title: what is difference between "tar -xvf" and "tar xvf" on Linux?
body: <p>I am extracting a tar file on linux server using below commands</p>
  
  <pre><code>tar xvf httpd-2.2.31.tar
  tar -xvf httpd-2.2.31.tar
  </code></pre>
  
  <p>both are having same output, what does hyphen(<code>-</code>) mean here?</p>