title: How to concatenate variable with slash as a new string
body: <p>I have the following bash code:</p>
  
  <pre><code>FULLSTR="/FOO/BAR/QUX"
  IFS=/
  ARY=($FULLSTR)
  </code></pre>
  
  <p>What I want to do is to concatenate the 2nd and 3rd element of <code>ARY</code> with 
  <code>/</code> and assigned it into a variable. The end result I hope to get is <code>/BAR/QUX</code>.</p>
  
  <p>But why this doesn't work:</p>
  
  <pre><code>NSTR=/${ARY[2]}/${ARY[3]}
  echo $NSTR
  </code></pre>
  
  <p>It produces:</p>
  
  <pre><code> BAR QUX
  </code></pre>
  
  <p>What's the right way to do it?</p>