title: Error in if statement in shell script
body: <p>I am trying to execute the following shell script</p>
  
  <pre><code>#!/bin/csh
  if [[ $# != 1  ||  $1 != "first" &amp;&amp; $1 != "second" ]]
  then
      echo "Error: Usage: $0 [first|second]"
      exit 1
  fi
  </code></pre>
  
  <p>but I am getting an error:</p>
  
  <p>if: Expression Syntax.</p>
  
  <p>I have no idea what's wrong with that syntax. It looks fine to me. please help.</p>