title: Passing arguments in unix in command line
body: <p>How can I pass arguments to a command in unix? For example, if I have to open a file:</p>
  
  <pre><code>R&gt; vi john/pic/mars/NASA/rover.txt
  </code></pre>
  
  <p>In the above <code>vi</code> command, I want to replace "mars" with a variable, and pass the variable value in the same line, as in:</p>
  
  <pre><code>R&gt; vi john/pic/$variable/NASA/rover.txt | $varaiable=pluto
  </code></pre>
  
  <p>Of course this doesn't work. But I hope my question is clear. Can anyone help me with this?</p>