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:   </tbody>
  </table>
  
  Bash’s built-in `set` command can be used to enable and disable options. To enable an option use the `-` argument, and to disable an option use the `+` argument.
  
  For example, the following script enables the most commonly used options for build scripts:
  
  ```bash
  #!/bin/bash
  
negative.code: 
  ```bash
  #!/bin/bash
  
  # Note that we don't enable the 'e' option, which would cause the script to 
  # immediately exit if 'run_tests' failed
  set -uo pipefail
  
  run_tests
  
  