your Go code. In this code, you:
main
package (a package is a way to group functions, and it's made up of all the files in the same directory).fmt
package, which contains functions for formatting text, including printing to the console. This package is one of the standard library packages you got when you installed Go.main
function to print a message to the console. A main
function executes by default when you run the main
package.Run your code to see the greeting.
$ go run . Hello, World!
The go run
command is one of many go
commands you'll use to get things done with Go. Use the following command to get a list of the others:
$ go help
When you need your code to do something that might have been implemented by someone else, you can look for a package that has functions you can use in your code.
rsc.io/quote
package (it should be listed with the "Other major versions" of rsc.io/quote/v4
).Go
function.quote
is included in the rsc.io/quote
module.You can use the pkg.go.dev site to find published modules whose packages have functions you can use in your own code. Packages are published in modules -- like rsc.io/quote
-- where others can use them. Modules are improved with new versions over time, and you can upgrade your code to use the improved versions.
rsc.io/quote
package and add a call to its Go
function.
After adding the highlighted lines, your code should include the following:
package main import "fmt" import "rsc.io/quote" func main() { fmt.Println(quote.Go()) }
Go will add the quote
module as a requirement, as well as a go.sum file for use in authenticating the module. For more, see Authenticating modules in the Go Modules Reference.
$ go mod tidy go: finding module for package rsc.io/quote go: found rsc.io/quote in rsc.io/quote v1.5.2
$ go run . Don't communicate by sharing memory, share memory by communicating.
Notice that your code calls the Go
function, printing a clever message about communication.
When you ran go mod tidy
, it located and downloaded the rsc.io/quote
module that contains the package you imported. By default, it downloaded the latest version -- v1.5.2.
With this quick introduction, you got Go installed and learned some of the basics. To write some more code with another tutorial, take a look at Create a Go module.
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