anchor.diff:  
   <section class="Docs__troubleshooting-note">
     <h1>Unbound variable errors</h1>
  -  <p>Note that while the <code>u</code> option is generally a good default to use for all build scripts, it can cause some tools like <a href="https://rvm.io">rvm</a> to fail with “unbound variable” errors. If you encounter errors, remove the <code>u</code> from the set command in your script.</p>
  +  <p>Note that while enabling the <code>u</code> option is generally a good default to use for all build scripts, it can cause some tools like <a href="https://rvm.io">rvm</a> to fail with “unbound variable” errors. If you encounter errors, you can either remove <code>u</code> from the list of options, or you can surround the command causing the error with <code>set +u</code> and <code>set -u</code> to temporarily disable the option.</p>
   </section>
   
   ## Capturing exit status
  
positive.code: 
  ```bash
  #!/bin/bash
  
  run_tests
  
  
negative.code:   </tbody>
  </table>
  
  Bash’s built-in `set` command can be used to enable and disable options. For example, `set -u` enables the `u` option, and `set +u` disables the `u` option. You can also set multiple options at once, for example `set -ue` enables both the `u` and `e` options.
  
  The following example enables the most commonly used options for build scripts:
  
  ```bash
  #!/bin/bash
  