title: What does "set - $VARIABLE" mean in bash?
body: <p>Recenly, i read <a href="http://shop.oreilly.com/product/9780596009656.do" rel="nofollow noreferrer">Learning the bash Shell, 3rd Edition</a> in chapter 7 section "Reading user input". When i
  See the code below,</p>
  
  <pre><code>echo 'Select a directory:'
  done=false
  
  while [ $done = false ]; do
          do=true
          num=1
          for direc in $DIR_STACK; do
                  echo $num) $direc
                  num=$((num+1))
          done
          echo -n 'directory? '
          read REPLY
  
          if [ $REPLY -lt $num ] &amp;&amp; [ $REPLY -gt 0 ]; then
                  set - $DIR_STACK
  
                  #statements that manipulate the stack...
  
                  break
          else
                  echo 'invalid selection.'
          fi
  done
  </code></pre>
  
  <p>What is the exact meaning of <code>set - $DIR_STACK</code>?</p>