title: what does this bash if statement mean?
body: <p>What does the following bash script mean: </p>
  
  <p><code>if [ -d "directory name" -a ! -L "directory name" ]; then
    # do something
  fi
  </code>
  I can understand up to here: </p>
  
  <blockquote>
    <p>if [ -d "directory name"</p>
  </blockquote>
  
  <p>but I'm lost after that.  Extra consideration if, in addition to explanation, docs that explain -a ! -L</p>