title: binary operator expected error when checking if a file with full pathname exists
body: <pre><code>pathname=$(cat $HOME/.rm.cfg)
  if [ ! -z $pathname/$1 ]
  </code></pre>
  
  <p><code>.rm.cfg</code> is a file that contains the following directory</p>
  
  <blockquote>
    <p>/home/username/deleted1 </p>
  </blockquote>
  
  <p><code>$1</code> is the name of a file eg. glass </p>
  
  <p>why does the line if <code>[ ! -z $pathname/$1 ]</code> give a binary operator expected error. </p>