title: Consolidate multiple if statements in Ksh
body: <p>How can I consolidate the following if statements into a single line?</p>
  
  <pre><code>if [ $# -eq 4 ]
  then
          if [ "$4" = "PREV" ]
          then
                  print "yes"
          fi
  fi
  if [ $# -eq 3 ]
  then
          if [ "$3" = "PREV" ]
          then
                  print "yes"
          fi
  fi
  </code></pre>
  
  <p>I am using ksh. </p>
  
  <p>Why does this give an error?</p>
  
  <pre><code>if [ [ $# -eq 4 ] &amp;&amp; [ "$4" = "PREV" ] ]
          then
                  print "yes"
          fi
  </code></pre>
  
  <p>Error:</p>
  
  <blockquote>
    <p>0403-012 A test command parameter is not valid.</p>
  </blockquote>