Add Upgrading From An Older Version On Mac as a go til

README.md

@@ -10,7 +10,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 For a steady stream of TILs from a variety of rocketeers, checkout
 [til.hashrocket.com](https://til.hashrocket.com/).
 
-_583 TILs and counting..._
+_584 TILs and counting..._
 
 ---
 
@@ -197,6 +197,7 @@ _583 TILs and counting..._
 - [Not So Random](go/not-so-random.md)
 - [Replace The Current Process With An External Command](go/replace-the-current-process-with-an-external-command.md)
 - [Sleep For A Duration](go/sleep-for-a-duration.md)
+- [Upgrading From An Older Version On Mac](go/upgrading-from-an-older-version-on-mac.md)
 
 ### Internet
 

go/upgrading-from-an-older-version-on-mac.md

@@ -0,0 +1,27 @@
+# Upgrading From An Older Version On Mac
+
+To upgrade from an older version on Mac, there are a couple manual steps
+that you need to take. For starters, download the latest installer for Mac
+from [Go Lang Download](https://golang.org/dl/).
+
+While this is downloading, you'll need to delete the older version of Go
+that is installed on your machine.
+
+First, remove the existing Go installation directory:
+
+```bash
+$ sudo rm -rf /usr/local/go
+```
+
+Second, clean up the Go `bin` directory from your `PATH` environment
+variable:
+
+```bash
+$ sudo rm /etc/paths.d/go
+```
+
+Now, you can double click on the downloaded installer dmg and follow the
+prompt instructions.
+
+When its all said and done, check `go version` from the command line to see
+that you are now working with the latest.