title: Get parent directory of shell script's directory
body: <p>I have a shell script here:</p>
  
  <pre><code>/node_modules/.bin/exec.sh
  </code></pre>
  
  <p>in the exec.sh script, I want to obtain the path of the directory's parent directory that the script is contained in (not pwd/cwd!). I can obtain the containing directory like so:</p>
  
  <pre><code>`dirname $0`
  </code></pre>
  
  <p>which will yield:</p>
  
  <pre><code>/node_modules/.bin
  </code></pre>
  
  <p>but I am looking to get at one directory higher, I just want to get</p>
  
  <pre><code>/node_modules
  </code></pre>
  
  <p>I am having trouble searching for the answer, my guess is:</p>
  
  <pre><code>`dirname $1`
  </code></pre>
  
  <p>but just a guess, not sure if that's right at all. Can anyone give an explanation of how to do this and how it works?</p>