Check out example codes for "css sass scss". It will help you in understanding the concepts better.

Code Example 1

/*SMART DIFFERENCE*/
/*CSS*/
body {
  font: 100% Helvetica, sans-serif;
  color: #333;
}

/*SCSS*/

$font-stack:    Helvetica, sans-serif;
$primary-color: #333;

body {
  font: 100% $font-stack;
  color: $primary-color;
}


/*SASS*/
$font-stack:    Helvetica, sans-serif
$primary-color: #333

body
  font: 100% $font-stack
  color: $primary-color

Code Example 2

sass --watch input.scss output.css

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