title: How to gunzip without overwriting non-interactively
body: <p>I want to unzip <code>.gz</code> files but without overwriting. When the resulting file exists, gunzip will ask for permission to overwrite, but I want gunzip not to overwrite by default and just abort. I read in a man that <code>-f</code> force overwriting, but I haven't found nothing about skipping it.</p>
  
  <pre><code>gunzip ${file} 
  </code></pre>
  
  <p>I need something like <code>-n</code> in copying <code>cp -n ${file}</code></p>