title: How to count occurrences of all the words in all the files of a directory? But with count incremented only once per word per file
body: <p>I have already asked a similar question but people misunderstood what i was asking. I was asking how to generate a list of every word with a word count incremented only once per word per file.</p>
  
  <p>fore example, I have a directory with 10 files , i want to generate a list of words using bash commands which says a value of 1-10 depending on how many files they appear in.</p>
  
  <p>eg.</p>
  
  <pre><code>10 The
  10 and
  8 bash
  7command
  6 help....
  ect.
  </code></pre>
  
  <p>I already know that <code>grep -l word *|wc -l</code> will search for a single word but i want to create a list of all words.</p>
  
  <p>Is there a way to combine that with  <code>tr '[A-Z]' '[a-z]' | tr -d '[:punct:]'</code> so that words with capital letters aren;t duplicated and puntuation is removed?</p>