diff --git a/examples/temporary-files-and-directories/temporary-files-and-directories.hash b/examples/temporary-files-and-directories/temporary-files-and-directories.hash
index ebe1eeb..cf6faa7 100644
--- a/examples/temporary-files-and-directories/temporary-files-and-directories.hash
+++ b/examples/temporary-files-and-directories/temporary-files-and-directories.hash
@@ -1,2 +1,2 @@
-371689e72c46daa43eefbd9b9f4eaa3c490e7fd2
-yKWE4QTsYQr
+cc4755e23cb4ba3c0e0ef5554ec9e9477372422a
+nMpjCsALS6P
diff --git a/examples/writing-files/writing-files.hash b/examples/writing-files/writing-files.hash
index 3d09d10..1513200 100644
--- a/examples/writing-files/writing-files.hash
+++ b/examples/writing-files/writing-files.hash
@@ -1,2 +1,2 @@
-d4f19bc0168674b17551bbf55bab7af989452d0e
-8kx-qYUXBpA
+314a0074840e22b328b6412130c17b9bea53c9c9
+fQ7sd4gXv0F
diff --git a/public/temporary-files-and-directories b/public/temporary-files-and-directories
index 3919f36..c6f46d3 100644
--- a/public/temporary-files-and-directories
+++ b/public/temporary-files-and-directories
@@ -45,7 +45,7 @@ time.</p>
             
           </td>
           <td class="code leading">
-            <a href="http://play.golang.org/p/yKWE4QTsYQr"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
+            <a href="http://play.golang.org/p/nMpjCsALS6P"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
           <div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
 </pre></div>
 
@@ -175,6 +175,7 @@ rather than an open file.</p>
           <td class="code leading">
             
           <div class="highlight"><pre>    <span class="nx">dname</span><span class="p">,</span> <span class="nx">err</span> <span class="o">:=</span> <span class="nx">ioutil</span><span class="p">.</span><span class="nx">TempDir</span><span class="p">(</span><span class="s">&quot;&quot;</span><span class="p">,</span> <span class="s">&quot;sampledir&quot;</span><span class="p">)</span>
+    <span class="nx">check</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
     <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="s">&quot;Temp dir name:&quot;</span><span class="p">,</span> <span class="nx">dname</span><span class="p">)</span>
 </pre></div>
 
@@ -241,7 +242,7 @@ prefixing them with our temporary directory.</p>
     </div>
     <script>
       var codeLines = [];
-      codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A    \"fmt\"\u000A    \"io/ioutil\"\u000A    \"os\"\u000A    \"path/filepath\"\u000A)\u000A');codeLines.push('func check(e error) {\u000A    if e != nil {\u000A        panic(e)\u000A    }\u000A}\u000A');codeLines.push('func main() {\u000A');codeLines.push('    f, err := ioutil.TempFile(\"\", \"sample\")\u000A    check(err)\u000A');codeLines.push('    fmt.Println(\"Temp file name:\", f.Name())\u000A');codeLines.push('    defer os.Remove(f.Name())\u000A');codeLines.push('    _, err = f.Write([]byte{1, 2, 3, 4})\u000A    check(err)\u000A');codeLines.push('    dname, err := ioutil.TempDir(\"\", \"sampledir\")\u000A    fmt.Println(\"Temp dir name:\", dname)\u000A');codeLines.push('    defer os.RemoveAll(dname)\u000A');codeLines.push('    fname := filepath.Join(dname, \"file1\")\u000A    err = ioutil.WriteFile(fname, []byte{1, 2}, 0666)\u000A    check(err)\u000A}\u000A');codeLines.push('');
+      codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A    \"fmt\"\u000A    \"io/ioutil\"\u000A    \"os\"\u000A    \"path/filepath\"\u000A)\u000A');codeLines.push('func check(e error) {\u000A    if e != nil {\u000A        panic(e)\u000A    }\u000A}\u000A');codeLines.push('func main() {\u000A');codeLines.push('    f, err := ioutil.TempFile(\"\", \"sample\")\u000A    check(err)\u000A');codeLines.push('    fmt.Println(\"Temp file name:\", f.Name())\u000A');codeLines.push('    defer os.Remove(f.Name())\u000A');codeLines.push('    _, err = f.Write([]byte{1, 2, 3, 4})\u000A    check(err)\u000A');codeLines.push('    dname, err := ioutil.TempDir(\"\", \"sampledir\")\u000A    check(err)\u000A    fmt.Println(\"Temp dir name:\", dname)\u000A');codeLines.push('    defer os.RemoveAll(dname)\u000A');codeLines.push('    fname := filepath.Join(dname, \"file1\")\u000A    err = ioutil.WriteFile(fname, []byte{1, 2}, 0666)\u000A    check(err)\u000A}\u000A');codeLines.push('');
     </script>
     <script src="site.js" async></script>
   </body>
diff --git a/public/writing-files b/public/writing-files
index 49214e1..3b20793 100644
--- a/public/writing-files
+++ b/public/writing-files
@@ -42,7 +42,7 @@ ones we saw earlier for reading.</p>
             
           </td>
           <td class="code leading">
-            <a href="http://play.golang.org/p/8kx-qYUXBpA"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
+            <a href="http://play.golang.org/p/fQ7sd4gXv0F"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
           <div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
 </pre></div>
 
@@ -162,6 +162,7 @@ after opening a file.</p>
           <td class="code leading">
             
           <div class="highlight"><pre>    <span class="nx">n3</span><span class="p">,</span> <span class="nx">err</span> <span class="o">:=</span> <span class="nx">f</span><span class="p">.</span><span class="nx">WriteString</span><span class="p">(</span><span class="s">&quot;writes\n&quot;</span><span class="p">)</span>
+    <span class="nx">check</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
     <span class="nx">fmt</span><span class="p">.</span><span class="nx">Printf</span><span class="p">(</span><span class="s">&quot;wrote %d bytes\n&quot;</span><span class="p">,</span> <span class="nx">n3</span><span class="p">)</span>
 </pre></div>
 
@@ -191,6 +192,7 @@ to the buffered readers we saw earlier.</p>
             
           <div class="highlight"><pre>    <span class="nx">w</span> <span class="o">:=</span> <span class="nx">bufio</span><span class="p">.</span><span class="nx">NewWriter</span><span class="p">(</span><span class="nx">f</span><span class="p">)</span>
     <span class="nx">n4</span><span class="p">,</span> <span class="nx">err</span> <span class="o">:=</span> <span class="nx">w</span><span class="p">.</span><span class="nx">WriteString</span><span class="p">(</span><span class="s">&quot;buffered\n&quot;</span><span class="p">)</span>
+    <span class="nx">check</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
     <span class="nx">fmt</span><span class="p">.</span><span class="nx">Printf</span><span class="p">(</span><span class="s">&quot;wrote %d bytes\n&quot;</span><span class="p">,</span> <span class="nx">n4</span><span class="p">)</span>
 </pre></div>
 
@@ -287,7 +289,7 @@ we&rsquo;ve just seen to the <code>stdin</code> and <code>stdout</code> streams.
     </div>
     <script>
       var codeLines = [];
-      codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A    \"bufio\"\u000A    \"fmt\"\u000A    \"io/ioutil\"\u000A    \"os\"\u000A)\u000A');codeLines.push('func check(e error) {\u000A    if e != nil {\u000A        panic(e)\u000A    }\u000A}\u000A');codeLines.push('func main() {\u000A');codeLines.push('    d1 := []byte(\"hello\\ngo\\n\")\u000A    err := ioutil.WriteFile(\"/tmp/dat1\", d1, 0644)\u000A    check(err)\u000A');codeLines.push('    f, err := os.Create(\"/tmp/dat2\")\u000A    check(err)\u000A');codeLines.push('    defer f.Close()\u000A');codeLines.push('    d2 := []byte{115, 111, 109, 101, 10}\u000A    n2, err := f.Write(d2)\u000A    check(err)\u000A    fmt.Printf(\"wrote %d bytes\\n\", n2)\u000A');codeLines.push('    n3, err := f.WriteString(\"writes\\n\")\u000A    fmt.Printf(\"wrote %d bytes\\n\", n3)\u000A');codeLines.push('    f.Sync()\u000A');codeLines.push('    w := bufio.NewWriter(f)\u000A    n4, err := w.WriteString(\"buffered\\n\")\u000A    fmt.Printf(\"wrote %d bytes\\n\", n4)\u000A');codeLines.push('    w.Flush()\u000A');codeLines.push('}\u000A');codeLines.push('');codeLines.push('');codeLines.push('');
+      codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A    \"bufio\"\u000A    \"fmt\"\u000A    \"io/ioutil\"\u000A    \"os\"\u000A)\u000A');codeLines.push('func check(e error) {\u000A    if e != nil {\u000A        panic(e)\u000A    }\u000A}\u000A');codeLines.push('func main() {\u000A');codeLines.push('    d1 := []byte(\"hello\\ngo\\n\")\u000A    err := ioutil.WriteFile(\"/tmp/dat1\", d1, 0644)\u000A    check(err)\u000A');codeLines.push('    f, err := os.Create(\"/tmp/dat2\")\u000A    check(err)\u000A');codeLines.push('    defer f.Close()\u000A');codeLines.push('    d2 := []byte{115, 111, 109, 101, 10}\u000A    n2, err := f.Write(d2)\u000A    check(err)\u000A    fmt.Printf(\"wrote %d bytes\\n\", n2)\u000A');codeLines.push('    n3, err := f.WriteString(\"writes\\n\")\u000A    check(err)\u000A    fmt.Printf(\"wrote %d bytes\\n\", n3)\u000A');codeLines.push('    f.Sync()\u000A');codeLines.push('    w := bufio.NewWriter(f)\u000A    n4, err := w.WriteString(\"buffered\\n\")\u000A    check(err)\u000A    fmt.Printf(\"wrote %d bytes\\n\", n4)\u000A');codeLines.push('    w.Flush()\u000A');codeLines.push('}\u000A');codeLines.push('');codeLines.push('');codeLines.push('');
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