• From 0 to Hello World
  • Next steps

From 0 to Hello World

Let's say that you have brand new Macbook straight from the factory, here's what you need

  • XCode Commandline Tools
  • brew
  • go
  • $GOPATH

And here's how you get it:

XCode

Open up Terminal.app and copy and paste the following:

xcode-select --install

That will open up a window that asks you "are you sure blah blah blah". Just go with the affirmatives.

Once it's finished you should be able to use git:

git --version

If that didn't work you may need to logout and log back in or restart your computer. If it still doesn't work just try the xcode-select install a second time.

brew

Next you need to get brew (aka Homebrew), which is basically the open-source app store for OS X (similar to apt-get on Linux).

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

That should only take a minute. You can (and should) test that it installed correctly:

brew doctor

Go

And finally you can install go.

brew install go

$GOPATH

Before you can use go you need to create and set your $GOPATH.

I like to put mine under my Code folder:

mkdir -p ~/Code/go

Then open ~/.bashrc in your favorite text editor, or vim, and set $GOPATH.

vim ~/.bashrc

export GOPATH="${HOME}/go"
export PATH="${GOPATH}/bin:${PATH}"

Finally, you must refresh your current settings:

source ~/.bashrc

Great! Now you're ready to go!

(see what I did there?)

fish

If you use fish (and if you don't know, then you don't), you set yours like so:

vim ~/.config/fish/fish.config

set -gx GOPATH "$HOME/Code/go"
set -gx PATH "$GOPATH/bin" $PATH

Then refresh your current config

. ~/.config/fish/config.fish

Hello World!

Now we can make a little project to print "Hello, World!" to the console:

vim /tmp/hello.go

package main

import "fmt"

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

Then you can run it just like you would a script:

go run /tmp/hello.go

Or you can compile it and run it as a binary

go build -o /tmp/hello /tmp/hello.go

/tmp/hello

Next steps

  • goimport
  • gofmt
  • godoc
  • igo

You'll probably want to learn a little about setting up your development environment.

I have some info on getting go setup with vim in another article:

https://coolaj86.com/articles/today-i-became-a-golang-dev-with-vim-and-caddy/

It's a good idea to think of a small problem that you want to solve and then, instead of solving it the way you normally would, solve it in Go.

For example, I wanted a way to know whether or not a tcp port was already in use, so I created test-port in Go.

igo

It may be useful to you to have igo to play with - either to test as a quick way to test very basic go usage or just as a handy commandline calculator.

go get github.com/sbinet/igo

go build -o "$GOPATH/bin/igo" github.com/sbinet/igo

Then you can play around with primitives and math and such

igo

0.1 + 0.2
> 0.300000

buf = make([]byte, 10, 20)
len(buf)
> 10
cap(buf)
> 20

buf[0] = 1
append(buf, 0xff)
len(buf)
> 11

buf
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255}

Unfortunately you can't use import, so it's not super useful, but it is kinda fun for tinkering.

Remember: ctrl+d to exit. :-)


By AJ ONeal

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Published

2015-7-9



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