How can I just get content inside a shortcode or just outside

Depends on the shortcode. If you have access to the shortcode’s handler function, that function’s second argument is the content inside the shortcode:

function wpse20136_shortcode( $atts, $content ){
  // $content has the content inside xxx
}

register_shortcode( 'xxx', 'wpse20136_shortcode' );

For getting all content not in shortcodes, that’s easy. strip_shortcodes() does that:

strip_shortcodes( get_the_content() );

for example, will give you the content of the current post with only the content not inside shortcodes.