How to install the Go Tour on your Mac

After reading an interesting article describing how the SoundCloud dev team uses Go, I decided to learn more about this new language. I started by visiting the Tour, and followed the advice to run it locally. Unfortunately, the instructions on the page are missing a few key steps. Here's how I got the Go Tour installed on my Lion machine:

1) Download the Go package installer for Mac OS X and install Go

2) Restart Terminal

3) Install Mercurial with Homebrew (if you don't have Homebrew installed, follow my guide for setting up a development environment on a Mac):

$ brew update   # make sure Homebrew is up to date
$ brew doctor   # make sure your system is raring to brew
$ brew install mercurial    # or brew install hg

4) In Terminal, run the following command:

$ sudo go get code.google.com/p/go-tour/gotour

Without sudo, you will probably get this permission denied error:

package code.google.com/p/go-tour/gotour: mkdir /usr/local/go/src/pkg/code.google.com: permission denied

5) Launch the Tour:

$ gotour

If everything went well, you should see the something like this:

2012/07/25 18:12:15 Serving content from /usr/local/go/src/pkg/code.google.com/p/go-tour
2012/07/25 18:12:15 Open your web browser and visit http://127.0.0.1:3999/

6) Open the Tour in your browser by going to http://127.0.0.1:3999/ and learn about neat Go features, such as quick initialization of variables, even if they're not of the same type:

var x, y, z int = 1, 2, 3
var c, python, java = true, false, "no!"

Mountain Lion Update: If you successfully installed Go on Lion, and then upgraded to Mountain Lion, you will have to repeat steps 1 and 2 before being able to run gotour.