title: Shell: too many argument by '!'
body: <pre><code>n='!' &amp;&amp; [ -n ${n} ] &amp;&amp; echo "n=$n"
  </code></pre>
  
  <p>produces the following message </p>
  
  <pre><code>[: too many arguments
  </code></pre>
  
  <p>Why?</p>
  
  <p>EDIT: </p>
  
  <p>I'm using <code>zsh</code></p>
  
  <pre><code>➔ echo $ZSH_VERSION
  5.0.7
  </code></pre>
  
  <p>(with <code>oh-my-zsh</code>)</p>