title: difference between tar zxf vs -xvf
body: <p>I have a downloaded version of <a href="http://agentzh.org/misc/nginx/openresty-1.9.7.3.tar" rel="nofollow">http://agentzh.org/misc/nginx/openresty-1.9.7.3.tar</a> . I rename it to openresty-1.9.7.3.tar.gz.  </p>
  
  <p>I am trying to do the following in centOS-6.x:</p>
  
  <pre><code>tar zxf openresty-1.9.7.3.tar.gz
  gzip: stdin: not in gzip format
  tar: Child returned status 1
  tar: Error is not recoverable: exiting now
  </code></pre>
  
  <p>whereas :</p>
  
  <p><code>tar -xvf openresty-1.9.7.3.tar.gz</code> works and untars to openresty-1.9.7.3.tar.gz. </p>
  
  <p>Any reasons why the first one won't work? It works in my personal laptop but won't wont work in a server.</p>