title: Get remaining letters in shell/terminal from alphabet which aren't used
body: <p>I try to make a hangman game in terminal
  I want do display the char's which aren't used yet, example:
  User has given the char's: A, B, C &amp; D. 
  I want to show: "chars left: EFGHIJKLM....."</p>
  
  <p>My Code:</p>
  
  <pre><code>for x in {a..z}
  do
      if [ "$x" != "$GUESSED" ]; then 
          LETTERSLEFT="$LETTERSLEFT $x"    
      fi
  done
  }
  </code></pre>
  
  <p>What I try to do:
  If $x not in the guessed answer, add this to $lettersleft</p>