title: Error "cannot download, $GOPATH not set."
body: <p><strong>Setup:</strong></p>
  
  <p>Have a look at my configuration:</p>
  
  <pre><code>$ echo $GOPATH &amp;&amp; ls -r $GOPATH
  /home/cyrus/.go
  src  pkg  bin
  
  $ echo $GOROOT &amp;&amp; ls $GOROOT
  /usr/local/go
  api  AUTHORS  bin  CONTRIBUTORS  doc  favicon.ico  include  lib  LICENSE  misc  PATENTS  pkg  README  robots.txt  src  test  VERSION
  </code></pre>
  
  <p>You can see that I've set a path for <code>$GOPATH</code>. In addition, I've created subdirectories that I may not need.</p>
  
  <p><strong>Question:</strong></p>
  
  <p>Why does the following command generate this error message?</p>
  
  <pre><code>$ go get code.google.com/p/go-tour/gotour                                                                                                               
  package code.google.com/p/go-tour/gotour: cannot download, $GOPATH not set. For more details see: go help gopath
  </code></pre>