title: Count number of blank lines in a file
body: <p>In <a href="https://stackoverflow.com/questions/114814/count-non-blank-lines-of-code-in-bash">count (non-blank) lines-of-code in bash</a> they explain how to count the number of non-empty lines. </p>
  
  <p>But is there a way to count the number of blank lines in a file? By blank line I also mean lines that have spaces in them. </p>