title: error "0: command not found" on a comment line
body: <p>Help! I get an error A1.sh: line 205: 0: command not found after running my script.</p>
  
  <p>What baffles me is that the line 205 is a comment! I have tried editing it but still get an error on the same line. All my line endings are LF. </p>
  
  <p>Below is the block of code after editing, line 205 is now:</p>
  
  <pre><code>if `doesBookExist "$title" "$author"`
  </code></pre>
  
  <p>Full block of code:</p>
  
  <pre><code>if [[ bookExist -gt 0 ]]
  then
      # get title from actual book (in case title input has bad case)
      actualTitle=`cut -d ':' -f 1 BookDB.txt | grep -i "^$title$"`
      sed -i "/^$title:$author.*$/Id" $FILENAME
      if `doesBookExist "$title" "$author"`
      then
          title=`echo "$title" | tr "@" ":"`
          echo
          echo "Book title '$actualTitle' could not be removed!"
      else
          title=`echo "$title" | tr "@" ":"`
          echo
          echo "Book title '$actualTitle' removed successfully!"
      fi
  else
      echo
      echo 'Book does not exist!'
  fi
  </code></pre>
  
  <p>Any help is appreciated!</p>