title: Error about running Go Tour locally: Couldn't find tour files: could not find go-tour content; check $GOROOT and $GOPATH
body: <p><code>go version go1.12.9 darwin/amd64</code></p>
  <p>After I installed the <code>golang.org/x/tour</code> package, I ran the command <code>tour</code> and got an error:</p>
  <pre><code>Couldn't find tour files: could not find go-tour content; check $GOROOT and $GOPATH
  </code></pre>
  <p>Here is the output of <code>go env</code>:</p>
  <pre><code>GOARCH=&quot;amd64&quot;
  GOBIN=&quot;&quot;
  GOCACHE=&quot;/Users/elk/Library/Caches/go-build&quot;
  GOEXE=&quot;&quot;
  GOFLAGS=&quot;&quot;
  GOHOSTARCH=&quot;amd64&quot;
  GOHOSTOS=&quot;darwin&quot;
  GOOS=&quot;darwin&quot;
  GOPATH=&quot;/Users/elk/ccode/go&quot;
  GOPROXY=&quot;https://goproxy.io&quot;
  GORACE=&quot;&quot;
  GOROOT=&quot;/usr/local/go&quot;
  GOTMPDIR=&quot;&quot;
  GOTOOLDIR=&quot;/usr/local/go/pkg/tool/darwin_amd64&quot;
  GCCGO=&quot;gccgo&quot;
  CC=&quot;clang&quot;
  CXX=&quot;clang++&quot;
  CGO_ENABLED=&quot;1&quot;
  GOMOD=&quot;/dev/null&quot;
  CGO_CFLAGS=&quot;-g -O2&quot;
  CGO_CPPFLAGS=&quot;&quot;
  CGO_CXXFLAGS=&quot;-g -O2&quot;
  CGO_FFLAGS=&quot;-g -O2&quot;
  CGO_LDFLAGS=&quot;-g -O2&quot;
  PKG_CONFIG=&quot;pkg-config&quot;
  GOGCCFLAGS=&quot;-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/5d/q9dj2fxx4t71w0g5g00cvlkh0000gn/T/go-build144784202=/tmp/go-build -gno-record-gcc-switches -fno-common&quot;
  </code></pre>
  <p>I add two lines in <code>.zshrc</code>：</p>
  <pre><code>export GOPATH=&quot;$HOME/ccode/go&quot;
  export PATH=&quot;$PATH:$GOPATH/bin&quot;
  </code></pre>
  <p>The command <code>go get golang.org/x/tour</code> was running with no error.</p>
  <p>The strange thing is:
  <code>echo $GOROOT</code> will display a blank line
  And <code>echo $GOPATH</code> is consistent with <code>go env</code>.</p>