title: Compare integer in bash, unary operator expected
body: <p>The following code gives </p>
  
  <blockquote>
    <p>[: -ge: unary operator expected</p>
  </blockquote>
  
  <p>when </p>
  
  <pre><code>i=0
  
  if [ $i -ge 2 ]
  then
      #some code
  fi
  </code></pre>
  
  <p>why?</p>